US 5,928,648 AGrant
Recombinant Herpesvirus of Turkeys and Uses Thereof
Issue Date:1999-07-27
•7 Claims
•20 Drawing Sheets
Abstract
The present invention relates to a recombinant herpesvirus of turkeys comprises foreign DNA inserted into a site in the herpesvirus of turkeys genome which is not essential for replication of the herpesvirus of turkeys. The invention further relates to homology vectors which produce recombinant herpesvirus of turkeys by inserting foreign DNA into herpesvirus of turkeys genome. Genetically-engineered virus S-FPV-062 is described in the Materials and Methods section which follows. One advantage of recombinant HVT as live vaccines is that they may be engineered to express only a limited number of antigens that are needed to confer protective immunity to the corresponding pathogens. Consequently, host animals vaccinated with the recombinant HVT can be distinguished from those which have been infected with the wild type virus by the absence of antigens that are normally present in the wild type virus.
Metadata
Assignee
- Syntro Corporation
Inventor
- Mark D. Cochran
Application Information
Application Number:US 0236101
Filing Date:1993-02-26
Priority Date:1985-09-06
Art Unit:185
Classifications
IPC:
A61K 39255A61K 39295C12N 701
Field of Search:
424435184.1;199.1;229.1;204.169.3;172.3;235.1;236;320.1;252.3
Patent Drawings (20 sheets)
Description
BACKGROUND OF THE INVENTION
The ability to isolate DNA and clone this isolated DNA into bacterial plasmids has greatly expanded the approaches available to make viral vaccines. The methods used to make the present invention involve modifying cloned DNA sequences from various pathogens of animals, by insertions, deletions, single or multiple base changes, and subsequent insertions of these modified sequences into the genome of the virus. One utility of the addition of foreign sequences is achieved when the foreign sequence encodes a foreign protein that is expressed during viral infection of the animal. The resulting live virus may then be used in a vaccine to elicit an immune response in a host animal and provide protection to the animal against disease. A virus with these characteristics is referred to as a viral vector, because it becomes a living vector that will carry and express the foreign protein in the host animal. In effect it becomes an elaborate delivery system for the foreign protein(s).
More specifically, the present invention relates to the use of herpesvirus of turkeys (HVT) as a viral vector for vaccination of birds against disease. The group of herpesviruses comprise various pathogenic agents that infect and cause disease in a number of target species: swine, cattle, chickens, horses, dogs, cats, etc. Each herpesvirus is specific for its host species, but they are all related in the structure of their genomes, their mode of replication, and to some extent in the pathology they cause in the host animal and in the mechanism of the host immune response to the virus infection.
The application of recombinant DNA techniques to animal viruses has a relatively recent history from about 1990. The first viruses to be engineered have been those with the smallest genomes. In the case of the papovaviruses, because these viruses are so small and cannot accommodate much extra DNA, their entire use in genetic engineering has been as defective replicons. Foreign gene expression from these viruses requires a wild-type helper virus and is limited to cell culture systems. For adenoviruses, there is a small amount of nonessential DNA that can be replaced by foreign sequences. The only foreign DNA that seems to have been expressed in adenoviruses are the T-antigen genes from papovaviruses (Mansour, et al., Proc. Natl. Acad. Sci. US, 1985; Thummel, et al., Cell, 1983; Scolnick, et al., Cell, 1981; Thummel, et al., Cell, 1981), and the herpes simplex virus (HSV) thymidine kinase gene (Haj-Ahmed and Graham, J. of Virology, 1986). These publications do not identify the nonessential regions in HVT wherein foreign DNA may be inserted, nor do they teach how to achieve the expression of the foreign genes in HVT, e.g., which promoter sequence and termination sequence to use.
Another group of viruses that have been engineered are the poxviruses. One member of this group, vaccinia, has been the subject of much research on foreign gene expression. Poxviruses are large DNA-containing viruses that replicate in the cytoplasm of the infected cell. They have a structure that is unique in that they do not contain any capsid that is based upon icosahedral symmetry or helical symmetry. The poxviruses are most likely to have evolved from bacterial-like microorganisms through the loss of function and degeneration. In part due to this uniqueness, the advances made in the genetic engineering of poxviruses cannot be directly extrapolated to other viral systems, including herpesviruses and HVT. Vaccinia recombinant virus constructs have been made in a number of laboratories that express the following inserted foreign genes: HSV thymidine kinase gene (Mackett, et al., Proc. Natl. Acad. Sci. USA, 1982; Panicali and Paoletti, Proc. Natl. Acad. Sci. USA, 1982, hepatitis B surface antigen (Paoletti, et al., Proc. Natl. Acad. Sci. USA, 1984; Smith et al., Nature, 1983), HSV glycoprotein D gene, influenzae hemagglutinin gene (Panicali, et al., Proc. Natl. Acad. Sci. USA, 1983; Smith, et al., Proc. Natl. Acad. Sci. USA, 1983), malaria antigen gene (Smith, et al., Science, 1984, and vesicular stomatitis glycoprotein G gent (Mackett, et al., Science, 1986). The general overall features of vaccinia recombinant DNA work are similar to the techniques used for all the viruses, especially as they relate to the techniques in reference (Maniatis, et al., Molecular Cloning, 1982). However in detail, the vaccinia techniques are not applicable to herpesviruses and HVT. The utility of vaccinia as a vaccine vector is in question because of its close relationship to human smallpox and its known pathogenicity to humans. Thus, the use of the host-specific herpesvirus HVT is a better solution to vaccination of poultry.
Among the primate herpesviruses, only HSV of humans and, to a limited extent, herpes saimiri of monkeys have been engineered to contain foreign DNA sequences. The first use of recombinant DNA to manipulate HSV involved cloning a piece of DNA from the L-S junction region into the unique long region of HSV DNA, specifically into the thymidine kinase gene (Moccarski, et al., Cell, 1980). This insert was not a foreign piece of DNA, rather it was a naturally occurring piece of herpesvirus DNA that was duplicated at another place in the genome. This piece of DNA was not engineered to specifically express a protein, and thus the work does not involve expression of protein in herpesviruses. The next manipulation of HSV involved the creation of deletions in the virus genome by a combination of recombinant DNA techniques and thymidine kinase selection. Using this approach, the HSV alpha-22 gene has been deleted (Post, et al., Cell, 1981), and a 15,000 basepair sequence of DNA has been deleted from the internal repeat of HSV (Poffenberger, et al., Proc. Natl. Acad. Sci. USA, 1981).
The insertion of genes that encode protein into herpesviruses have involved seven cases: the insertion of HSV glycoprotein C back into a naturally occurring deletion mutant of this gene in HSV (Gibson and Spear, J. of Virology, 1983); the insertion of glycoprotein D of HSV type 2 into HSV type 1 (Lee, et al., Proc. Natl. Acad. Sci. USA, 1982), again with no manipulation of promoter sequences since the gene is not `foreign`; the insertion of hepatitis B surface antigen into HSV under the control of the HSV ICP4 promoter (Shih, et al., Proc. Natl. Acad. Sci. USA, 1984); and the insertion of bovine growth hormone into herpes saimiri virus with an SV40 promoter (the promoter did not work this system and an endogenous upstream served to transcribe the gene) (Desrosiers, et al., 1984). Two additional cases of foreign genes (chicken ovalbumin gene and Epstein-Barr virus nuclear antigen) have been inserted into HSV (Arsenakis and Roizman, 1984), and glycoprotein X of pseudorabies virus has been inserted into HSV (Post, et al., 1985).
These limited cases of deletion and insertion of genes into herpesviruses demonstrate that it is possible to genetically engineer herpesvirus genomes by recombinant DNA techniques. The methods that have been used to insert genes involve homologous recombination between the viral DNA cloned in plasmids and purified viral DNA transfected into the same animal cell. However, the extent to which one can generalize the location of the deletion and the sites for insertion of foreign genes is not known from these previous studies.
One object of the present invention is a vaccine for Marek's disease. Marek's disease virus (MDV) is the causative agent of Marek's disease which encompasses fowl paralysis, a common lymphoproliferative disease of chickens. The disease occurs most commonly in young chickens between 2 and 5 months of age. The prominent clinical signs are progressive paralysis of one or more of the extremities, incoordination due to paralysis of legs, drooping of the limb due to wing involvement, and a lowered head position due to involvement of the neck muscles. In acute cases, severe depression may result. In the case of highly oncogenic strains, there is characteristic bursal and thymic atrophy. In addition, there are lymphoid tumors affecting the gonads, lungs, liver, spleen, kidney and thymus (Mohanty and Dutta, 1981).
Most chickens are vaccinated against MDV at one day of age to protect the bird against MDV for life. Prior to the present invention, the principal vaccination method for MDV involved using naturally occurring strains of turkey herpesvirus (HVT). It would be advantageous to incorporate other antigens into this vaccination at one day of age, but efforts to combine conventional vaccines have not proven satisfactory to date due to competition and immunosuppression between pathogens. The multivalent HVT-based vaccines engineered in this invention represent a novel way to simultaneously vaccinate against a number of different pathogens. For the first time, a recombinant HVT with a foreign gene inserted into a non-essential region of the HVT genome is disclosed.
The types of genetic engineering that have been performed on these herpesviruses consist of cloning parts of the virus DNA into plasmids in bacteria, reconstructuring the virus DNA while in the cloned state so that the DNA contains deletions of certain sequences, and furthermore adding foreign DNA sequences either in place of the deletions or at sites removed from the deletions.
A foreign gene of interest targeted for insertion into the genome of HVT may be obtained from any pathogenic organism of interest. Typically, the gene of interest will be derived from pathogens that cause diseases in poultry that have an economic impact on the poultry industry. The genes may be derived from organisms for which there are existing vaccines, and because of the novel advantages of the vectoring technology the HVT derived vaccines will be superior. Also, the gene of interest may be derived from pathogens for which there is currently no vaccine but where there is a requirement for control of the disease. Typically, the gene of interest encodes immunogenic polypeptides of the pathogen, and may represent surface proteins, secreted proteins and structural proteins.
A relevant avian pathogen that is a target for HVT vectoring in the present invention is Infectious Laryngotracheitis virus (ILT). ILT is a member of the herpesviridiae family, and this pathogen is causes an acute disease of chickens which is characterized by respiratory depression, gasping and expectoration of bloody exudate. Viral replication is limited to cells of the respiratory tract, where in the trachea the infection gives rise to tissue erosion and hemorrhage. In chickens, no drug has been effective in reducing the degree of lesion formation or in decreasing clinical signs. Vaccination of birds with various modified forms of the ILT virus derived by cell passage and/or tedious regimes of administration have conferred acceptable protection in susceptible chickens. Because of the degree of attenuation of current ILT vaccines care must be taken to assure that the correct level of virus is maintained; enough to provide protection, but not enough to cause disease in the flock.
An additional target for the HVT vectoring approach and a subject of this invention is Newcastle disease, an infectious, highly contagious and debilitating disease that is caused by the Newcastle disease virus (NDV). NDV is a single-stranded RNA virus of the paramyxovirus family. The various pathotypes of NDV (velogenic, mesogenic, lentogenic) differ with regard to the severity of the disease, the specificity and symptoms, but most types seem to infect the respiratory system and the nervous system. NDV primarily infects chickens, turkeys and other avian species. Historically vaccination has been used to prevent disease, but because of maternal antibody interfences, life-span of the bird and route of administration, the producer needs to adapt immunization protocols to fit specific needs.
SUMMARY OF THE INVENTION
The present invention provides a recombinant herpesvirus of turkeys (HVT) which comprises the genomic DNA of herpesvirus of turkey containing foreign DNA not usually present within such genomic DNA. The foreign DNA is inserted within a region of the genomic DNA which is not essential for replication of the herpesvirus of turkeys and DNA corresponding to a promoter is located upstream of the said foreign DNA.
The invention provides for a homology vector for producing a recombinant herpesvirus of turkeys by inserting foreign DNA into the genomic DNA of a herpesvirus of turkeys. The homology vector comprises a double-stranded DNA molecule consisting essentially of a double-stranded foreign DNA not usually present within the herpesvirus of turkeys genomic DNA, with at one end of the foreign DNA, double-stranded herpesvirus of turkeys DNA homologous to genomic DNA located at one side of a site on the genomic DNA which is not essential for replication of the herpesvirus of turkeys, and at the other end of the foreign DNA, double-stranded herpesvirus of turkeys DNA homologous to genomic DNA located at the other side of the same site on the genomic DNA.
BRIEF DESCRIPTION OF FIGURES
FIGS. 1A-1C
Details of HVT Construction and Map Data
A. BamHI restriction fragment map of HVT. Fragments are numbered in order of decreasing size; letters refer to small fragments whose comparative size has not been determined.
B. BamHI #16 fragment showing location of .beta.-galactosidase gene insertion in S-HVT-001.
C. BamHI #19 fragment showing location of .beta.-galactosidase gene insertion.
Legend: B=BamHI; X=XhoI; H=HindIII; P=PstI; S=SalI; N=NdeI; R=EcoRI.
FIG. 2A, FIG. 2B, FIG. 2C and FIG. 2D
Insertion in Plasmid 191-47
FIGS. 3A-3B
Details of S-HVT-003 Construction
A. Restriction map of HVT DNA in the region of the BamHI #16 fragment. This fragment is contained within large HindIII fragment that has no name in the prior art to applicants' knowledge. Shown also is the XhoI site (X) where applicants have made their constructions the XhoI site was first changed to an EcoRI (R) site by use of a "linker" and standard cloning procedures. Also, shows details of the construction of the beta-gal gene and IBVD gene inserted into the BamHI #16 fragment for use in homologous recombination. Both genes were under the control of the PRV gX gene promoter (gX).
B. The S-HVT-003 genome showing the location of the two inserted foreign genes, .beta.-gal and IBDV.
Legend: H=HindIII; B=BamHI; X=XhoI; R=EcoRI; Xb=XbaI; Hp=HpaI; S=SmaI; UL=unique long region; US=unique short region; IR=internal repeat region; TR=terminal repeat region.
FIG. 4
Western blot showing the differential expression of the IBDV 32 kD antigen in cellular lysates of S-HVT-003 infected cells (32 kD present) and S-HVT-001 infected cells (32 kD negative). IBDV specific polypeptides were identified by probing the blot with hyper-immune rat antiserum directed against denatured IBDV virions. This serum reacts primarily with the immunodominant 32 kD antigen (VP3). The lanes on the blot contain: 1) Protein Molecular Weight Standards, 2) uninfected CEF cells, 3) S-HVT-001 infected CEF's, 4) 5) & 6) S-HVT-003 and 7) IBDV virion polypeptides.
FIG. 5
Western blot showing the presence of the 42 kD IBDV polypeptide (VP2) product in cellular lysates derived from CEF cells infected with either wild-type HVT virus or with S-HVT-001 that expresses .beta.-galactosidase. IBDV specific polypeptides were identified using a VP-2 specific rabbit anti-peptide antiserum. The lanes contain: 1) Protein Molecular Weight Standards, 2) wild-type HVT infected CEF's, 3) S-HVT-001 infected CEF's, 4) S-HVT-003 infected CEF's, 5) S-HVT-003 infected CEF's, and 6) IBDV virion polypeptides.
FIGS. 6A-6C
Details of S-HVT-004 Construction
A. Restriction map of HVT DNA in the region of the BamHI #16 fragment. This fragment is contained within a large HindIII fragment that has no name in the prior art to applicants' knowledge. Shown also is the XhoI site (X) where applicants have made their insertion: for these constructions the XhoI site was first changed to an EcoRI (R) site by use of a "linker" and standard cloning procedures.
B. Details of the construction of the .beta.-gal gene and MDV gA gene inserted into the BamHI #16 fragment for use in homologous recombination. Beta-gal was under the control of the PRV gX gene promoter (gX), while the MDV gA gene was under the control of its own promoter.
C. The S-HVT-004 genome showing the location of the two inserted foreign genes, .beta.-gal and MDV gA.
Legend: H=HindIII; B=BamHI; X=XhoI; R=EcoRI; Xb=XbaI; UL=unique long region; US=unique short region; IR=internal repeat region; TR=terminal repeat region.
FIG. 7A and FIG. 7B
FIG. 7 is a detailed description of the .beta.-galactosidase (lacZ) marker gene insertion in homology vector 467-22.A12. The diagram shows the orientation of DNA fragments assembled in the marker gene. The origin of each fragment is described in the Materials and Methods section. The sequences located at the junctions between each fragment and at the ends of the marker gene are shown. The restriction sites used to generate each fragment are indicated at the appropriate junction. The location of the lacZ gene coding region is also given. Numbers in parenthesis ( ) refer to amino acids, and restriction sites in brackets ! indicate the remnants of sites which were destroyed during construction. The following abbreviations are used, pseudorabies virus (PRV), lactose operon Z gene (lacZ), Escherichia coil (E. Coli), poly adenylation signal (pA), and glycoprotein X (gpx).
FIG. 8
FIG. 8 is a BamHI, NotI restriction map of the HVT genome. The unique long UL and unique short US regions are shown. The long and short region repeats are indicated by boxes. The BamHI fragments are numbered in decreasing order of size. The location of probes P1-P4 are indicated. The origin of each probe is as follows: P1--BamHI #6, P2--BamHI #2, P3--BamHI #13, and P4--4.0 kb BgIII to StuI sub-fragment of HVT genomic XbaI fragment #5 (8.0 kb).
FIG. 9
FIG. 9 describes the creation of plasmid pSY229.
FIG. 10A and FIG. 10B
Detailed description of the MDV gene cassette insert in Homology Vectors 456-18.18 and 456-17.22. The diagram shows the orientation of DNA fragments assembled in the cassette. The origin of each fragment is described in the Materials and Methods section. The sequences located at the junctions between each fragment and at the ends of the marker gene are shown, including junction A (SEQ ID NO: 34), junction B (SEQ ID NO: 35), and junction C (SEQ ID NO: 36). The restriction sites used to generate each fragment are indicated at the appropriate junction. The location of the MDV gA and gB genes is also given. Numbers in parenthesis ( ) refer to amino acids, and restriction sites in brackets ! indicate the remnants of sites which were destroyed during construction.
FIG. 11A and FIG. 11B
Detailed description of the HindIII fragment insert in Homology Vector 556-41.5. The diagram shows the orientation of DNA fragments assembled in the cassette. The origin of each fragment is described in the Materials and Methods section. The sequences located at the junctions between each fragment and at the ends of the marker gene are shown, including junction A (SEQ ID NO: 37), junction B (SEQ ID NO: 38), and junction C (SEQ ID NO: 39). The restriction sites used to generate each fragment are indicated at the appropriate junction. The location of the MDV gD and a portion of the gI gene is also given. Numbers in parenthesis ( ) refer to amino acids, and restriction sites in brackets ! indicate the remnants of sites which were destroyed during construction.
FIG. 12A, FIG. 12B and FIG. 12C
Detailed description of the SalI fragment insert in Homology Vector 255-18.B16. The diagram shows the orientation of DNA fragments assembled in the cassette. The origin of each fragment is described in the Materials and Methods section. The sequences located at the junctions between each fragment and at the ends of the marker gene are shown, including junction A (SEQ ID NO: 40), junction B (SEQ ID NO: 41), junction C (SEQ ID NO: 42), junction D (SEQ ID NO: 43), junction E (SEQ ID NO: 44), junction F(SEQ ID NO: 45), junction G (SEQ ID NO: 46), and junction H (SEQ ID NO: 47). The restriction sites used to generate each fragment are indicated at the appropriate junction. The location of the NDV F and lacZ-NDV HN hybrid gene are shown. Numbers in parenthesis ( ) refer to amino acids, and restriction sites in brackets ! indicate the remnants of sites which were destroyed during construction.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a recombinant herpesvirus of turkeys (HVT) which comprises the genomic DNA of herpesvirus of turkey containing foreign DNA not usually present within such genomic DNA. The foreign DNA is inserted within a region of the genomic DNA which is not essential for replication of the herpesvirus of turkeys and DNA corresponding to a promoter is located upstream of the said foreign DNA.
For purposes of this invention, "genomic DNA" means the entire DNA which the naturally occurring herpesvirus of turkeys contains. For purposes of this invention, "foreign DNA" means any DNA that is exogenous to the genomic DNA.
For purposes of this invention, a "promoter" is a specific DNA sequence on the DNA molecule to which the foreign RNA polymerase attaches and at which transcription of the foreign RNA is initiated.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA which encodes a polypeptide. Preferably, the polypeptide is antigenic in the animal into which the recombinant HVT is introduced.
Preferably, this antigenic polypeptide is a linear polymer of more than 10 amino acids linked by peptide bonds which stimulates the animal to produce antibodies.
The invention further provides an insertion site present within BamHI #16 fragment of the herpesvirus of turkeys genome. Preferably, the insertion site is within an open reading frame encoding UL43 protein. Preferably, the insertion site is the XhoI restriction endonuclease site located within an open reading frame encoding UL43 protein.
For purposes of this invention, an "open reading frame" is a segment of DNA which contains codons that can be transcribed into RNA which can be translated into an amino acid sequence and which does not contain a termination codon.
The invention further provides an insertion site within EcoRI #9 fragment of the herpesvirus of turkeys genome. Preferably, the insertion site is XhoI restriction endonuclease site located within the EcoRI #9 fragment.
The invention further provides an insertion site within US2 gene coding region of the herpesvirus of turkeys genome. Preferably, the insertion site is StuI restriction endonuclease site located within the US2 gene coding region.
The invention further provides a recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding a polypeptide which is a detectable marker. Preferably, the detectable marker is E. coli beta-galactosidase. For purposes of this invention, a "polypeptide which is a detectable marker" includes the bimer, trimer and tetramer form of the polypeptide. E. coli .beta.-galactosidase is a tetramer composed of four polypeptides or monomer subunits. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-001, S-HVT-014, or S-HVT-012. The S-HVT-012 herpesvirus has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganism for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A.
The invention further provides a recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding antigenic polypeptide which is from infectious bursal disease virus, Marek's disease virus, Newcastle disease virus, infectious laryngotracheitis virus, or infectious bronchitis virus.
The invention further provides a recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding antigenic polypeptide which is from infectious bursal disease virus. Preferably, antigenic polypeptide is VP2, VP3 or VP4 protein.
The invention further provides a recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding antigenic polypeptide from infectious bursal disease virus and further comprising foreign DNA encoding a polypeptide which is a detectable marker. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-003 or S-HVT-096. The S-HVT-003 herpesvirus has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganism for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding antigenic polypeptide from Marek's disease virus. Preferably, the antigenic polypeptide is Marek's disease virus glycoprotein gB, gA or gD.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gA.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gA and further comprising foreign DNA encoding a polypeptide which is a detectable marker. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-004. The S-HVT-004 herpesvirus has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganism for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A. under ATCC Accession No. VR.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gB. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-045. The S-HVT-045 herpesvirus has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganism for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A.
This invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gB and further comprising foreign DNA encoding Marek's disease virus glycoprotein gA. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-046 or S-HVT-047.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gB, Marek's disease virus glycoprotein gA, and Marek's disease virus glycoprotein gD. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-048.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding antigenic polypeptide from Newcastle disease virus. Preferably, this antigenic polypeptide is Newcastle disease virus fusion (F) protein or Newcastle disease virus hemagglutinin-neuraminidase (HN) protein.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Newcastle disease virus fusion (F) protein and further comprising foreign DNA encoding a recombinant protein, wherein E. coli beta-galactosidase is fused to Newcastle disease virus hemmagglutinin-neuraminidase (HN) protein. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-007.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding antigenic polypeptide from Marek's disease virus and further comprising foreign DNA encoding antigenic polypeptide from Newcastle disease virus.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gB and Marek's disease virus glycoprotein gA and further comprising foreign DNA encoding Newcastle disease virus fusion (F) protein. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-048.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gB and Marek's disease virus glycoprotein gA and further comprising foreign DNA encoding Newcastle disease virus hemagglutinin-neuraminidase (HN) protein. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-049.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gB and Marek's disease virus glycoprotein gA and further comprising foreign DNA encoding Newcastle disease virus fusion (F) protein and Newcastle disease virus hemagglutinin-neuraminidase (HN) protein. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-050.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gB, Marek's disease virus glycoprotein gA, and Marek's disease virus glycoprotein gD and further comprising foreign DNA encoding Newcastle disease virus fusion (F) protein and foreign DNA encoding Newcastle disease virus hemagglutinin-neuraminidase (HN) protein. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-106.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding infectious laryngotracheitis virus glycoprotein gB or infectious laryngotracheitis virus glycoprotein gD. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-051 or S-HVT-052.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding antigenic polypeptide from Marek's disease virus and further comprising foreign DNA encoding antigenic polypeptide from infectious laryngotracheitis virus.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gA and further comprising foreign DNA encoding infectious laryngotracheitis virus glycoprotein gD and foreign DA encoding infectious laryngotracheitis virus glycoprotein gB. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-096.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding Marek's disease virus glycoprotein gB, Marek's disease virus glycoprotein gA, and Marek's disease virus glycoprotein gD and further comprising foreign DNA which encodes infectious laryngotracheitis virus glycoprotein gD, infectious laryngotracheitis virus glycoprotein gB, and E. coli beta-galactosidase. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-104.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding infectious bronchitis virus spike protein or infectious bronchitis virus matrix protein.
The invention further provides recombinant herpesvirus of turkeys whose genomic DNA contains foreign DNA encoding antigenic polypeptide from Marek's disease virus and further comprising foreign DNA encoding infectious bronchitis virus spike protein or infectious bronchitis matrix protein. Preferably, this recombinant herpesvirus of turkeys is designated S-HVT-066.
The inserted foreign DNA is under the control of a promoter. Preferably, the promoter is a herpesvirus promoter. Preferably, the promoter is selected from PRV gX, HSV-1 alpha 4, HCMV immediate early, MDV gB, MDV gD, ILT gB, and ILT gD. For purposes of this invention, the promoters were generated by methods well known to those of skill in the art.
The invention provides for a homology vector for producing a recombinant herpesvirus of turkeys by inserting foreign DNA into the genomic DNA of a herpesvirus of turkeys. The homology vector comprises a double-stranded DNA molecule consisting essentially of a double-stranded foreign DNA not usually present within the herpesvirus of turkeys genomic DNA, with at one end of the foreign DNA, double-stranded herpesvirus of turkeys DNA homologous to genomic DNA located at one side of a site on the genomic DNA which is not essential for replication of the herpesvirus of turkeys, and at the other end of the foreign DNA, double-stranded herpesvirus of turkeys DNA homologous to genomic DNA located at the other side of the same site on the genomic DNA. DNA sequence corresponding to a promoter is located upstream of the foreign DNA and controls the expression of the foreign DNA.
In one embodiment of the invention, the foreign DNA encodes a polypeptide. In one embodiment of the invention, the polypeptide is antigenic in the animal into which the recombinant herpesvirus of turkeys is introduced. Preferably, the antigenic polypeptide is from infectious bursal disease virus, Marek's disease virus, Newcastle disease virus, infectious laryngotracheitis virus, or infectious bronchitis virus. Preferably, the antigenic polypeptide is selected from a group consisting of infectious bursal disease virus VP2 protein, infectious bursal disease virus VP3 protein, infectious bursal disease virus VP4 protein, Marek's disease virus glycoprotein gB, Marek's disease virus glycoprotein gA, Marek's disease virus glycoprotein gD, Newcastle disease virus fusion (F) protein, Newcastle disease virus hemagglutinin-neuraminidase (HN) protein, infectious laryngotracheitis virus glycoprotein gB, infectious laryngotracheitis virus glycoprotein gD, infectious bronchitis virus spike protein, or infectious bronchitis virus matrix protein.
In one embodiment of the invention, the polypeptide is a detectable marker. Preferably, the polypeptide which is a detectable marker is E. coli beta-galactosidase.
In one embodiment of the invention, the double-stranded herpesvirus of turkeys DNA is homologous to DNA sequences present within the BamHI #16 fragment of the herpesvirus of turkeys genome. Preferably, the double-stranded herpesvirus of turkeys DNA is homologous to DNA sequences present within the open reading frame encoding UL 43 protein of the herpesvirus of turkeys genome. Preferably, this homology vector is designated 172-29.31.
For purposes of this invention, a "homology vector" is a plasmid constructed to insert foreign DNA in a specific site on the genome of a herpesvirus of turkeys.
In one embodiment of the invention, the double-stranded herpesvirus of turkeys DNA is homologous to DNA sequences present within the EcoRI #9 fragment of the herpesvirus of turkeys genome. Preferably, this homology vector is designated 172-63.1.
In one embodiment of the invention, the double-stranded herpesvirus of turkeys DNA is homologous to DNA sequences present within the US2 gene coding region of the herpesvirus of turkeys genome. Preferably, this homology vector is designated 435-47.1.
The invention further provides a vaccine which comprises an effective immunizing amount of a recombinant herpesvirus of turkeys of the present invention and a suitable carrier.
Suitable carriers for the herpesvirus of turkeys are well known in the art and include proteins, sugars, etc. One example of such a suitable carrier is a physiologically balanced culture medium containing one or more stabilizing agents such as stabilized, hydrolyzed proteins, lactose, etc.
For purpose of this invention, an "effective immunizing amount" of recombinant herpesvirus of the present invention is within the range of 10.sup.2 to 10.sup.9 PFU/dose.
The present invention also provides a method of immunizing a fowl. For purposes of this invention, this includes immunizing a fowl against infectious bursal disease virus, Marek's disease virus, Newcastle disease virus, infectious laryngotracheitis virus, or infectious bronchitis virus. The method comprises administering to the fowl an effective immunizing dose of the vaccine of the present invention. The vaccine may be administered by any of the methods well known to those skilled in the art, for example, by intramuscular, subcutaneous, intraperitoneal or intravenous injection. Alternatively, the vaccine may be administered intranasally or orally.
The present invention also provides a host cell infected with a recombinant herpesvirus of turkeys. Preferably, the host cell is an avian cell.
For purposes of this invention, a "host cell" is a cell used to propagate a vector and its insert. Infecting the cell was accomplished by methods well known to those skilled in the art, for example, as set forth in DNA TRANSFECTION FOR GENERATING RECOMBINANT HERPESVIRUS in Materials and Methods.
A recombinant herpesvirus of turkeys of the present invention provide a way for distinguishing an animal vaccinated with the vaccine of the present invention from an animal infected with a naturally-occurring, wild-type infectious bursal disease virus, Marek's disease virus, Newcastle disease virus, infectious laryngotracheitis virus, or infectious bronchitis virus. This is possible because recombinant herpesvirus of turkeys contain foreign DNA which encodes a limited number of antigens from the above mentioned viruses that are needed to confer protective immunity to the corresponding pathogens. Consequently, host animals vaccinated with the recombinant herpesvirus of turkeys can be distinguished from those which have been infected with wild-type infectious bursal disease virus, Marek's disease virus, Newcastle disease virus, infectious laryngotracheitis virus, or infectious bronchitis virus by the absence of antigens that are normally present in the wild type viruses.
Methods for constructing, selecting and purifying recombinant herpesvirus of turkeys are detailed below in Materials and Methods.
MATERIALS AND METHODS
PREPARATION OF HERPESVIRUS OF TURKEYS STOCK SAMPLES. Herpesvirus of turkeys stock samples were prepared by infecting tissue culture cells at a multiplicity of infection of 0.01 PFU/cell in Dulbecco's Modified Eagle Medium (DMEM) containing 2 Mm glutamine, 100 units/ml penicillin, 100 units/ml streptomycin (these components are obtained from Irvine Scientific or an equivalent supplier, and hereafter are referred to as complete DME medium) plus 1% fetal bovine serum. After cytopathic effect was complete, the medium and cells were harvested and the cells were pelleted at 3000 rpm for 5 minutes in a clinical centrifuge. Infected cells were resuspended in complete medium containing 20% fetal bovine serum, 10% DMSO and stored frozen at -70.degree. C.
PREPARATION OF HERPESVIRUS OF TURKEY DNA. All manipulations of herpesvirus of turkey (HVT) were made using strain FC-126 (ATCC #584-C). For the preparation of HVT viral DNA from the cytoplasm of infected cells, primary chicken embryo fibroblasts were infected at a MOI sufficient to cause extensive cytopathic effect before the cells overgrew. All incubations were carried out at 39.degree. C. in a humidified incubator with 5% CO.sub.2 in air. Best DNA yields were obtained by harvesting monolayers which were maximally infected, but showing incomplete cell lysis (typically 5-7 days). Infected cells were harvested by scraping the cells into the medium using a cell scraper (Costar brand). The cell suspension was centrifuged at 3000 rpm for 10 minutes at 5.degree. C. in a GS-3 rotor (Sorvall Instruments). The resultant pellet was resuspended in cold PBS (20 ml/Roller Bottle) and subjected to another centrifugation for 10 minutes at 3000 rpm in the cold. After decanting the PBS, the cellular pellet was resuspended in 4 ml/roller bottle of RSB buffer (10 mM Tris pH 7.5, 1 mM EDTA, and 1.5 mM MgCl.sub.2). NP40 (Nonidet P-40.TM.; Sigma) was added to the sample to a final concentration of 0.5% and allowed to incubate on ice for 15 minutes with occasional mixing. The sample was centrifuged for 10 minutes at 3000 rpm in the cold to pellet the nuclei and remove cellular debris. The supernatant fluid was carefully transferred to a 15 ml Corex centrifuge tube. Both EDTA (0.5M pH 8.0) and SDS (sodium dodecyl sulfate; stock 20%) were added to the sample to final concentrations of 5 mM and 1%, respectively. One hundred .mu.l of proteinase-K (10 mg/ml; Boehringer Mannheim) was added per 4 ml of sample, mixed, and incubated at 45.degree. C. for 1-2 hours. After this period, an equal volume of water-saturated phenol was added to the sample and gently mixed by hand. The sample was spun in a clinical centrifuge for 5 minutes at 3000 rpm to separate the phases. NaAc was added to the aqueous phase to a final concentration of 0.3M (stock solution 3M pH 5.2), and the nucleic acid precipitated at -70.degree. C. for 30 minutes after the addition of 2.5 volumes of cold absolute ethanol. DNA in the sample was pelleted by spinning for 20 minutes to 8000 rpm in an HB-4 rotor at 5.degree. C. The supernatant was carefully removed and the DNA pellet washed once with 25 ml of 80% ethanol. The DNA pellet was dried briefly by vacuum (2-3 minutes), and resuspended in 50 .mu.l/roller bottle of infected cells of TE buffer (10 mM Tris pH 7.5, 1 mM EDTA). Typically, yields of viral DNA ranged between 5-10 .mu.g/roller bottle of infected cells. All viral DNA was stored at approximately 10.degree. C.
POLYMERASE FILL-IN REACTION. DNA was resuspended in buffer containing 50 mM Tris pH 7.4, 50 mM KCl, 5 mM MgCl.sub.2, and 400 micromolar each of the four deoxynucleotides. Ten units of Klenow DNA polymerase (BRL) were added and the reaction was allowed to proceed for 15 minutes at room temperature. The DNA was then phenol extracted and ethanol precipitated as above.
DNA SEQUENCING. Sequencing was performed using the USB Sequenase Kit and .sup.35 S-dATP (NEN). Reactions using both the dGTP mixes and the dITP mixes were performed to clarify areas of compression. Alternatively, compressed areas were resolved on formamide gels. Templates were double-stranded plasmid subclones or single stranded M13 subclones, and primers were either made to the vector just outside the insert to be sequenced, or to previously obtained sequence. Sequence obtained was assembled and compared using Dnastar software. Manipulation and comparison of sequences obtained was performed with Superclone and Supersee programs from Coral Software.
MOLECULAR BIOLOGICAL TECHNIQUES. Techniques for the manipulation of bacteria and DNA, including such procedures as digestion with restriction endonucleases, gel electrophoresis, extraction of DNA from gels, ligation, phosphorylation with kinase, treatment with phosphatase, growth of bacterial cultures, transformation of bacteria with DNA, and other molecular biological methods are described by Maniatis et al (1982) and Sambrook et al (1989). The polymerase chain reaction (PCR) was used to introduce restriction sites convenient for the manipulation of various DNAs. The procedures used are described by Innis et al (1990). In general amplified fragments were less than 500 base pairs in size and critical regions of amplified fragments were confirmed by DNA sequencing. Except as noted, these techniques were used with minor variation.
SOUTHERN BLOTTING OF DNA. The general procedure for Southern blotting was taken from Maniatis et al. (1982). DNA was blotted to nitrocellulose filters (S&S BA85) in 20.times. SSC (1.times.ssc=0.15M NaCl, 0.015M sodium citrate, pH 7.0), and prehybridized in hybridization solution consisting of 30% formamide, 1.times. Denhardt's solution (0.02% polyvinylpyrrolidone (PVP), 0.02% bovine serum albumin (BSA), 0.02% Ficoll), 6.times. SSC, 50 mM NaH.sub.2 PO.sub.4, pH 6.8, 200 .mu.g/ml salmon sperm DNA for 4-24 hours at 55.degree. C. Labeled probe DNA was added that had been labeled by nick translation using a kit from Bethesda Research Laboratories (BRL) and one .sup.32 P-labeled nucleotide. The probe DNA was separated from the unincorporated nucleotides by NACS column (BRL) or on a Sephadex G50 column (Pharmacia). After overnight hybridization at 55.degree. C., the filter was washed once with 2.times. SSC at room temperature followed by two washes with 0.1.times. SSC, 0.1% sodium dodecyl sulfate (SDS) for 30 minutes at 55.degree. C. The filter was dried and autoradiographed.
cDNA CLONING PROCEDURE. cDNA cloning refers to the methods used to convert RNA molecules into DNA molecules following state of the art procedures. Applicants' methods are described in (Gubler and Hoffman, 1983). Bethesda Research Laboratories (Gaithersburg, Md.) have designed a cDNA Cloning Kit that is very similar to the procedures used by applicants, and contains a set of reagents and protocols that may be used to duplicate our results.
For cloning virus mRNA species, a host cell line sensitive to infection by the virus was infected at 5-10 plaque forming units per cell. When cytopathic effect was evident, but before total destruction, the medium was removed and the cells were lysed in 10 mls lysis buffer (4 M guanidine thiocyanate, 0.1% antifoam A, 25 mM sodium citrate pH 7.0, 0.5% N-lauroyl sarcosine, 0.1 M beta-mercaptoethanol). The cell lysate was poured into a sterilized Dounce homogenizer and homogenized on ice 8-10 times until the solution was homogenous. For RNA purification, 8 mls of cell lysate were gently layered over 3.5 mls of CsCl solution (5.7 M CsCl, 25 mM sodium citrate pH 7.0) in a Beckman SW41 centrifuge tube. The samples were centrifuged for 18 hrs at 20.degree. C. at 36000 rpm in a Beckman SW41 rotor. The tubes were put on ice and the supernatants from the tubes were carefully removed by aspiration to leave the RNA pellet undisturbed. The pellet was resuspended in 400 .mu.l glass distilled water, and 2.6 mls of guanidine solution (7.5 M guanidine-HCl, 25 mM sodium citrate pH 7.0, 5 mM dithiothreitol) were added. Then 0.37 volumes of 1 M acetic acid were added, followed by 0.75 volumes of cold ethanol and the sample was put at -20.degree. C. for 18 hrs to precipitate RNA. The precipitate was collected by centrifugation in a Sorvall centrifuge for 10 min at 4.degree. C. at 10000 rpm in an SS34 rotor. The pellet was dissolved in 1.0 ml distilled water, recentrifuged at 13000 rpm, and the supernatant saved. RNA was re-extracted from the pellet 2 more times as above with 0.5 ml distilled water, and the supernatants were pooled. A 0.1 volume of 2 M potassium acetate solution was added to the sample followed by 2 volumes of cold ethanol and the sample was put at -20.degree. C. for 18 hrs. The precipitated RNA was collected by centrifugation in the SS34 rotor at 4.degree. C. for 10 min at 10000 rpm. The pellet was dissolved in 1 ml distilled water and the concentration taken by adsorption at A260/280. The RNA was stored at -70.degree. C.
mRNA containing polyadenylate tails (poly-A) was selected using oligo-dT cellulose (Pharmacia #27 5543-0). Three mg of total RNA was boiled and chilled and applied to a 100 mg oligo-dT cellulose column in binding buffer (0.1 M Tris pH 7.5, 0.5 M LiCl, 5 mM EDTA pH 8.0, 0.1% lithium dodecyl sulfate). The retained poly-A.sup.+ RNA was eluted from the column with elution buffer (5 mM Tris pH 7.5, 1 mM EDTA pH 8.0, 0.1% sodium dodecyl sulfate). This mRNA was reapplied to an oligo-dT column in binding buffer and eluted again in elution buffer. The sample was precipitated with 200 mM sodium acetate and 2 volumes cold ethanol at -20.degree. C. for 18 hrs. The RNA was resuspended in 50 .mu.l distilled water.
Ten .mu.g poly-A.sup.+ RNA was denatured in 20 mM methyl mercury hydroxide for 6 min at 22.degree. C. .beta.-mercaptoethanol was added to 75 mM and the sample was incubated for 5 min at 22.degree. C. The reaction mixture for first strand cDNA synthesis in 0.25 ml contained 1 .mu.g oligo-dT primer (P-L Bio-chemicals) or 1 .mu.g synthetic primer, 28 units placental ribonuclease inhibitor (Bethesda Research Labs #5518SA), 100 mM Tris pH 8.3, 140 mM KCl, 10 mM MgCl.sub.2, 0.8 mM DATP, dCTP, dGTP, and dTTP (Pharmacia), 100 microcuries .sup.32 P-labeled dCTP (New England Nuclear #NEG-013H), and 180 units AMV reverse transcriptase (Molecular Genetics Resources #MG 101). The reaction was incubated at 42.degree. C. for 90 min, and then was terminated with 20 mM EDTA pH 8.0. The sample was extracted with an equal volume of phenol/chloroform (1:1) and precipitated with 2 M ammonium acetate and 2 volumes of cold ethanol -20.degree. C. for 3 hrs. After precipitation and centrifugation, the pellet was dissolved in 100 .mu.l distilled water. The sample was loaded onto a 15 ml G-100 Sephadex column (Pharmacia) in buffer (100 mM Tris pH 7.5, 1 mM EDTA pH 8.0, 100 mM NaCl). The leading edge of the eluted DNA fractions was pooled, and DNA was concentrated by lyophilization until the volume was about 100 .mu.l, then the DNA was precipitated with ammonium acetate plus ethanol as above.
The entire first strand sample was used for second strand reaction which followed the Gubler and Hoffman (1983) method except that 50 .mu.g/ml dNTP's, 5.4 units DNA polymerase I (Boerhinger Mannheim #642-711), and 100 units/ml E. coli DNA ligase (New England Biolabs #205) in a total volume of 50 microliters were used. After second strand synthesis, the CDNA was phenol/chloroform extracted and precipitated. The DNA was resuspended in 10 .mu.l distilled water, treated with 1 .mu.g RNase A for 10 min at 22.degree. C., and electrophoresed through a 1% agarose gel (Sigma Type II agarose) in 40 mM Tris-acetate buffer pH 6.85. The gel was stained with ethidium bromide, and DNA in the expected size range was excised from the gel and electroeluted in 8 mM Tris-acetate pH 6.85. Electroeluted DNA was lyophilized to about 100 microliters, and precipitated with ammonium acetate and ethanol as above. The DNA was resuspended in 20 .mu.l water.
Oligo-dC tails were added to the DNA to facilitate cloning. The reaction contained the DNA, 100 mM potassium cacodylate pH 7.2, 0.2 mM dithiothreitol, 2 mM CaCl.sub.2, 80 .mu.moles dCTP, and 25 units terminal deoxynucleotidyl transferase (Molecular Genetic Resources #S1001) in 50 .mu.l. After 30 min at 37.degree. C., the reaction was terminated with 10 mM EDTA, and the sample was phenol/chloroform extracted and precipitated as above.
The dC-tailed DNA sample was annealed to 200 ng plasmid vector pBR322 that contained oligo-dG tails (Bethesda Research Labs #5355 SA/SB) in 200 .mu.l of 0.01 M Tris pH 7.5, 0.1 M NaCl, 1 mM EDTA pH 8.0 at 65.degree. C. for 2 min and then 57.degree. C. for 2 hrs. Fresh competent E. coli DH-1 cells were prepared and transformed as described by Hanahan (1983) using half the annealed cDNA sample in twenty 200 .mu.l aliquots of cells. Transformed cells were plated on L-broth agar plates plus 10 .mu.g/ml tetracycline. Colonies were screened for the presence of inserts into the ampicillin gene using Ampscreen.backslash.(Bethesda Research Labs #5537 UA), and the positive colonies were picked for analysis.
DNA TRANSFECTION FOR GENERATING RECOMBINANT HERPESVIRUS. The method is based upon the polybrene-DMSO procedure of Kawai and Nishizawa (1984) with the following modifications. Generation of recombinant HVT virus is dependent upon homologous recombination between HVT viral DNA and the plasmid homology vector containing the desired foreign DNA flanked by the appropriate herpesvirus cloned sequences. Transfections were carried out in 6 cm plates (Corning plastic) of 50% confluent primary chick embryo fibroblast (CEF) cells. The cells were plated out the day before in CEF growth media (1.times. F10/199, 5% fetal calf serum, 2% glutamine, 1% non-essential amino acids, and 2% penicillin/streptomycin) containing 4 .mu.g/ml polybrene (stock 4 mg/ml in 1.times.HBSS). For cotransfections into CEF cells, 5 .mu.g of the plasmid homology vector was mixed with 5 .mu.g of intact HVT DNA, and suspended in 1 ml of CEF media containing 30 .mu.g/ml polybrene (stock 4 mg/ml in 1.times. HBSS). The DNA-polybrene suspension (1 ml) was then added to a 6 cm plate of CEF cells from which the media had been aspirated, and incubated at 39.degree. C. for 30 minutes. The plates were rocked periodically during this time to redistribute the inoculum. After this period, 4 ml of CEF growth media was added directly to wash plate, and incubated an additional 2.5 hours at 39.degree. C. At this time, the media was removed from each plate, and the cells shocked with 2 ml of 30% DMSO (Dimethyl Sulfoxide, J.T. Baker Chemical Co.) in 1.times. HBSS for 4 minutes at room temperature. The 30% DMSO was carefully removed and the monolayers washed once with 1.times. HBSS at room temperature. The cells were then incubated at 39.degree. C. after the addition of 5 mls of CEF growth media. The next day, the media was changed to remove any last traces of DMSO and to stimulate cell growth. Cytopathic effect from the virus becomes apparent within 6 days. Generation of a high titer stock (80%-90% CPE) can usually be made within 1 week from this date. HVT stock samples were prepared by resuspending the infected cells in CEF growth media containing 20% fetal calf serum, 10% DMSO and stored at -70.degree. C.
PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The ability to generate herpesviruses by cotransfection of cloned overlapping subgenmoic fragments has been demonstrated for pseudorabies virus (Zijl et al., 1988). If deletions and/or insertions are engineered directly into the subgenomic fragments prior to the cotransfection, this procedure results in a high frequency of viruses containing the genomic alteration, greatly reducing the amount of screening required to purify the recombinant virus. We have used this procedure to construct recombinant HVT.
A library of subclones containing overlapping HVT subgenomic fragments was generated as follows. HVT DNA was obtained from the American Type Culture Collection (FC-126 ("Calnek")). It was sheared and then size selected on a glycerol gradient as described by van Zijl et al.,(1988) with 40-50 kb fragments chosen as the insert population. The pooled fractions were diluted twofold with TE, one-tenth volume of 3M NaAc and 2.5 volumes of ethanol were added, and the DNA was precipitated at 30K rpm in a Beckman SW41 rotor for 1 hr. The sheared fragments were given blunt ends by initial treatment with T4 DNA polymerase, using low DNTP concentrations to promote 3' overhang removal, followed by treatment with Klenow polymerase to fill in recessed 3' ends. These insert fragments were then ligated to a pWE15 (Strategene) cosmid vector, which had been digested with BamHI, treated with calf intestinal phosphatase, and made blunt by treatment with Klenow polymerase. The ligated mixture was then packaged using Gigapack XL packaging extracts (Stratagene). Ligation and packaging was as recommended by the manufacturer.
Published restriction maps for the enzymes BamHI, HindIII, and XhoI permitted the use of subcloned fragments as specific probes to screen the cosmid library for subclones spanning the genome. Probes were generated from subcloned restriction fragments. The fragments were then labeled using a non-radioactive system (Genius, Boehringer Mannheim). Screening was facilitated by picking colonies to media followed by growth overnight. Sets of five filters and a master plate were stamped from microtiter dish and again grown overnight. Glycerol was added to the wells to 15% and the plates were frozen at -20.degree. C. to provide stock cultures of each colony. Filters were BioRad Colony Lift Membranes and were treated and hybridized per manufacturer's instructions, and washed in 0.1.times. SSC, 0.1% SDS, 65.degree. C. Clones which hybridized with the non-radioactive probe were detected according to the Genius kit directions.
Colonies were selected for further analysis on the basis of their hybridization to two or more of the specific probes. These were then digested with BamHI, and compared to published maps of HVT (Buckmaster et al., 1988). The three cosmids (407-32.2C3,407-32.1G7, and 407-32.5G6) were obtained in this manner. A detailed description of each clone is given below. It was found that chloramphenicol amplification (Maniatis et al.,1982) was necessary to achieve reasonable yields of DNA from these clones. In addition, one cosmid clone (407-32.5G6) was unstable and had to be grown from the original frozen stock in order to obtain satisfactory DNA preparations.
The pWE15 vector allows the inserts to be excised with NotI. However, four NotI sites are present in the HVT genome, so that inserts spanning these sites cannot be excised with NotI. Two of the NotI sites are present in the BamHI #2 fragment of HVT, this fragment was cloned directly in pSP64. The other two sites are present in the unique short region within the BamHI #1 fragment. This fragment was cloned directly in the pWE15 vector. The three sheared cosmids and the two BamHI fragments cover all but a small portion of the ends of the HVT genome. Because these regions are repeated in the internal portions of the genome, all of the genetic information is available.
A StuI site within the HVT US2 gene was established as a useful site for foreign DNA insertion utilizing the HOMOLOGOUS RECOMBINATION PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUSES (see Example 6). The HVT US2 gene is located within the BamHI #1 fragment which contains five Stul sites. To facilitate the use of this site for insertion of foreign DNA by the StuI site within the US2 gene was converted to a unique HindIII site. This was accomplished by partially digesting the BamHI #1 subclone with StuI, and then inserting a 10 kb fragment conferring kanomycin resistance (Neo.sup.R) into the site using HindIII linkers. The kanomycin resistance gene allowed positive selection of recombinant clones. The Neo.sup.R fragment was removed by digestion with HindIII followed by religation generating clone 430-84.215.
DNA was prepared for reconstruction experiments by restriction digestion with enzymes which cut the subclones outside or flanking the HVT insertions. In some instances, one cosmid in a reconstruction was used undigested. Digested DNAs were extracted once with phenol and precipitated with ethanol. DNA was resuspended at a concentration of 0.5 to 1 ug/ml. Viral reconstruction experiments were performed using Lipofectin (BRL) to mediate transfection. Two to three micrograms each of subclone were added to 0.5 ml of MEM media (Earle's salts) supplemented with 1% non-essential amino acids and 2% penicillin/Streptomysin (MEM+). Controls consisted of MEM+ with no DNA, with several ug of HVT DNA, or with 4 out of 5 of the subclones. Separately, 30 .mu.l of the Lipofectin were added to another 0.5 ml. of MEM+. These two mixtures were then combined and incubated at RT for 15 minutes.
Chick embryo fibroblast (CEF) cells were prepared for transfection in the following manner. CEFs (Spafas) were grown in 6 well dishes at 39.degree. C. in F10/M199 (1:1) media containing 1% non-essential amino acids, 2% penicillin/streptomycin, and 5% fetal calf serum (CEF+). Cells were transfected at a confluence of 90-95%. For transfection, wells were aspirated and rinsed 3 times with MEM+, and then incubated 4 hours at 39.degree. C. with the 1 ml lipofectin/DNA mixture above. One ml more of CEF+ was then added to the wells, and cells were incubated overnight and fed with CEF+. Plates were then examined daily for the appearance of plaques.
Lipofectin with control HVT DNA resulted in the appearance of plaques within 5 days. When only four of the five subclones were used, no plaques were obtained. When the five overlapping genomic fragments of HVT were used to reconstruct the virus, plaques appeared anywhere from 5 to 19 days after the initial lipofection. In the case of plaques appearing late, plaques were not initially seen on the infected monolayer, and it was only after passaging the monolayer and replating on a larger surface that plaques appeared. After passaging, plaques generally appeared within 3 days. Recombinant viruses were plaque purified approximately three and then analyzed for insertion of foreign DNAs.
BLUOGAL SCREEN FOR RECOMBINANT HERPESVIRUS. When the foreign gene encoded the enzyme .beta.-galactosidase, the plaques that contained the gene were visualized more easily. The chemical Bluogal.TM. (Bethesda Research Labs) was incorporated at the level of 200-300 .mu.g/ml into the agarose overlay during the plaque assay, and the plaques that expressed active .beta.-galactosidase turned blue. The blue plaques were then picked and purified by further blue plaque isolations. Other foreign genes were inserted by homologous recombination such that they replaced the .beta.-galactosidase gene; in this instance non-blue plaques were picked for purification of the recombinant virus.
SCREEN FOR FOREIGN GENE EXPRESSION IN RECOMBINANT HVT USING BLACK PLAQUE ASSAYS. To analyze expression of foreign antigens expressed by recombinant HVT viruses, monolayers of CEF cells are infected with recombinant HVT, overlaid with nutrient agarose media and incubated for 4-5 days at 39.degree. C. Once plaques have developed, the agarose overlay is removed from the dish, the monolayer rinsed 1.times. with PBS, fixed with 100% methanol for 10 minutes at room temperature and the cells air dried. After re-hydrating the plate with PBS, the primary antibody is diluted to the appropriate dilution with PBS and incubated with the cell monolayer for 2 hours to overnight at room temperature. Unbound antibody is then removed from the cells by washing three times with PBS at room temperature. An alkaline phosphatase conjugated secondary antibody is diluted with PBS and incubated with the cells for 2 hours at room temperature. Unbound secondary antibody is then removed by washing the cells three times with PBS at room temperature. Next, the monolayer is rinsed in color development buffer (100 mM Tris pH 9.5/100 mM NaCl/5 mM MgCl2), and then incubated 10 minutes to overnight at room temperature with freshly prepared substrate solution (0.3 mg/ml Nitro Blue tetrazolium+0.15 mg/ml 5-Bromo-4-Chloro-3-Indolyl Phosphatase in color development buffer.) Finally, the reaction is stopped by replacing the substrate solution with TE (10 mM Tris, pH7.5/1 mM EDTA). Plaques expressing the correct antigen will stain black.
PLAQUE HYBRIDIZATION PROCEDURE FOR ASSESSING THE PURITY OF RECOMBINANT HVT STOCKS. When no suitable immunological reagent exists to detect the presence of a particular antigen in a recombinant HVT virus, plaque hybridization can be used to assess the purity of a stock. Initially, CEF cell monolayers are infected with various dilutions of the viral stocks to give .noteq.50-100 plaques/10 cm.dish, overlaid with nutrient agarose media and incubated for 4-5 days at 39.degree. C. Once plaque development occurs, the position of each plaque is marked on bottom of the dish. The agarose overlay is then removed, the plate washed with PBS, and the remaining CEF monolayer is transferred to a NC membrane or BioRad nylon membrane pre-wetted with PBS (making note of the membrane position relative to the dish). Cells contained on the NC membranes are then lysed by placing the membranes in 1.5 mls of 1.5M NaCl and 0.5M NaOH for five minutes. The membranes are neutralized by placing them in 1.5 mls of 3M Sodium acetate (pH 5.2) for five minutes. DNA from the lysed cells is then bound to the NC membranes by baking at 80.degree. C. for one hour. After this period the membranes are prehybridized in a solution containing 6.times. SSC, 3% skim milk, 0.5% SDS, (.+-.) salmon sperm DNA (50 .mu.g/ml) for one hour at 65.degree. C. Radio-labeled probe DNA (alpha 32P-dCTP) is then added and the membranes incubated at 65.degree. C. overnight (.noteq.12 hours). After hybridization the NC membranes are washed two times (30 minutes each) with 2.times. SSC at 65.degree. C., followed by two additional washes at 65.degree. C. with 0.5.times. SSC. The NC membranes are then dried and exposed to X-ray film (Kodak X-OMAT,AR) at -70.degree. C. for 12 hours. Positive signals are then aligned with the position of the plaques on the dish and purity of the stock is recorded as the percentage of positive plaques over the total.
CONSTRUCTION OF HOMOLOGY VECTOR FOR INSERTION OF THE BETA-GALACTOSIDASE GENE INTO HVT US2 GENE. The beta-galactosidase (lacz) gene was inserted into the HVT EcoRI # 7 fragment at the unique StuI site. The marker gene is oriented in the same direction as the US2 gene. A detailed description of the marker gene is given in FIG. 7. It is constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources with the synthetic DNA sequences indicated in FIG. 7. Fragment 1 is an approximately 413 base pair SalI to BamHI restriction sub-fragment of the PRV BamHI restriction fragment 10 (Lomniczi et al., 1984). Fragment 2 is an approximately 3010 base pair BamHI to PvuII restriction fragment of plasmid pJF751 (Ferrari et al., 1985). Fragment 3 is an approximately 754 base pair NdeI to SalI restriction sub-fragment of the PRV BamHI restriction fragment #7 (Lomniczi et al., 1984).
SUBGENOMIC CLONE 172-07.BA2. Plasmid 172-07.BA2 was constructed for the purpose of generating recombinant HVT. It contains an approximately 25,000 base pair region of genomic HVT DNA. It may be used in conjunction with other subgenomic clones according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS for the construction of recombinant HVT. This plasmid may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining two restriction fragments from the following sources. The first fragment is an approximately 2999 base pair BamHI to BamHI restriction fragment of pSP64 (Promega). The second fragment is the approximately 25,000 base pair BamHI #2 fragment of HVT (Buckmaster et al., 1988).
HOMOLOGY VECTOR 172-29.31. The plasmid 172-29.31 was constructed for the purpose of inserting foreign DNA into HVT. It contains a unique XhoI restriction enzyme site into which foreign DNA may be inserted. When a plasmid containing a foreign DNA insert at the XhoI site is used according to the DNA COTRANSFECTION FOR GENERATING RECOMBINANT HERPESVIRUSES or the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS a virus containing the foreign DNA will result. This plasmid may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining two restriction fragments from the following sources. The first fragment is an approximately 2999 base pair BamHI to BamHI restriction fragment of pSP64 (Promega). The second fragment is the approximately 3300 base pair BamHI #16 fragment of HVT (Buckmaster et al., 1988). The complete sequence of the BamHI #16 fragment is given in SEQ ID NO:3. Note that the fragment was cloned such that the UL43 ORF is in the opposite transcriptional orientation to the pSP64 .beta.-lacatamase gene.
HOMOLOGY VECTOR 172-63.1. The plasmid 172-63.1 was constructed for the purpose of inserting foreign DNA into HVT. It contains a unique XhoI restriction enzyme site into which foreign DNA may be inserted. When a plasmid containing a foreign DNA insert at the XhoI site is used according to the DNA COTRANSFECTION FOR GENERATING RECOMBINANT HERPESVIRUSES or the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS a virus containing the foreign DNA will result. This plasmid may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining two restriction fragments from the following sources. The first fragment is an approximately 2999 base pair EcoRI to EcoRI restriction fragment of pSP64 (Promega). The second fragment is the approximately 5500 base pair EcoRI #9 fragment of HVT. Note that the EcoRI fragment was cloned such that the unique XhoI site is closest to the unique HindIII site in the pSP64 vector.
HOMOLOGY VECTORS 255-18.B16. The plasmid 255-18.B16 was constructed for the purpose of inserting the NDV HN and F genes into HVT. The NDV HN and F genes were inserted as a SalI fragment into the homology vector 172-29.31 at the XhoI site. The NDV HN and F genes were inserted in the same transcriptional orientation the UL43 ORF in the parental homology vector. A detailed description of the SalI fragment is shown in FIG. 12. The inserted SalI fragment may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources with the synthetic DNA sequences indicated in FIG. 12. Fragment 1 is an approximately 416 base pair SalI to BamHI restriction sub-fragment of the PRV BamHI restriction fragment 10 (Lomniczi et al., 1984). Fragment 2 is an approximately 3009 base pair BamHI to PvuII fragment of the plasmid pJF751 (Ferrari et al., 1985). Fragment 3 is an approximately 1200 base pair AvaII to EcoRI restriction fragment of full length NDV HN cDNA. Fragment 4 is an approximately 179 base pair EcoRI to PvuII restriction fragment of the plasmid pSP64 (Promega). Fragment 5 is an approximately 357 base pair SmaI to BamHI restriction sub-fragment of the HSV-l BamHI restriction fragment N. Fragment 6 is an approximately 1812 base pair BamHI to PstI restriction fragment of the full length NDV F cDNA. Fragment 7 is an approximately 235 base pair PstI to ScaI restriction fragment of the plasmid pBR322.
SUBGEMOMIC CLONE 378-50.BA1. Cosmid 378-50.BA1 was constructed for the purpose of generating recombinant HVT. It contains an approximately 29,500 base pair region of genomic HVT DNA. It may be used in conjunction with other subgenomic clones according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS for the construction of recombinant HVT. This cosmid may be constructed by joining two restriction fragments from the following sources. The first fragment is an approximately 8164 base pair BamHI to BamHI restriction fragment of pWE15 (Stratagene). The second fragment is the approximately 29,500 base pair BamHI #1 fragment of HVT (Buckmaster et al., 1988).
SUBGEMOMIC CLONE 407-32.1C1. Cosmid 407-32.1C1 was constructed for the purpose of generating recombinant HVT. It contains an approximately 38,850 base pair region of genomic HVT DNA (see FIG. 8). This region includes BamHI fragments 11, 7, 8, 21, 6, 18, approximately 1250 base pairs of fragment 13, and approximately 6,700 base pairs of fragment 1. It may be used in conjunction with other subgenomic clones according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS for the construction of recombinant HVT. This cosmid maybe constructed as described above in the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS. It was isolated from the sheared DNA library by screening with the probes P1 and P4 (described in FIG. 8). A bacterial strain containing this cosmid has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganisms for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A.
SUBGEMOMIC CLONE 407-32.2C3. Cosmid 407-32.2C3 was constructed for the purpose of generating recombinant HVT. It contains an approximately 40,170 base pair region of genomic HVT DNA (see FIG. 8). This region includes BamHI fragments 10, 14, 19, 17, 5, and approximately 2,100 base pairs of fragment 2. It may be used in conjunction with other subgenomic clones according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS for the construction of recombinant HVT. This cosmid may be constructed as described above in the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS. It was isolated from the sheared DNA library by screening with the probes P1 and P2 (described in FIG. 8). A bacterial strain containing this cosmid has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganisms for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A.
SUBGEMOMIC CLONE 407-32.5G6. Cosmid 407-32.5G6 was constructed for the purpose of generating recombinant HVT. It contains an approximately 40,000 base pair region of genomic HVT DNA (see FIG. 8). This region includes BamHI fragments 9, 3, 20, 12, 16, 13, approximately 1,650 base pairs of fragment 2, and approximately 4,000 base pairs of fragment 11. It may be used in conjunction with other subgenomic clones according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS for the construction of recombinant HVT. This cosmid may be constructed as described above in the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS. It was isolated from the sheared DNA library by screening with the probes P2 and P3 (described in FIG. 8). A bacterial strain containing this cosmid has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganisms for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A.
HOMOLOGY VECTOR 435-47.1. The plasmid 435-47.1 was constructed for the purpose of inserting foreign DNA into HVT. It contains a unique HindIII restriction enzyme site into which foreign DNA may be inserted. When a plasmid containing a foreign DNA insert at the HindIII site is used according to the DNA COTRANSFECTION FOR GENERATING RECOMBINANT HERPESVIRUSES or the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS a virus containing the foreign DNA will result. This plasmid may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining two restriction fragments from the following sources. The first fragment is an approximately 2999 base pair EcoRI to EcoRI restriction fragment of pSP64 (Promega). The second fragment is the approximately 7300 base pair EcoRI #7 fragment of HVT. Note that the HindIII site of the pSP64 vector was removed by digesting the subclone with HindIII followed by a Klenow fill in reaction and religation. A synthetic HindIII linker (CAAGCTTG) was then inserted into the unique StuI site of the EcoRI #7 fragment.
SUBGEMOMIC CLONE 437-26.24. Plasmid 437-26.24 was constructed for the purpose of generating recombinant HVT. It contains an approximately 13,600 base pair region of genomic HVT DNA. It may be used in conjunction with other subgenomic clones according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS for the construction of recombinant HVT. This plasmid may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining two restriction fragments from the following sources. The first fragment is an approximately 2970 base pair HindIII to BamHI restriction fragment of pSP64 (Promega). The second fragment is the approximately 13,600 base pair BamHI to StuI sub-fragment of the BamHI #2 fragment of HVT (Buckmaster et al., 1988). Note that the BamHI #2 fragment contains five StuI sites, the site utilized in this subcloning was converted to a HindIII site as described in the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS.
SUBGEMOMIC CLONE 437-26.26. Plasmid 437-26.26 was constructed for the purpose of generating recombinant HVT. It contains an approximately 15,300 base pair region of genomic HVT DNA. It may be used in conjunction with other subgenomic clones according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS for the construction of recombinant HVT. This plasmid may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining two restriction fragments from the following sources. The first fragment is an approximately 2970 base pair HindIII to BamHI restriction fragment of pSP64 (Promega). The second fragment is the approximately 15,300 base pair BamHI to StuI sub-fragment of the BamHI #2 fragment of HVT (Buckmaster et al., 1988). Note that the BamHI #2 fragment contains five StuI sites, the site utilized in this subcloning was converted to a HindIII site as described in the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS.
HOMOLOGY VECTORS 456-18.18 and 456-17.22. The plasmids 456-18.18 and 456-17.22 were constructed for the purpose of inserting the MDV gA and gB genes into HVT. The MDV genes were inserted as a cassette into the homology vector 435-47.1 at the unique HindIII site. The MDV genes were inserted at the blunt ended HindIII site as a blunt ended PstI to EcoRI fragment (see FIG. 10). The HindIII and EcoRI sites were blunted by the Klenow fill in reaction. The PstI site was blunted by the T4 DNA polymerase reaction. Note that the MDV cassette was inserted in both orientations. Plasmid 456-18.18 contains the MDV genes inserted in the opposite transcriptional orientation to the US2 gene in the parental homology vector. Plasmid 456-17.22 contains the MDV genes inserted in the same transcriptional orientation as the US2 gene in the parental homology vector. A detailed description of the MDV cassette is given in FIG. 10. It may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources with the synthetic DNA sequences indicated in FIG. 10. Fragment 1 is an approximately 2178 base pair PvuII to EcoRV restriction sub-fragment of the MDV EcoRI 6.9 KB genomic restriction fragment (Ihara et al., 1989). Fragment 2 is an approximately 3898 base pair SalI to EcoRI genomic MDV fragment (Ross, et al., 1989).
HOMOLOGY VECTOR 528-03.37. The plasmid 528-03.37 was constructed for the purpose of inserting the infectious laryngotracheitis (ILT) virus gD gene into HVT. The gD gene followed by the PRV gX poly adenylation signal was inserted as a cassette into the homology vector 435-47.1 at the unique HindIII site. The cassette may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources. The first fragment is an approximately 2060 base pair EcoRI to BclI restriction sub-fragment of the ILT KpnI genomic restriction fragment #8 (10.6 KB). The second fragment is an approximately 754 base pair NdeI to SalI restriction sub-fragment of the PRV BamHI restriction fragment #7 (Lomniczi et al., 1984). Note that the fragments are oriented such that BclI and NdeI sites are contiguous.
HOMOLOGY VECTOR 528-11.43. The plasmid 528-11.43 was constructed for the purpose of inserting the infectious laryngotracheitis (ILT) virus gB gene (A. M. Grifin, 1991) into HVT. The gB gene was inserted as an EcoRI fragment into the homology vector 435-47.1 at the unique HindIII site. The gB gene was inserted at the blunt ended HindIII site as a blunt ended EcoRI fragment. The HindIII and EcoRI sites were blunted by the Klenow fill in reaction. The gB gene was inserted in the same transcriptional orientation as the US2 gene in the parental homology vector. The EcoRI fragment may be obtained as a 3.0 KB ILT virus genomic fragment.
HOMOLOGY VECTOR 518-46.B3. The plasmid 518-46.B3 was constructed for the purpose of inserting foreign DNA into HVT. It contains a unique HindIII restriction enzyme site into which foreign DNA may be inserted. When a plasmid containing a foreign DNA insert at the HindIII site is used according to the DNA COTRANSFECTION FOR GENERATING RECOMBINANT HERPESVIRUSES or the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS a virus containing the foreign DNA will result. This plasmid may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining three restriction fragments from the following sources. The first fragment is an approximately 1649 base pair PvuI to SalI restriction fragment of pSP64 (Promega). The second fragment is an approximately 1368 base pair PvuI to SalI restriction fragment of pSP65 (Promega). The third fragment is the approximately 3400 base pair XhoI to XhoI fragment of plasmid 437-47.1.
HOMOLOGY VECTOR 535-70.3. The plasmid 535-70.3 was constructed for the purpose of inserting the MDV gB, and gA genes and the NDV F gene into HVT. The F gene was inserted as a cassette into homology vector 456-17.22 at the HindIII site located between the MDV gA and gB genes (see FIG. 10A junction B). The F gene is under the control of the HCMV immediate early promoter and followed by the HSV-1 TK poly adenylation signal. The F gene was inserted in the same transcriptional orientation as the US2 gene in the parental homology vector. The cassette may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources. The first fragment is an approximately 1191 base pair PstI to AvaII restriction sub-fragment of the HCMV genomic XbaI E fragment (D. R. Thomsen, et al., 1981). The second fragment is an approximately 1812 base pair BamHI to PstI restriction fragment of the full length NDV F cDNA clone (B1 strain). The last fragment is an approximately 784 base pair SmaI to SmaI restriction sub-fragment of the HSV-1 BamHI restriction fragment Q (McGeoch, et al., 1985).
HOMOLOGY VECTOR 549-24.15. The plasmid 549-24.15 was constructed for the purpose of inserting the MDV gB, and gA genes and the NDV HN and F genes into HVT. The HN and F genes were inserted as a cassette into homology vector 456-17.22 at the HindIII site located between the MDV gA and gB genes (see FIG. 10A junction B). The HN and F genes are under the control of the PRV gpX and HCMV immediate early promoters respectively. The HN and F genes are followed by the PRV gX poly and HSV-1 TK adenylation signals respectively. The cassette may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources. The first fragment is an approximately 413 base pair SalI to BamHI restriction sub-fragment of the PRV BamHI fragment #10 (Lomniczi, et al., 1984). The second fragment is an approximately 1811 base pair AvaII to NaeI restriction fragment of the full length NDV HN cDNA clone (B1 strain). The third fragment is an approximately 754 base pair NdeI to SalI restriction sub-fragment of the PRV BamHI restriction fragment #7 (Lomniczi, et al., 1984). The fourth fragment is an approximately 1191 base pair PstI to AvaII restriction sub-fragment of the HCMV genomic XbaI E fragment (D. R. Thomsen, et al., 1981). The fifth fragment is an approximately 1812 base pair BamHI to PstI restriction fragment of the full length NDV F cDNA clone (B1 strain). The last fragment is an approximately 784 base pair SmaI to SmaI restriction sub-fragment of the HSV-1 BamHI restriction fragment Q (McGeoch, et al., 1985).
HOMOLOGY VECTOR 549-62.10. The plasmid 549-62.10 was constructed for the purpose of inserting the MDV gB, and gA genes and the NDV HN gene into HVT. The HN gene was inserted as a cassette into homology vector 456-17.22 at the HindIII site located between the MDV gA and gB genes (see FIG. 10A junction B). The HN gene is under the control of the PRV gpX promoter and followed by the PRV gX poly adenylation signal. The HN gene was inserted in the same transcriptional orientation as the US2 gene in the parental homology vector. The cassette may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources. The first fragment is an approximately 413 base pair SalI to BamHI restriction sub-fragment of the PRV BamHI fragment #10 (Lomniczi, et al., 1984). The second fragment is an approximately 1811 base pair AvaII to NaeI restriction fragment of the full length NDV HN CDNA clone (B1 strain). The last fragment is an approximately 754 base pair NdeI to SalI restriction sub-fragment of the PRV BamHI restriction fragment #7 (Lomniczi, et al., 1984).
SUBGENOMIC CLONE 550-60.6 Plasmid 550-60.6 was constructed for the purpose of generating recombinant HVT. It contains an approximately 12,300 base pair region of genomic HVT DNA. It may be used in conjunction with other subgenomic clones according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM OVERLAPPING SUBGENOMIC FRAGMENTS for the construction of recombinant HVT. This plasmid may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining two restriction fragments from the following sources. The first fragment is an approximately 4176 base pair EcoRV to BamHI restriction fragment of pBR322. The second fragment is the approximately 12,300 base pair sub-fragment of the BamHI #2 fragment of HVT (Buckmaster et al., 1988). This fragment was generated in the following manner. Plasmid 437-26.26 was linearized with HindIII and then resected with the ExoIII Mung Bean Deletion Kit (Stratagene). Samples from the 3 and 4 minute reactions were combined and digested with BamHI resulting in a population of fragments containing the desired 12,300 base pair sub-fragment. This population was cloned into the pBR322 fragment and the resulting clones were screened for the appropriate size and restriction map. Fortuitously the resected sub-fragment that generated clone 550-60.6 ended in the nucleotides GG which generated a second BamHI site when ligated to the EcoRV site (ATCC) of pBR322. A bacterial strain containing this plasmid has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganisms for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A.
HOMOLOGY VECTORS 566-41.5. The plasmid 566-41.5 was constructed for the purpose of inserting the MDV gA, gB and gD genes into HVT. The MDV gD gene was inserted as a HindIII fragment into the homology vector 456-17.22 at the HindIII site located between MDV gA and gB (see FIG. 10). The MDV gene was inserted in the same transcriptional orientation as gA and gB in the parental homology vector. A detailed description of the HindIII fragment containing the MDV gD gene is shown in FIG. 11. Note that a herpesvirus polyadenation signal was added to the gD gene cassette. The inserted HindIII fragment may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources with the synthetic DNA sequences indicated in FIG. 11. Fragment 1 is an approximately 784 base pair SmaI to SmaI restriction sub-fragment of the HSV-1 BamHI restriction fragment Q (McGeoch et al., 1988). Note that this fragment is oriented such that the polyadenylation sequence (AATAAA) is located closest to junction B. Fragment 2 is an approximately 2177 base pair SalI to NcoI sub-fragment of the MDV BglII 4.2 KB genomic restriction fragment (Ross, et al., 1991).
HOMOLOGY VECTOR 567-72.1D. The plasmid 567-72.1D was constructed for the purpose of inserting the MDV gB, gA, and gD genes and the infectious bronchitis virus (IBV) matrix and spike genes into HVT. The IBV genes were inserted as a cassette into homology vector 566-41.5 at the unique NotI site located upstream of the MDV gD gene (see FIG. 11B junction C). The IBV spike and matrix genes are under the control of the HCMV immediate early and PRV gpX promoters respectively. The IBV spike and matrix genes are followed by the HSV-1 TK and PRV gX poly adenylation signals respectively. The IBV genes were inserted in the same transcriptional orientation as the US2 gene in the parental homology vector. The cassette may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources. The first fragment is an approximately 413 base pair SalI to BamHI restriction sub-fragment of the PRV BamHI fragment #10 (Lomniczi, et al., 1984). The second fragment contains amino acids 1 to 223 of the IBV matrix gene. The coding region was obtained from a cDNA clone of the Arkansas strain of IBV. The third fragment is an approximately 754 base pair NdeI to SalI restriction sub-fragment of the PRV BamHI restriction fragment #7 (Lomniczi, et al., 1984). The fourth fragment is an approximately 1191 base pair PstI to AvaII restriction sub-fragment of the HCMV genomic XbaI E fragment (D. R. Thomsen, et al., 1981). The fifth fragment contains amino acids 4 to 1162 of the IBV spike gene. The coding region was obtained from a cDNA clone of the Arkansas strain of IBV. The last fragment is an approximately 784 base pair SmaI to SmaI restriction sub-fragment of the HSV-1 BamHI restriction fragment Q (McGeoch, et al., 1985).
HOMOLOGY VECTOR 603-57.F1. The plasmid 603-57.F1 was constructed for the purpose of inserting the IBDV VP2 gene into HVT. The IBDV VP2 gene was inserted as a cassette into homology vector 435-47.1 at the unique HindIII site. The VP2 gene is under the control of the HCMV immediate early promoter and is followed by the HSV-1 TK poly adenylation signal. The VP2 gene was inserted in the same transcriptional orientation as the US2 in the parental homology vector. The cassette may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources. The first fragment is an approximately 1191 base pair PstI to AvaII restriction sub-fragment of the HCMV genomic XbaI E fragment (D. R. Thomsen, et al., 1981). The second fragment is an approximately 1081 base pair BclI to BamHI restriction sub-fragment of the full length IBDV cDNA clone (see SEQ ID NO:1). Note that the BclI site was introduced into the cDNA clone directly upstream of the VP2 initiator methionine by converting the sequence CGCAGC to TGATCA. The first and second fragments are oriented such that AvaII and BclI sites are contiguous. The third fragment is an approximately 784 base pair SmaI to SmaI restriction sub-fragment of the HSV-1 BamHI restriction fragment Q (McGeoch, et al., 1985).
HOMOLOGY VECTOR 633-13.27. The plasmid 633-13.27 was constructed for the purpose of inserting the MDV gB, gA and gD genes and the NDV HN and F genes into HVT. The HN and F genes are under the control of the PRV gpX and HCMV immediate early promoters respectively. The HN and F genes are followed by the PRV gX poly and HSV-1 TK adenylation signals respectively. All five genes were inserted in the same transcriptional orientation as the US2 gene in the parental homology vector. The genes were inserted in the following order MDV gA, NDV HN, NDV F, MDV gD, and MDV gB.
HOMOLOGY VECTOR 634-29.16. The plasmid 634-29.16 was constructed for the purpose of inserting the ILT virus gB and gD genes into HVT. The lacZ marker gene followed by the ILT gB and gD genes inserted as a cassette into the homology vector 172-29.31 at the unique XhoI site. The cassette may be constructed utilizing standard recombinant DNA techniques (Maniatis et al, 1982 and Sambrook et al, 1989), by joining restriction fragments from the following sources. The first fragment is an approximately 4229 base pair SalI to SalI restriction fragment derived from the lacZ marker gene described above and shown in FIG. 7. The second fragment is an approximately 2060 base pair EcoRI to BclI restriction sub-fragment of the ILT KpnI genomic restriction fragment #8 (10.6 KB). The third fragment is an approximately 754 base pair NdeI to SalI restriction sub-fragment of the PRV BamHI restriction fragment #7 (Lomniczi et al., 1984). Note that the second and third fragments are oriented such that BclI and NdeI sites are contiguous. The fourth fragment is the 3.0 KB ILT virus genomic EcoRI fragment containing the gB gene. All three genes are in the same transcriptional orientation as the UL43 gene.
EXAMPLES
Example 1
S-HVT-001
S-HVT-001 is a herpesvirus of turkeys (HVT) that contains the E. coli .beta.-galactosidase gene inserted into the unique long region of the HVT genome. The restriction enzyme map of HVT has been published (T. Igarashi, et al., 1985). This information was used as a starting point to engineer the insertion of foreign genes into HVT. The BamHI restriction map of HVT is shown in FIG. 1A. From this data, several different regions of HVT DNA into which insertions of foreign genes could be made were targeted. The foreign gene chosen for insertion was the E. coli .beta.-galactosidase (lacZ) gene, which we have used in PRV. The promoter was the PRV gpX promoter. The lacZ gene was inserted into the unique long region of HVT, specifically into the XhoI site in the BamHI #16 (3329 bp) fragment, and was shown to be expressed in an HVT recombinant by the formation of blue plaques using the substrate Bluogal.TM. (Bethesda Research Labs). Similarly, the lacZ gene has been inserted into the SalI site in the repeat region contained within the BamHI #19 (900 bp) fragment.
These experiments show that HVT is amenable to the procedures described within this application for the insertion and expression of foreign genes in herpesviruses. In particular, two sites for insertion of foreign DNA have been identified (FIGS. 1B and 1C).
Example 2
S-HVT-003
S-HVT-003 is a herpesvirus of turkeys (HVT) that contains the E. coli .beta.-galactosidase (lacZ) gene and the infectious bursal disease virus (IBDV) strain S40747 large segment of RNA (as a cDNA copy) inserted into the unique long region of the HVT genome. This IBDV DNA contains one open reading frame that encodes three proteins (5'VP2-VP4-VP3 3'), two of which are antigens to provide protection against IBDV infections of chickens. Expression of the genes for both .beta.-galactosidase and the IBDV polyprotein are under the control of the pseudorabies virus (PRV) gpX gene promoter. S-HVT-003, deposited under ATCC Accession No. VR 2178, was made by homologous recombination.
The IBDV genes were cloned by the cDNA CLONING PROCEDURE. Clones representing the genome of IBDV were screened by SOUTHERN BLOTTING OF DNA procedure against blots containing authentic IBDV RNA. Positive clones were then characterized by restriction mapping to identify groups of clones. Two such clones were identified, that together were found to represent the entire coding region of the IBDV large segment of RNA (3.3 kb dsRNA). One cDNA clone (2-84) contained an approximately 2500 base pair fragment representing the first half of the IBDV gene. The second clone (2-40) contained an approximately 2000 base pair fragment representing the distal half of the IBDV gene. Plasmid 2-84/2-40, representing the entire IBDV gene, was constructed by joining clone 2-84 and 2-40 at a unique PvuII site present in the overlapping sequences. The IBDV genome can be obtained from plasmid 2-84/2-40 as an approximately 3400 base pair SmaI to HpaI fragment. Confirmation of the nature of the proteins encoded by the IBDV gene was obtained by expressing the clone (2-84/2-40) in E. coli and detecting VP3 antigen using antiserum made against purified IBDV capsid proteins on Western blots. Applicants' sequence of the large DNA segment that encodes the IBDV antigens is given seq ID # 1. This sequence shows one open reading frame that will henceforth be referred to as the IBDV gene. The sequence of an Australian IBDV strain has been published which bears close homology to applicants' sequence (Hudson et al, 1986). Comparison of the amino acid differences between the two viruses revealed 29 amino acid changes within the 1012 amino acid coding region. There were only 3 amino acid differences deduced for VP4 and only 8 in VP3. In contrast, VP2 contained 18 amino acid changes, 14 of which were clustered between amino acids 139 to 332.
For insertion into the genome of HVT, the coding region for the IBDV gene was cloned between the PRV gpx promoter and the HSV TK poly-A signal sequence, creating plasmid 191-23. To aid in the identification of HVT recombinants made by homologous recombination containing the IBDV gene the gpX promoted IBDV fragment from plasmid 191-23 was inserted behind (in tandem to) a lacZ gene controlled by a gpX promoter. The resultant plasmid, 191-47, contains the E. coli lacZ gene and the IBDV gene under the control of individual PRV gpX promoters. In constructing plasmid 191-47, various DNA fragments were joined by recombinant DNA techniques using either naturally occurring restriction sites or synthetic linker DNA. Details concerning the construction of these genes contained in plasmid 191-47 can be seen in FIG. 2. The first segment of DNA (segment 1, FIG. 2) contains the gpX promoter region including the residues encoding the first seven amino acids of the gpX gene, and was derived from a subclone of the PRV BamHI #10 fragment as an approximately 800 base pair SalI to BamHI fragment. The second segment of DNA (segment 2, FIG. 2) contains the E. coli .beta.-galactosidase coding region from amino acid 10 to amino acid 1024 and was derived from the plasmid pJF751 (obtained from Jim Hoch, Scripps Clinic and Research Foundation) as an approximately 3300 base pair BamHI to BalI fragment followed by an approximately 40 base pair Ava I to Sma I fragment. The third segment of DNA (segment 3, FIG. 2) contains the gpX poly A signal sequence and was derived from a subclone of the PRV BamHI #7 fragment as an approximately 700 base pair NdeI to StuI fragment. Segment three was joined to segment two by ligating the NdeI end which had been filled in according to the POLYMERASE FILL-IN REACTION, to the SmaI site. The fourth segment of DNA (segment 4 FIG. 2) contains the gpX promoter (TATA box and cap site) and was derived from a subclone of the PRV BamHI #10 fragment as an approximately 330 base pair NaeI to AluI fragment. Additionally, segment four contains approximately 36 base pairs of HSV TK 5' untranslated leader sequence as a PstI to BglII fragment in which the PstI site has been joined to the AluI site through the use of a synthetic DNA linker (McKnight and Kingbury, 1982). DNA segments four through six were inserted as a unit into the unique Kpn I site of segment three which is located 3' of the gpX poly A signal sequence. The fifth segment of DNA (segment 5, FIG. 2) contains the entire coding region of the IBDV large segment of RNA (cDNA clone) as an approximately 3400 base pair SmaI to HpaI fragment. The SmaI site of segment five was fused to the BglII site of segment four which had been filled in according to the POLYMERASE FILL IN REACTION Expression of the IBDV gene (5' VP2-VP4-VP3 3'), is under the control of the gpX promoter (segment 4), but utilizes its own natural start and stop codons. The sixth segment of DNA (segment 6, FIG. 2) contains the HSV TK poly-A signal sequence as an approximately 800 base pair SmaI fragment (obtained from Bernard Roizman, Univ. of Chicago). The HpaI site of segment five was fused to the SmaI site of segment six through the use of a synthetic DNA liner.
In summary, the construct used to create S-HVT-003 (plasmid 191-47) contains (5' to 3') the PRV promoter, the gpX TATA box, the gpX cap site, the first seven amino acids of gpX, the E. coli .beta.-galactosidase (lacZ) gene, the PRV poly-A signal sequence, the PRV gpX promoter, the gpX TATA box, the gpX cap site, a fusion within the gpX untranslated 5' leader to the IBDV gene, IBDV start codon, a fusion within the IBDV untranslated 3' end to HSV TK untranslated 3' end, and the TK poly-A signal sequence. The cassette containing these genes was engineered such that it was flanked by two EcoRI restriction endonuclease sites. As a result, an approximately 9100 base pair fragment containing both lacZ gene and the IBDV gene can be obtained by digestion with EcoRI. Henceforth, the 9161 base pair EcoRI fragment will be referred to as the IBDV/lacZ cassette. The following procedures were used to construct S-HVT-003 by homologous recombination. The IBDV/lacZ cassette was inserted into the unique XhoI site present within a subclone of the HVT BamHI #16 fragment. To achieve this, the XhoI site was first changed to an EcoRI site through the use of an EcoRI linker. This site had previously been shown to be nonessential in HVT by the insertion of lacZ (S-HVT-001). It was also shown that the flanking homology regions in BamHI #16 were efficient in homologous recombination. Shown in FIG. 3, the genomic location of the BamHI #16 fragment maps within the unique long region of HVT. The complete nucleotide sequence of the approximately 3329 base pair BamHI #16 fragment is presented as seq ID #3. HVT DNA was prepared by the PREPARATION OF HERPESVIRUS DNA procedure. Cotransfections of HVT DNA and plasmid DNA into primary chick embryo fibroblast (CEF) cells were done according to the DNA TRANSFECTION FOR GENERATING RECOMBINANT HERPESVIRUS. The recombinant virus resulting from the cotransfection stock was purified by three successive rounds of plaque purification using the BLUOGAL SCREEN FOR RECOMBINANT HERPESVIRUS procedure. When 100% of the plaques were blue, the DNA was analyzed for the presence of the IBDV gene by the SOUTHERN BLOTTING OF DNA procedure. Southern blots, probing EcoRI digested S-HVT-003 DNA with an IBDV specific nick translated probe (plasmid 2-84/2-40), confirmed the presence of the 9100 base pair EcoRI fragment. This result confirmed that S-HVT-003 contained both the lacZ gene and the IBDV gene incorporated into its genome. Additional Southern blots, using a probe specific for BamHI #16, confirmed that the homologous recombination occurred at the appropriate position in BamHI #16 and that no deletions were created. No differences in the growth of S-HVT-003 compared to wild type virus (S-HVT-000) were observed in vitro.
Expression of IBDV specific proteins from S-HVT-003 were assayed in vitro using the WESTERN BLOTTING PROCEDURE. Cellular lysates were prepared as described in PREPARATION OF HERPESVIRUS CELL LYSATES. Briefly, the proteins contained in the cellular lysates of S-HVT-003 were separated by polyacrylamide gel electrophoresis, transferred to nitrocellulose, and probed with either an antiserum made against denatured purified IBDV capsid proteins or antiserum made against a synthetic peptide corresponding to a predicted imuno dominant region of the IBDV 40 kd (VP2) capsid protein. The filters were washed and treated with .sup.125 I! protein A to detect the position of the bound antibodies. FIG. 4 shows the results obtained using the antiserum made against denatured purified IBDV capsid proteins, which have been shown by the applicants to react primarily with VP3 (32 kd protein). As seen, S-HVT-003 produces a protein which is immunologically indistinguishable from the authentic VP3 protein from intact IBDV virions. Moreover, the polyprotein appears to be processed correctly, producing a VP3 species that comigrates with the authentic VP3 protein. Recent evidence using an Australian IBDV stain indicates that VP4 is involved in the processing of the precursor polyprotein into mature VP2 and VP3 protein species (Jagadish, et al., 1988). FIG. 5 shows the results obtained using a rabbit antiserum raised against a synthetic peptide that is homologous to a 14 amino acid region of the IBDV VP2 (40 kd) capsid protein. As seen, S-HVT-003 produces a protein that is immunologically indistinguishable from the authentic viral VP2 protein. In addition, the VP2 protein produced from S-HVT-003 comigrates with the 40 kd species of VP2 isolated from intact IBDV virions. This species represents a major component of infectious (complete) viral particles.
In summary, analysis of the expression of IBDV specific proteins from S-HVT-003 has shown that the polyprotein is processed in CEF cell culture, producing proteins of the appropriate size that react to immunological reagents specific for either VP2 or VP3 proteins on Western blots.
The following set of experiments was carried out in chickens to analyze the in vivo expression of the IBDV genes contained within S-HVT-003 as determined by seroconversion data, serum neutralization results, and protection from IBDV challenge.
The first experiment was designed to show the seroconversion of chickens to IBDV upon being vaccinated with S-HVT-003. Eleven 11-week-old chickens, seronegative to HVT and IBDV were obtained from SPAFAS Inc. Six birds were vaccinated subcutaneously in the abdominal region with 0.5 ml of a cellular suspension of CEF cells containing S-HVT-003 (40,000 PFU/ml). Serum samples were obtained every seven days for eight weeks for all birds in this study. On day 28 (4th week), three of these birds received a boost of S-HVT-003, while the other three birds received 0.5 ml of an inactivated IBDV vaccine inoculated subcutaneously in the cervical region. Three additional birds were given only the inactivated vaccine on day 28. Two birds served as contact controls and received no vaccinations. On day 56, all birds were sacrificed and necropsied. Table 1 show the results of the serum neutralization assay against IBDV. No detectable SN activity was observed in the birds given only S-HVT-003. Additionally, only one of the three birds that were given only the inactivated vaccine demonstrated low but detectable SN activity. SN titers were also detected in one of the three birds that received the S-HVT-003 followed by the inactivated IBDV vaccine boost; these titers were at a much higher level than with the inactivated IBDV vaccine alone. These results suggest that S-HVT-003 is priming the chicken for a secondary response against IBDV. In vitro analysis of the serum samples by WESTERN BLOTTING confirmed the seroconversion of the chickens to IBDV upon vaccination with S-HVT-003 both prior to and after boosts administered on day 28.
In the second experiment, twenty five 1-day old SPF chicks were vaccinated with S-HVT-003 (20 with 0.2 ml subcutaneously and 5 by bilateral eyedrop). Twenty chicks were kept as controls. On days four and seven postinfection, five vaccinates and two control birds were bled, sacrificed and their spleens removed for virus isolation. Spleen cell suspensions were made by standard method, and .noteq.1.times.10.sup.6 cells in 3 ml of chick embryo fibroblast (CEF) growth media were inoculated directly onto secondary cells. Cultures were incubated for 6-7 days and then scored for cytopathic effects (CPE) as determined by observing cell morphology. The cultures were passed a second time, and again scored for CPE. The results are shown in Table 2. All nonvaccinated control birds remained negative for HVT for both day 4 and 7 spleen cell isolations. Four out of the five birds vaccinated with S-HVT-003 were positive for HVT at day 4 for both the first and second passages. One bird did not produce virus, this may represent a vaccination failure. Five out of five birds were positive for HVT on day 7 at both passage one and two. Overall, the vector recovery experiment demonstrates that S-HVT-003 replicates as well as wild type HVT virus in vivo and that insertion of the IBDV/lacZ cassette into the XhoI site of BamHI #16 does not result in detectable attenuation of virus. Subsequent experiments examining the recovered virus by the BLUOGAL SCREEN FOR RECOMBINANT HERPESVIRUS procedure confirmed the in vivo stability of S-HVT-003, by demonstrating .beta.-galactosidase expression in 100% of the viruses.
At days 0, 4, 7, 14, 21, and 27 postinfection, blood samples were obtained from the rest of the chickens for determining serum ELISA titers against IBDV and HVT antigens as well as for virus neutralizing tests against IBDV. Additionally, at 21 days postinfection five control and fourteen vaccinated chicks were challenged with virulent IBDV by bi-lateral eyedrop (10.sup.3.8 EID.sub.50). All birds were sacrificed 6-days post challenge and bursa to body weight ratios were calculated. A summary of the results is shown in tables X and XI, respectively. As presented in Table 3, no antibodies were detected against HVT antigens by ELISA prior to 21-27 days post vaccination. In chickens, the immune response during the first two weeks post hatch is both immature and parentally suppressed, and therefore these results are not totally unexpected. In contrast, IBDV ELISA's were negative up to day 21 postvaccination, and were only detectable after challenge on day 27. The ELISA levels seen on day 27 postvaccination indicate a primary response to IBDV. Table 3I comparing the Bursa-to-Body weight ratios for challenged controls and vaccinated/challenged groups show no significant differences. Vaccination with S-HVT-003 under these conditions did not prevent infection of the vaccinated birds by IBDV challenge, as indicated by the death of four vaccinated birds following challenge.
A third experiment was conducted repeating Experiment 2 but using immunologically responsive chicks (3 weeks of age). Six three week old SPF leghorn chickens were vaccinated intraperitoneally with 0.2 ml of S-HVT-003 (one drop in each eye). Serum samples were obtained every seven days for six-weeks and the birds were challenged with the virulent USDA standard challenge IBDV virus on day 43 postvaccination. Six days post challenge, the control, vaccinated-challenged, and challenged groups were sacrificed and bursas were harvested for probing with anti-IBDV monoclonal antibodies (MAB) (provided by Dr. David Snyder, Virginia-Maryland Regional College of Veterinary Medicine). Bursal homogenates were prepared by mixing 1 ml of 0.5% NP40 with one bursa. Bursa were then ground and briefly sonicated. Supernatants from the homogenates were reacted with the R63 MAB which had been affixed to 96-well Elisa plates via a protein A linkage. After incubation, a biotin labeled preparation of the R63 MAB was added. After washing, an avidin-horse radish peroxidase conjugate was added and incubated. Tests were developed with Tris-malcate buffer (TMB)+H.sub.2 O.sub.2 substrate. The test results are presented in Table 5. The data show the presence of high levels of IBDV antigen in all bursa in the vaccinate-challenged group and in the challenged group. No IBDV antigen was detected in the controls. IBDV specific antigen could be detected at dilutions of over 1/1000, and there does not appear to be differences between vaccinated and non-vaccinated challenged groups. HVT titers as determined by ELISA were first detectable at day 7 in four out of the six birds vaccinated. By day 14, six out of six vaccinated birds showed titers to HVT. All six birds continued to show HVT titers throughout the experiment. No IBDV SN titers were seen prior to the challenge. In contrast, analysis of these same serum samples by the WESTERN BLOTTING procedure demonstrated the seroconversion of chickens vaccinated with S-HVT-003 to IBDV prior to administration of the virus challenge. The level of response, however, remains small unless boosted by challenge. Comparison between the vaccinated/challenged and challenged only groups clearly demonstrates that the level of reactivity by Western blots is much higher in the vaccinated/challenged group. These results show that S-HVT-003 is seroconverting vaccinated birds to IBDV, and suggest that the level of IBDV specific expression are not high enough to induce a neutralizing response in the birds.
S-HVT-003 shows the merit of the vaccine approach the applicants have invented. HVT has been engineered to simultaneously express the foreign antigens (.beta.-galactosidase and IBDV antigens) that are recognized in the host by an immune response directed to these proteins. Applicants' invention will enable progression towards a product based on this technology.
Example 3
S-HVT-004
S-HVT-004 is a recombinant herpesvirus of turkeys that contains the Marek's disease virus (MDV) glycoprotein A (gpA) gene inserted into the long unique region, and the .beta.-galactosidase (lacZ) gene also inserted in the long unique region. The MDV antigen is more likely to elicit the proper antigentic response than the HVT equivalent antigen.
The MDV gpA gene was cloned by standard DNA cloning gpA procedures. An EcoRI restriction fragment had been reported to contain the MDV gpA gene (Isfort et al., 1984) and this fragment was identified by size in the DNA clones. The region of the DNA reported to contain the gpA gene was sequenced by applicants and found to contain a glycoprotein gene as expected. The DNA from this gene was used to find the corresponding gene in HVT by the SOUTHERN BLOTTING OF DNA procedure, and a gene in HVT was identified that contained a very similar sequence. This gene is the same gene previously called gpA (Isfort et al., 1984).
For insertion into the genome of HVT, the MDV gpA gene was used intact because it would have good herpesvirus signal sequences already. The lacZ gene was inserted into the XhoI fragment in BamHI fragment #16, and the MDV gpA gene was inserted behind lacZ as shown in FIGS. 6A and 6B. Flanking regions in BamHI #16 were used for the homologous recombination. HVT DNA and plasmid DNA were co-transfected according to the DNA TRANSFECTION FOR GENERATING RECOMBINANT HERPESVIRUS procedure into primary chick embryo fibroblast (CEF) cells. The virus from the transfection stock was purified by successive plaque purifications using the BLUOGAL SCREEN FOR RECOMBINANT HERPESVIRUS procedure. At the end of this procedure, when 100% of the plaques were blue, the DNA was analyzed for the presence of the MDV gpA gene. S-HVT-004 is a recombinant virus that contains both the .beta.-galactosidase gene and the MDV gpA gene incorporated into the genome.
FIG. 6C shows the structure of S-HVT-004.
Example 4
Newcastle Disease Virus
Newcastle disease virus (NDV) is closely related to PI-3 in overall structure. We have engineered the hemagglutinin (HN) and fusion (F) genes of PI-3 for expression in IBR (ref). Similarly we have cloned the hemagglutinin (HN) and fusion (F) genes from NDV for use in the herpesvirus delivery system (Herpesvirus of turkeys, HVT).
The procedures that we have utilized for construction of herpesvirus control sequences for expression have been applied to NDV.
Infectious Bronchitis Virus
Infectious bronchitis virus (IBV) is a virus of chickens closely related in overall structure to TGE. We have engineered the major neutralizing antigen of TGE for expression in PRV (ref). Similarly we have cloned the major neutralizing antigens from three strains of IBV: Massachusetts (SEQ ID NO: 14), Connecticut (SEQ ID NO: 16), and Arkansas-99 (SEQ ID NO: 18) for use in a herpesvirus delivery system (HVT).
The procedures that we have utilized for the construction of herpesvirus control sequences for expression have been applied to IBV.
Example 5
S-HVT-045
S-HVT-045 is a recombinant herpesvirus of turkeys that contains the Marek's disease virus (MDV) glycoprotein B (gpB) gene inserted into the short unique region. The MDV antigen is more likely to elicit the proper antigenic response than the HVT equivalent antigen. S-HVT-045 has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganisms for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A.
The MDV gpB gene was cloned by standard DNA cloning procedures. The MDV gpB gene was localized to a 3.9 kb EcoRI-SalI fragment using an oligonucleotide probe based on the HSV gB sequence in a region found to be conserved among known herpesvirus gB genes. The restriction map 3.9 kb EcoRI-SalI fragment is similar to the published map (Ross et al., 1989).
For insertion into the HVT genome, the MDV gpB was used intact because it would have good herpesvirus signal sequences already. The MDV gpB gene was inserted into a cloned 17.15 kb BamHI-EcoRI fragment derived from the HVT BamHI #1 fragment. The site used for insertion was the StuI site within HVT US2, previously utilized for the construction of S-HVT-012. The site was initially altered by insertion of a unique HindIII linker, and the MDV gpB gene was inserted by standard DNA cloning procedures. Flanking regions in the 17.15 kb BamHI-EcoRI fragment were used, together with the remaining cloned HVT fragments using the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUSES FROM OVERLAPPING SUBGENOMIC FRAGMENTS. The virus obtained from the transfection stock was plaque purified and the DNA was analyzed for the presence of the MDV gpB gene. S-HVT-045 is a recombinant virus that contains the MDV gpB gene incorporated into the genome at the StuI site in HVT US2 gene.
Testing of Recombinant S-HVT-045
Two studies were conducted to demonstrate the effectiveness of these recombinant HVT/MDV viruses in protecting against challenge with virulent Marek's disease virus. In Study A, one-day-old specific pathogen free (SPF) chicks were vaccinated with either S-HVT-045 or S-HVT-046. Seven days post-vaccination, vaccinated chicks, and non-vaccinated, control chicks were challenged with the highly virulent MD-5 strain of Marek's disease virus. Following a 6-week post-challenge observation period for clinical signs typical of Marek's disease, all chicks were necropsied and examined for lesions diagnostic of Marek's disease. The results, in Table 6, show that both recombinant viruses gave complete protection against a challenge that caused Marek's disease in 90% of non-vaccinated control chicks.
In a second study, one-day-old chicks were vaccinated either with S-HVT-045 or S-HVT-047. A third group of chicks were vaccinated with a USDA-licensed, conventional vaccine comprised of HVT and SB-1 viruses. Five days post-vaccination, the vaccinated chicks and a group of non-vaccinated, control chicks were challenged with virulent Marek's virus, strain RBLB. The chicks were observed for 8 weeks for clinical signs of Marek's disease, then necropsied and observed for Marek's lesions. This study demonstrated the ability of HVT-045 and HVT-047 to provide 100% protection against challenge (Table 1). The commercial vaccine gave 96% protection, and 79% of the non-vaccinated chicks developed Marek's disease.
Example 6
S-HVT-012
S-HVT-012 is a recombinant herpesvirus of turkeys that contains the E. coli .beta.-galactosidase (lacZ) gene inserted into the short unique region. The lacZ gene was used to determine the viability of this insertion site in HVT ATCC F-126 ("Calnek")!. S-HVT-012 has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganisms for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A.
For insertion into the genome of HVT, the .beta.-galactosidase gene was introduced into the unique StuI site of the cloned EcoRI fragment #7 of HVT, i.e., the fragment containing the StuI site within the US2 gene of HVT (as described in Methods and Materials). Flanking regions of EcoRI fragment #7 were used for homologous recombination. HVT DNA and plasmid DNA were co-transfected according to the DNA TRANSFECTION FOR GENERATING RECOMBINANT VIRUS procedure into primary chick embryo fibroblast (CEF) cells. A blue virus obtained from the transfection stock was purified by successive plaque purifications using the BLUOGAL SCREEN FOR RECOMBINANT HERPESVIRUS procedure. At the end of this procedure, when 100% of the plaques were blue, the DNA was analyzed for the presence of the lacZ gene. S-HVT-012 is a recombinant virus that contains the lacZ gene incorporated into the genome at the StuI site within the US2 gene of HVT.
Testing of Recombinant S-HVT-012
S-HVT-012 may be formulated as a vaccine in the same manner as S-HVT-045. When administered to chickens, such a vaccine provides protection against Marek's disease virus.
Example 7
Sites for Insertion of Foreign DNA into HVT
In order to define appropriate insertion sites, a library of HVT BamHI and EcoRI restriction fragments was generated. Several of these restriction fragments (BamHI fragments #16 and #13, and EcoRI fragments #6, #7, and #9 (see FIG. 1)) were subjected to restriction mapping analysis. One unique restriction site was identified in each fragment as a potential insertion site. These sites included XhoI in BamHI fragments #13 and #16, and EcoRI fragment #9 and SalI in EcoRI fragment #6 and StuI in EcoRI fragment #7. A .beta.-galactosidase (lacZ) marker gene was inserted in each of the potential sites. A plasmid containing such a foreign DNA insert may be used according to the DNA COTRANSFECTION FOR GENERATING RECOMBINANT HERPESVIRUSES to CONSTRUCT a HVT containing the foreign DNA. For this procedure to be successful it is important that the insertion site be in a region non-essential to the replication of the HVT and that the site be flanked with HVT DNA appropriate for mediating homologous recombination between virus and plasmid DNAs. The plasmids containing the lacZ marker gene were utilized in the DNA COTRANSFECTION FOR GENERATING RECOMBINANT HERPESVIRUSES. The generation of recombinant virus was determined by the BLUOGAL SCREEN FOR RECOMBINANT HERPESVIRUS. Three of the five sites were successfully used to generate a recombinant virus. In each case the resulting virus was easily purified to 100%, clearly defining an appropriate site for the insertion of foreign DNA. The three homology vectors used to define these sites are described below.
Example 7A
Homology Vector 172-29.31
The homology vector 172-29.31 contains the HVT BamHI #16 fragment and is useful for the insertion of foreign DNA into HVT. Plasmid 172-29.31 contains a unique XhoI restriction site into which foreign DNA may be cloned. We have demonstrated that the XhoI site in homology vector 172-29.31 may be used to insert foreign DNA into HVT by the construction of at least three recombinant HVT (see examples 1-3).
The homology vector 172-29.31 was further characterized by DNA sequence analysis. The complete sequences of the BamHI #16 fragment was determined. Approximately 2092 base pairs of the adjacent BamHI #13 fragment was also determined (see SEQ ID 3). This sequence indicates that the open reading frame coding for HVT glycoprotein A (gA) spans the BamHI #16--BamHI #13 junction. The HVT gA gene is homologous to the HSV-1 glycoprotein C (gC). The XhoI site interrupts an ORF which lies directly upstream of the HVT gA gene. This ORF shows amino acid sequence homology to the PRV p43 and the VZV gene 15. The PRV and VZV genes are the homologues of HSV-1 UL43. Therefore we have designated this ORF as HVT UL43. It should be noted that the HVT UL43 does not exhibit direct homology to HSV-1 UL43. Although HVT UL43 is located upstream of the HVT gC homologue it is encoded on the same DNA strand as HVT gA, where as the HSV-1 UL43 is on the opposite strand relative to HSV-1 gC. The XhoI site interrupts UL43 at approximately amino acid 6, suggesting that the UL43 gene is non-essential for HVT replication.
Example 7B
Homology Vector 435-47.R17
The homology vector 435-47.R17 contains the HVT EcoRI #7 fragment and is useful for the insertion of foreign DNA into HVT. Plasmid 435-47.R17 contains a unique HindIII restriction site into which foreign DNA may be cloned. The HindIII restriction site in plasmid results from the insertion of a HindIII linker into the naturally occurring StuI site of EcoRI fragment #7. We have demonstrated that the HindIII site in homology vector 435-47.R17 may be used to insert foreign DNA into HVT by the construction of at least 25 recombinant HVT.
DNA sequence analysis at the StuI indicated that this fragment contains open reading frames coding for US10, US2, and US3. The StuI site interrupts US2 at approximately amino acid 124, suggesting that the US2 gene is non-essential for HVT replication.
Example 7C
Homology Vector 172-63.1
The homology vector 172-63.1 contains the HVT EcoRI #9 fragment and is useful for the insertion of foreign DNA into HVT. Plasmid 172-63.1 contains a unique XhoI restriction site into which foreign DNA may be cloned. We have demonstrated that the XhoI site in homology vector 172-63.1 may be used to insert foreign DNA into HVT by the construction of S-HVT-014 (see example 8).
Example 8
S-HVT-014
S-HVT-014 is a recombinant herpesvirus of turkeys that contains the E. coli .beta.-galactosidase (lacZ) gene inserted into the long unique region. The lacZ gene was used to determine the viability of this insertion site in HVT ATCC F-126 ("Calnek")!.
For insertion into the genome of HVT, the .beta.-galactosidase gene was introduced into the unique XhoI site of the cloned EcoRI fragment #9 (as described in Methods and Materials). Flanking regions of EcoRI fragment #8 were used for homologous recombination. HVT DNA and plasmid DNA were co-transfected according to the DNA TRANSFECTION FOR GENERATING RECOMBINANT VIRUS procedure into primary chick embryo fibroblast (CEF) cells. A blue virus obtained from the transfection stock was purified by successive plaque purifications using the BLUOGAL SCREEN FOR RECOMBINANT HERPESVIRUS procedure. At the end of this procedure when 100% of the plaques were blue. S-HVT-014 is a recombinant virus that contains the lacZ gene incorporated into the genome at the XhoI site within the EcoRI #9 fragment of HVT.
Testing of Recombinant S-HVT-014
S-HVT-014 may be formulated as a vaccine in the same manner as S-HVT-045. When administered to chickens, such a vaccine provides protection against Marek's disease virus.
Example 9
S-HVT-005
S-HVT-005 is a recombinant herpesvirus of turkeys that contains the E. coli .beta.-galactosidase (lacZ) gene inserted into the long unique region. The lacZ gene was used to determine the viability of this insertion site in HVT ATCC F-126 ("Calnek")!.
For insertion into the genome of HVT, the .beta.-galactosidase gene was introduced into an approximately 1300 base pair deletion of the XhoI #9 fragment of HVT. The deletion which lies between the unique MluI and EcoRV sites removes the complete coding region of the HVT gA gene (see SEQ ID 3). Flanking regions of XhoI fragment #9 were used for homologous recombination. HVT DNA and plasmid DNA were co-transfected according to the DNA TRANSFECTION FOR GENERATING RECOMBINANT VIRUS procedure into primary chick embryo fibroblast (CEF) cells. A blue virus obtained from the transfection stock was purified by successive plaque purifications using the BLUOGAL SCREEN FOR RECOMBINANT HERPESVIRUS procedure. At the end of this procedure, when 100% of the plaques were blue, the DNA was analyzed for the presence of the lacZ gene. S-HVT-005 is a recombinant virus that contains the lacZ gene incorporated into the genome at in place of the deleted gA gene of HVT.
Testing of Recombinant S-HVT-005
S-HVT-005 may be formulated as a vaccine in the same manner as S-HVT-045. When administered to chickens, such a vaccine provides protection against Marek's disease virus.
Example 10
Marek's Disease Vaccines
Recombinant HVT expressing glycoproteins from MDV make superior vaccines for Marek's Disease. We have constructed several recombinant HVT expressing MDV glycoproteins S-HVT-004 (example 3), S-HVT-005 (example 9), S-HVT-045 (example 5), S-HVT-046 (example 10A), S-HVT-047 (example 10B), S-HVT-062 (example 10C).
Example 10A
S-HVT-046
S-HVT-046 is a recombinant herpesvirus of turkeys that contains the Marek's disease virus (MDV) glycoprotein B (gB) and glycoprotein A (gA) genes inserted into the short unique region. The MDV genes are inserted in the same transcriptional orientation as the US2 gene. The MDV antigens are more likely to elicit the proper antigenic response than the HVT equivalent antigen.
S-HVT-046 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 437-26.26 with BamHI and HindIII, and 456-17.22 uncut. Insertion of the appropriate DNA was confirmed by southern blot analysis.
Example 10B
S-HVT-047
S-HVT-047 is a recombinant herpesvirus of turkeys that contains the MDV gB and gA genes inserted into the short unique region. The MDV genes are inserted in the opposite transcriptional orientation as the US2 gene. The MDV antigens are more likely to elicit the proper antigenic response than the HVT equivalent antigen.
S-HVT-047 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 437-26.26 with BamHI and HindIII, and 456-17.18 uncut. Insertion of the appropriate DNA was confirmed by southern blot analysis.
Example 10C
S-HVT-062
S-HVT-062 is a recombinant herpesvirus of turkeys that contains the MDV gB, glycoprotein D (gD) and gA genes inserted into the short unique region. The MDV genes are inserted in the same transcriptional orientation as the US2 gene. The MDV antigens are more likely to elicit the proper antigenic response than the HVT equivalent antigen. S-HVT-062 has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganisms for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A. under ATCC Accession No. VR 2401 on Feb. 23, 1993.
S-HVT-062 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 566-41.5, with BamHI and HindIII, and 456-17.22 uncut. Insertion of the appropriate DNA was confirmed by southern blot analysis.
Testing of Recombinant HVT Expressing MDV Antigens
Two studies were conducted to demonstrate the effectiveness of these recombinant HVT/MDV viruses in protecting against challenge with virulent Marek's disease virus. In Study 1, one-day-old specific pathogen free (SPF) chicks were vaccinated with either S-HVT-045, S-HVT-046, or S-HVT-047. Five days post-vaccination, vaccinated chicks, and non-vaccinated, control chicks were challenged with MDV. Following a 6-week post-challenge observation period for clinical signs typical of Marek's disease, all chicks were necropsied and examined for lesions diagnostic of Marek's disease. The results, in Table 7, show these recombinant viruses gave complete protection against a challenge that caused Marek's disease in 84% of non-vaccinated control chicks.
In the second study, one-day-old chicks were vaccinated with S-HVT-062. Two more groups of chicks were vaccinated with a USDA-licensed, conventional vaccines comprised of HVT and a combination HVT and SB-1 viruses. Five days post-vaccination, the vaccinated chicks and a group of non-vaccinated, control chicks were challenged with MDV. The chicks were observed for 8 weeks for clinical signs of Marek's disease, then necropsied and observed for Marek's lesions. This study demonstrated the ability of S-HVT-062 to provide 100% protection against challenge (Table 7). The commercial vaccines gave 81% and 95% protection, respectively and 100% of the non-vaccinated chicks developed Marek's disease.
Example 11
Bivalent Vaccines Against Newcastle Disease and Marek's Disease
Recombinant HVT expressing proteins from NDV make bivalent vaccines protecting against both Marek's Disease and Newcastle disease. We have constructed several recombinant HVT expressing NDV proteins S-HVT-007 (example 11A), S-HVT-048 (example 11B), S-HVT-049 (example 1C), S-HVT-050 (example 1D), and S-HVT-106 (example 11E).
Example 11A
S-HVT-007
S-HVT-007 is a recombinant herpesvirus of turkeys that contains a hybrid E. coli lacZ NDV HN hybrid protein gene under the control of the PRV gX promoter and the NDV F gene under the control of the HSV-1 a 4 promoter inserted into the long unique region. The NDV genes are inserted in the same transcriptional orientation as the UL43 gene.
To construct S-HVT-007 HVT DNA and the plasmid 255-18.B16 were co-transfected according to the DNA TRANSFECTION FOR GENERATING RECOMBINANT VIRUS procedure into primary chick embryo fibroblast (CEF) cells. A blue virus obtained from the transfection stock was purified by successive plaque purifications using the BLUOGAL SCREEN FOR RECOMBINANT HERPESVIRUS procedure. At the end of this procedure, when 100% of the plaques were blue.
Example 11B
S-HVT-048
S-HVT-048 is a recombinant herpesvirus of turkeys that contains the MDV gB and gA genes and the NDV F gene under the control of the HCMV immediate early promoter inserted into the short unique region. The MDV and NDV genes are inserted in the same transcriptional orientation as the US2 gene.
S-HVT-048 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 437-26.26 with BamHI and HindIII, and 535-70.3 uncut. Insertion of the appropriate DNA was confirmed by southern blot analysis.
Example 11C
S-HVT-049
S-HVT-049 is a recombinant herpesvirus of turkeys that contains the MDV gB and gA genes and the NDV HN gene under the control of the PRV gX promoter inserted into the short unique region. The MDV and NDV genes are inserted in the same transcriptic entation as the US2 gene.
S-HVT-049 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 437-26.26 with BamHI and HindIII, and 549-62.10 uncut. Insertion of the appropriate DNA was confirmed by southern blot analysis.
Example 11D
S-HVT-050
S-HVT-050 is a recombinant herpesvirus of turkeys that contains the MDV gB and gA genes and the NDV HN and F genes. The NDV genes are under the control of the PRV gX and HCMV immediately promoters respectively. All four genes are inserted into the short unique region in the same transcriptional orientation as the US2 gene.
S-HVT-050 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 437-26.26 with BamHI and HindIII, and 549-24.15 uncut. Insertion of the appropriate DNA was confirmed by southern blot analysis. S-HVT-050 has been deposited pursuant to the Budapest Treaty on the International Deposit of Microorganisms for the Purposes of Patent Procedure with the Patent Culture Depository of the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 U.S.A.
Example 11E
S-HVT-106
S-HVT-106 is a recombinant herpesvirus of turkeys that contains the MDV gA, gB, gD genes and the NDV HN and F genes. The NDV genes are under the control of the PRV gX and HCMV immediately promoters respectively. All five genes are inserted into the short unique region in the same transcriptional orientation as the US2 gene.
S-HVT-050 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 437-26.26 with BamHI and HindIII, and 633-13.27 uncut.
Testing of Recombinant HVT Expressing NDV Antigens
Two studies were conducted to demonstrate the effectiveness of these recombinant HVT/MDV/NDV viruses in protecting against challenge with virulent Newcastle and Marek's disease viruses. In Study 1, one-day-old specific pathogen free (SPF) chicks were vaccinated with either S-HVT-048, S-HVT-049, S-HVT-050, or a USDA-licensed, conventional vaccine comprised of NDV B1/B1 virus. Three weeks post-vaccination, vaccinated chicks, and non-vaccinated, control chicks were challenged with NDV. Birds were then observed for clinical signs of disease. The results, in Table 8, show these recombinant viruses (S-HVT-048 and S-HVT-050) gave complete against a challenge that caused Newcastle disease in 100% of non-vaccinated control chicks. Recombinant virus S-HVT-049 gave partial protection against Newcastle disease.
In the second study, one-day-old chicks were vaccinated with S-HVT-050. Two more groups of chicks were vaccinated with a USDA-licensed, conventional vaccines comprised of HVT and a combination HVT and SB-1 viruses. Five days post-vaccination, the vaccinated chicks and a group of non-vaccinated, control chicks were challenged with MDV. The chicks were observed for 8 weeks for clinical signs of Marek's disease, then necropsied and observed for Marek's lesions. This study demonstrated the ability of S-HVT-050 to provide protection greater than the commercial Marek's disease vaccines.
Example 12
Bivalent Vaccines Against Infectious Laryngotracheitis and Marek's Disease
Recombinant HVT expressing glycoproteins from ILT virus make bivalent vaccines protecting against both Marek's disease and infectious laryngotracheitis. We have constructed several recombinant HVT expressing ILT virus glycoproteins S-HVT-051 (example 12A), S-HVT-052 (example 12B), and S-HVT-104 (example 11C).
Example 12A
S-HVT-051
S-HVT-051 is a recombinant herpesvirus of turkeys that contains the ILT virus gB gene inserted into the short unique region. The ILT gene is inserted in the same transcriptional orientation as the US2 gene.
S-HVT-051 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 437-26.26 with BamHI and HindIII, and 528-11.34 uncut. Insertion of the appropriate DNA was confirmed by southern blot analysis.
Example 12B
S-HVT-052
S-HVT-052 is a recombinant herpesvirus of turkeys that contains the ILT virus gD gene inserted into the short unique region. The ILT gene is inserted in the opposite transcriptional orientation as the US2 gene.
S-HVT-052 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 437-26.26 with BamHI and HindIII, and 528-03.37 uncut. Insertion of the appropriate DNA was confirmed by southern blot analysis.
Example 12C
S-HVT-104
S-HVT-104 is a recombinant herpesvirus of turkeys that contains six foreign genes. The MDV gA, gB, and gD genes are inserted in the unique short region in the same transcriptional orientation as the US2 gene. An E. coli lacZ marker gene and the ILT gB and gD genes are inserted in BamHI #16 region in the same transcriptional orientation as the UL43 gene.
To construct S-HVT-104 DNA from S-HVT-062 and the plasmid 634-29.16 were co-transfected according to the DNA TRANSFECTION FOR GENERATING RECOMBINANT VIRUS procedure into primary chick embryo fibroblast (CEF) cells.
Testing of Recombinant HVT Expressing ILT Antigens
The following study was conducted to demonstrate the effectiveness of these recombinant HVT/ILT viruses in protecting against challenge with virulent Infectious Laryngotracheitis virus. One-day-old specific pathogen free (SPF) chicks were vaccinated with either S-HVT-051, S-HVT-052, a combination of S-HVT-051 and S-HVT-052, or a USDA-licensed, conventional vaccine comprised of ILT virus. Two to three weeks post-vaccination, vaccinated chicks, and non-vaccinated, control chicks were challenged with ILT: Birds were then observed for clinical signs of disease. The results, in Table 9, show these recombinant viruses (S-HVT-051 and S-HVT-052) gave protection against challenge with ILT virus comparable to a commercial ILT vaccine.
Animals vaccinated with the vaccines described here may be easily differentiated from animals infected with virulent ILT. This is accomplished by testing the suspect birds for antibodies to any ILT antigens other than gB or gD. Examples of such antigens are ILT glycoproteins C, E, and G. Vaccinated, uninfected birds will be negative for these antigens whereas infected birds will be positive.
Example 13
Bivalent Vaccines Against Infectious Bursal Disease and Marek's Disease
Recombinant HVT expressing proteins from IBDV make bivalent vaccines protecting against both Marek's Disease and infectious bursal disease. We have constructed several recombinant HVT expressing IBDV proteins these viruses include S-HVT-003 (example 2) and S-HVT-096.
S-HVT-096 is a recombinant herpesvirus of turkeys that contains the IBDV VP2 gene, under the control of the HCMV immediate early promoter, inserted into the short unique region. The IBDV gene is inserted in the same transcriptional orientation as the US2 gene.
S-HVT-096 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 556-60.6 with BamHI, and 602-57.F1 uncut. Insertion of the appropriate DNA was confirmed by southern blot analysis.
Testing of Recombinant HVT Expressing IBDV Antigens
S-HVT-096 was assayed for expression of VP2 by black plaque and western blot analysis. Both assays indicated that the virus was expressing high levels of protein which reacts specifically with an IBDV neutralizing monoclonal antibody. This virus will be useful as a vaccine against infectious bursal disease.
Example 14
Bivalent Vaccines Against Infectious Bronchitis and Marek's Disease
S-HVT-066 is a recombinant herpesvirus of turkeys that contains the MDV gB, gD and gA genes and the IBV spike and matrix genes. The IBV spike and matrix genes are under the control of the HCMV immediate early and PRV gX promoters respectively. All five genes are inserted into the short unique region. The MDV and IBV genes are inserted in the same transcriptional orientation as the US2 gene.
S-HVT-066 was constructed according to the PROCEDURE FOR GENERATING RECOMBINANT HERPESVIRUS FROM SUBGENOMIC DNA FRAGMENTS. The following combination of subgenomic clones and enzymes were used: 407-32.2C3 with NotI, 172-07.BA2 with BamHI, 407-32.5G6 with NotI, 407-32.1C1 with NotI, 437-26.24 with BamHI and HindIII, 556-60.6 with BamHI, and 567-72.1D uncut. Insertion of the appropriate DNA was confirmed by southern blot analysis.
Testing of Recombinant HVT Expressing IBV Antigens
S-HVT-066 was assayed for expression of the IBV spike protein by black plaque and western blot analysis. Both assays indicated that the virus was expressing high levels of protein which reacts specifically with an IBV neutralizing monoclonal antibody. This virus will be useful as a vaccine against infectious bronchitis.
Example 21
Vaccines utilizing HVT to express antigens from various pathogens
We also anticipate that antigens from the following pathogens may also be utilized to develop poultry vaccines: Chick anemia agent, Avian encephalomyelitis virus, Avian reovirus, Avian paramyxoviruses, Avian influenza virus, Avian adenovirus, Fowl pox virus, Avian coronavirus, Avian rotavirus, Salmonella spp E. coli, Pasteurella spp, Haemophilus spp, Chlamydia sppI Mycoplasma sppI Campylobacter spp, Bordetella spp, Poultry nematodes, cestodes, trematodes, Poultry mites/lice, Poultry protozoa (Eimeria spp, Histomonas spp, Trichomonas spp).
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Claims
What is claimed:
1. A recombinant herpesvirus of turkeys designated S-HVT-062 (ATCC Accession No. VR 2401).
2. A vaccine which comprises an effective immunizing amount of the recombinant herpesvirus of turkeys of claim 1 and a suitable carrier.
3. The vaccine of claim 2, wherein the suitable carrier is a physiologically balanced culture medium containing stabilizing agents.
4. The vaccine of claim 2, wherein the effective immunizing amount is from about 10.sup.2 to about 10.sup.9 PFU/dose.
5. A method of immunizing a fowl against Marek's disease virus which comprises administering to the fowl an effective immunizing dose of the vaccine of claim 2.
6. The method of claim 5, wherein the vaccine is administered by intramuscular, subcutaneous, intraperitoneal, or intravenous injection.
7. The method of claim 5, wherein the vaccine is administered intranasally, intraocularly, or orally.
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- Fukuchi, K., et al. (1985) "The Structure of Marek disease virus DNA: The presence of unique expansion in nonpathogenic viral DNA", Proc.Natl.Acad.Sci.USA vol. 82, pp. 751-754 (Exhibit 19).
- Koomey, Michael J., et al. (1984) "Deletion of DNA Sequences in a Nononcogenic Variant of Herpesvirus saimiri", J.Virol. pp. 662-665, vol.50 No. 2 (Exhibit 20).
- Spaete, Richard R. and Mocarski, Edward S., (1987) "Insertion and deletion mutagenesis of the human cytomegalovirus genome", Proc.Natl.Acad.Sci.USA vol.84, pp. 7213-7217 (Exhibit 21).
- Shih, Richard R. And Mocarski, Edward S., (1987) "Insertion and deletion mutagenesis of the human cytomegalovirus genome", Proc. Natl. Acad. Sci. USA vol. 84, pp. 7213-7217 (Exhibit 22).
- Edwards, Stirling J., (1988) "Expression of hepatitis B virus S gene by herpes simplex virus type 1 vectors carrying .alpha.-and .beta.-regulates gene chimeras", Proc. Natl. Acad. Sci. USA vol. 81, pp. 5867-5870 (Exhibit 23).
- Roizman, Bernard, (1983) "Bioengineering of herpes simplex virus variants for potential use as live vaccines", Cold Spring Harbor Conference on New Approaches to Virla Vaccines, pp. 275-281 (Exhibit 24).
- Moss, Bernard, (1991) "Vaccinia Virus: A Tool for Research and Vaccine Development", Science 252:1662-1667 (Exhibit 25).
- Weir, Jerry P., and Narayanan, P.R., (1988) "The use of .beta.-galactosidase as a marker gene to define the regulatory sequences of the herpes simplex virus type 1 glycoprotein C gene in recombinant herpesviruses", Nucleic Acids Research 16:10627-10282 (Exhibit 26).
- Meignier, Bernard, (1991) "Genetically Engineered Attenuated Herpes Simplex Viruses Viruses", Reviews of Infectious Diseases 13(Suppl II):S895-S897 (Exhibit 27).
- Zuckermann, F.A. et al., (1989) "Role of Pseudorabies Virus Glycoproteins in Immune Response", Vaccination and Control of Aujeszky's Disease pp. 107-117 (Exhibit 28).
- Meisner, B. Reviews of Infectious Diseases, vol. 13 (suppl. 11), pp. S895-S897, 1991.
- Riviere, M. et al. Journal of Virology, vol. 66, No. 6, pp. 3424-3434, Jun. 1992.