Methods for Treating Ulcerative Colitis

This application relates to anti-interleukin-8 (IL-8) antibodies and their use in the treatment of inflammatory disorders.

Interleukin-8 (IL-8) is a neutrophil chemotactic peptide secreted by a variety of cells in response to inflammatory mediators (for a review see Hebert et al., Cancer Investiaation 11(6):743 (1993)). IL-8 can play an important role in the pathogenesis of inflammatory disorders, such as adult respiratory distress syndrome (ARDS), septic shock, and multiple organ failure. Immune therapy for such inflammatory disorders can include treatment of an affected patient with anti-IL-8 antibodies.

Sticherling et al. (J. immunol. 143:1628 (1989)) disclose the production and characterization of four monoclonal antibodies against IL-8. WO 92/04372, published Mar. 19, 1992, discloses polyclonal antibodies which react with the receptor-interacting site of IL-8 and peptide analogs of IL-8, along with the use of such antibodies to prevent an inflammatory response in patients. St. John et al. (Chest 103:932 (1993)) review immune therapy for ARDS, septic shock, and multiple organ failure, including the potential therapeutic use of anti-IL-8 antibodies. Sekido et al. (Nature 365:654 (1993)) disclose the prevention of lung reperfusion injury in rabbits by a monoclonal antibody against IL-8. Mulligan et al. (J. Immunol. 150:5585 (1993)), disclose protective effects of a murine monoclonal antibody to human IL-8 in inflammatory lung injury in rats.

The instant invention demonstrates that the anti-IL-8 monoclonal antibodies of the invention can be used therapeutically in the treatment of other inflammatory disorders, such as bacterial pneumonias and inflammatory bowel disease.

Anti-IL-8 antibodies are additionally useful as reagents for assaying IL-8. For example, Sticherling et al. (Arch. Dermatol. Res. 284:82 (1992)), disclose the use of anti-IL-8 monoclonal antibodies as reagents in immunohistochemical studies. Ko et al. (J. Immunol. Methods 149:227 (1992)) disclose the use of anti-IL-8 monoclonal antibodies as reagents in an enzyme-linked immunoabsorbent assay (ELISA) for IL-8.

One aspect of the invention is an anti-IL-8 monoclonal antibody having the following characteristics: ability to bind human IL-8 with a K.sub.d between about 1.times.10.sup.-8 to about 1.times.10.sup.-10 M, ability to inhibit neutrophil chemotaxis in response to IL-8, and ability to inhibit IL-8 mediated elastase release by neutrophils; wherein the monoclonal antibody does not bind to C5a, .beta.-TG or platelet factor 4.

Another aspect of the invention is the plasmid pantiIL-8.2. Further aspects of the invention are the Fab encoded by pantiIL-8.2 and an antibody fragment selected from the group consisting of Fab, Fab', Fab'-SH, Fv, or F(ab').sub.2, wherein the antibody fragment has the complementarity determining regions encoded by pantiIL-8.2.

Another aspect of the invention is the plasmid p6G425chim2. Further aspects of the invention are the Fab encoded by p6G425chim2 and an antibody fragment selected from the group consisting of Fab, Fab', Fab'-SH, Fv, or F(ab').sub.2, wherein the antibody fragment has the complementarity determining regions encoded by p6G425chim2.

Another aspect of the invention is method of treating ulcerative colitis in a mammal comprising administering a therapeutically effective amount of the anti-IL-8 antibodies of the invention.

Another aspect of the invention is a method of treating bacterial pneumonia in a mammal comprising administering a therapeutically effective amount of the anti-IL-8 antibodies of the invention.

FIG. 1 is a graph depicting the blocking of IL-8 mediated elastase release by neutrophils by anti-IL-8 monoclonal antibody 5.12.14.

FIG. 2 is a graph depicting the inhibition of .sup.125 I-IL-8 binding to neutrophils by unlabeled IL-8.

FIG. 3 demonstrates a negative isotype matched Fab does not inhibit the binding of .sup.125 I-IL-8 to human neutrophils.

FIG. 4 is a graph depicting the inhibition of binding of .sup.125 I-IL-8 to human neutrophils by chimeric 5.12.14 Fab with an average IC.sub.50 of 1.6 nM.

FIG. 5 is a graph depicting the inhibition of binding of .sup.125 I-IL-8 to human neutrophils by chimeric 6G.4.25 Fab with an average IC.sub.50 of 7.5 nM.

FIG. 6 demonstrates the inhibition of human IL-8 mediated neutrophil chemotaxis by chimeric 6G4.2.5 Fab and chimeric 5.12.14 Fab.

FIG. 7 demonstrates the relative abilities of chimeric 6G4.2.5 Fab and chimeric 5.12.14 Fab to inhibit rabbit IL-8 mediated neutrophil chemotaxis.

FIG. 8 depicts the stimulation of elastase release from human neutrophils by various concentrations of human and rabbit IL-8. The relative extent of elastase release was guantitated by measurement of absorbance at 405 nm. The data represent mean .+-. SEM of triplicate samples.

FIG. 9 is a graph depicting the ability of chimeric 6G4.2.5 Fab and chimeric 5.12.14 Fab to inhibit elastase release from human neutrophils stimulated by human IL-8. The results were normalized to reflect the percentage of elastase release elicited by 100 nM IL-8 alone. The data represent the mean .+-. SEM of three separate experiments performed on different days with different blood donors. IC.sub.50 values were calculated by four parameter fit.

FIG. 10 is a graph depicting the relative abilities of chimeric 6G4.2.5 Fab and chimeric 5.12.14 Fab to inhibit elastase release from human neutrophils stimulated by rabbit IL-8. The results were normalized to reflect the percentage of elastase release elicited by 100 nM IL-8 alone. The data represent the mean .+-. SEM of three separate experiments performed on different days with different blood donors. IC.sub.50 values were calculated by four parameter fit.

FIGS. 11A-11J are a set of graphs depicting the following parameters in a rabbit ulcerative colitis model: FIG. 11A depicts myeloperoxidase Levels in tissue; FIG. 11B depicts IL-8 levels in tissue; FIG. 11C depicts colon weight; FIG. 11D depicts gross inflammation; FIG. 11E depicts edema; FIG. 11F depicts extent of necrosis; FIG. 11G depicts severity of necrosis; FIG. 11H depicts neutrophil margination; FIG. 11J depicts neutrophil infiltration; and FIG. 11J depicts mononuclear infiltration.

FIG. 12 is a graph depicting the effect of anti-IL-8 monoclonal antibody treatment on the number of neutrophils in bronchoalveolar lavage (BAL) fluid in animals infected with Streptococcus pneumoniae, Escherichia coli, or Pseudomonas aeruginosa. Treatment with 6G4.2.5 significantly reduced the number of neutrophils present in the BAL fluid compared to animals treated with isotype control mouse IgG (FIG. 12).

FIG. 13 depicts the DNA sequences of three primers designed for each of the light and heavy chains. Multiple primers were designed in order to increase the chances of primer hybridization and efficiency of first strand cDNA synthesis for cloning the variable light and heavy regions of monoclonal antibody 5.12.14.

FIG. 14 depicts the DNA sequences of one forward primer and one reverse primer for the 5.12.14 light chain variable region amplification.

FIG. 15 depicts the DNA sequences of one forward primer and one reverse primer for the 5.12.14 heavy chain variable region amplification.

FIG. 16 depicts the DNA sequence of the 5.12.14 light chain variable region. CDRs are indicated by either X-ray crystallography (underlined amino acids) or by Kabat sequence comparison (amino acids denoted with asterisk). Important restriction sites are indicated in italics. The signal peptide of STII is amino acids -23 to -1. The murine variable light region is amino acids 1 to 109. The partial murine constant light region is amino acids 110 to 123 (in italics).

FIG. 17 depicts the DNA sequence of the 5.12.14 heavy chain variable region. CDRs are indicated by either X-ray crystallography (underlined amino acids) or by Kabat sequence comparison (amino acids denoted with asterisk). Important restriction sites are indicated in italics. The signal peptide of STII is amino acids -23 to -1. The murine variable heavy region is amino acids 1 to 120. The partial murine constant heavy region is amino acids 121 to 130.

FIG. 18 depicts the DNA sequences of amplification primers used to convert murine light and heavy chain constant region residues to their human equivalents.

FIG. 19 depicts the coding sequence for the 5.12.14 light chain variable region and the human IgG1 light chain constant region. CDRs are indicated by either X-ray crystallography (underlined amino acids) or by Kabat sequence comparison (amino acids denoted with asterisk). The human constant region is denoted in italics. The signal peptide of STII is amino acids -23 to -1. The murine variable light region is amino acids 1 to 109. The human constant light region is amino acids 110 to 215.

FIG. 20A-20B depict the coding sequence for the 5.12.14 heavy chain variable region and the heavy chain constant region of human IgG1. FIG. 20A and 20B depict nucleotides 1-660 and 661-756 of the nucleic acid sequence SEQ ID NO:29, respectively, and amino acids 1-220 and 221-251 of the amino acid sequence SEQ ID NO:30, respectively. CDRs are indicated by either X-ray crystallography (underlined amino acids) or by Kabat sequence comparison (amino acids denoted with asterisk) in FIG. 20A. The human constant region is denoted in italics in FIGS. 20A-20B. The signal peptide of STII is amino acids -23 to -1 in FIG. 20A. The murine variable heavy region is amino acids 1 to 120 in FIG. 20A. The human constant heavy region is amino acids 121 to 228 in FIGS. 20A-20B.

FIG. 21 depicts the DNA sequences of three primers designed for each of the light and heavy chains. Multiple primers were designed in order to increase the chances of primer hybridization and efficiency of first strand cDNA synthesis for cloning the variable light and heavy regions of monoclonal antibody 6G4.2.5.

FIG. 22 depicts the DNA sequences of one forward primer and one reverse primer for the 6G4.2.5 light chain variable region amplification.

FIG. 23 depicts the DNA sequences of one forward primer and one reverse primer for the 6G4.2.5 heavy chain variable region amplification.

FIG. 24 depicts the DNA sequence of the 6G4.2.5 light chain variable region. CDRs are indicated by either X-ray crystallography (underlined amino acids) or by Kabat sequence comparison (amino acids denoted with asterisk). Useful cloning sites are in italics. The signal peptide of STII is amino acids -23 to -1. The murine variable light region is amino acids 1 to 114. The partial murine constant light region is amino acids 115 to 131.

FIG. 25 depicts the DNA sequence of the 6G4.2.5 heavy chain variable region. CDRs are indicated by either X-ray crystallography (underlined amino acids) or by Kabat sequence comparison (amino acids denoted with asterisk). Useful cloning sites are in italics. The signal peptide of STII is amino acids -23 to -1. The murine variable heavy region is amino acids 1 to 122. The partial murine constant heavy region is amino acids 123 to 135.

FIG. 26 depicts primers to convert the murine light chain and heavy chain constant regions to their human equivalents.

FIGS. 27A-27B depict the coding sequence for the chimeric 6G4.2.5 light chain. FIG. 27A and 27B depict nucleotides 1-660 and 661-729 of the nucleic acid sequence SEQ ID NO:55, respectively, and amino acids 1-220 and 221-242 of the amino acid sequence SEQ ID NO:56, respectively. CDRs are indicated by either X-ray crystallography (underlined amino acids) or by Kabat sequence comparison (amino acids denoted with asterisk) in FIG. 27A. The human constant region is denoted in italics in FIGS 27A-27B. The signal peptide of STII is amino acids -23 to -1 in FIG. 27A. The murine variable heavy region is amino acids 1 to 114 in FIG. 27A. The human constant heavy region is amino acids 115 to 219 in FIGS. 27A-27B.

FIG. 28A-28B depict the coding sequence for the chimeric 6G4.2.5 heavy chain. FIGS. 28A and 28B depict nucleotides 1-660 and 661-762 of the nucleic acid seguence SEQ ID NO:57, respectively, and amino acids 1-220 and 221-253 of the amino acid sequence SEQ ID NO:58, respectively. CDRs are indicated by either X-ray crystallography (underlined amino acids) or by Kabat sequence comparison (amino acids denoted with asterisk) in FIG. 28A. The human constant region is denoted in italics in FIGS. 28A-28B. The signal peptide of STII is amino acids -23 to -1 in FIG. 28A. The murine variable heavy region is amino acids 1 to 122 in FIG. 28A. The human constant heavy region is amino acids 123 to 230 in FIGS. 28A-28B.

In general, the following words or phrases have the indicated definition when used in the description, examples, and claims.

"Polymerase chain reaction" or "PCR" refers to a procedure or technique in which minute amounts of a specific piece of nucleic acid, RNA and/or DNA, are amplified as described in U.S. Pat. No. 4,683,195 issued 28 Jul. 1987. Generally, sequence information from the ends of the region of interest or beyond needs to be available, such that oligonucleotide primers can be designed; these primers will be identical or similar in sequence to opposite strands of the template to be amplified. The 5' terminal nucleotides of the two primers can coincide with the ends of the amplified material. PCR can be used to amplify specific RNA sequences, specific DNA sequences from total genomic DNA, and cDNA transcribed from total cellular RNA, bacteriophage or plasmid sequences, etc. See generally Mullis et al., Cold Soring Harbor Symp. Ouant. Biol. 51:263 (1987); Erlich, ed., PCR Technology (Stockton Press, N.Y., 1989). As used herein, PCR is considered to be one, but not the only, example of a nucleic acid polymerase reaction method for amplifying a nucleic acid test sample comprising the use of a known nucleic acid as a primer and a nucleic acid polymerase to amplify or generate a specific piece of nucleic acid.

"Antibodies" (Abs) and "immunoglobulins" (Igs) are glycoproteins having the same structural characteristics. While antibodies exhibit binding specificity to a specific antigen, immunoglobulins include both antibodies and other antibody-like molecules which lack antigen specificity. Polypeptides of the latter kind are, for example, produced at low levels by the lymph system and at increased levels by myelomas.

"Native antibodies and immunoglobulins" are usually heterotetrameric glycoproteins of about 150,000 daltons, composed of two identical light (L) chains and two identical heavy (H) chains. Each light chain is linked to a heavy chain by one covalent disulfide bond, while the number of disulfide linkages varies between the heavy chains of different immunoglobulin isotypes. Each heavy and light chain also has regularly spaced intrachain disulfide bridges. Each heavy chain has at one end a variable domain (V.sub.H) followed by a number of constant domains. Each light chain has a variable domain at one end (V.sub.L) and a constant domain at its other end; the constant domain of the lof the light chain is aligned with the first constant domain of the heavy chain, and the light chain variable domain is aligned with the variable domain of the heavy chain. Particular amino acid residues are believed to form an interface between the light- and heavy-chain variable domains (Clothia et al., J. Mol. Biol. 186:651 (1985); Novotny and Haber, Proc. Natl. Acad. Sci. U.S.A. 82:4592 (1985)).

The term "variable" refers to the fact that certain portions of the variable domains differ extensively in sequence among antibodies and are used in the binding and specificity of each particular antibody for its particular antigen. However, the variability is not evenly distributed throughout the variable domains of antibodies. It is concentrated in three segments called complementarity-determining regions (CDRs) or hypervariable regions both in the light-chain and the heavy-chain variable domains. The more highly conserved portions of variable domains are called the framework (FR). The variable domains of native heavy and light chains each comprise four FR regions, largely adopting a .beta.-sheet configuration, connected by three CDRs, which form loops connecting, and in some cases forming part of, the .beta.-sheet structure. The CDRs in each chain are held together in close proximity by the FR regions and, with the CDRs from the other chain, contribute to the formation of the antigen-binding site of antibodies (see Kabat et al., Sequences of Proteins of Immunological Interest, Fifth Edition, National Institute of Health, Bethesda, Md. (1991)). The constant domains are not involved directly in binding an antibody to an antigen, but exhibit various effector functions, such as participation of the antibody in antibody-dependent cellular toxicity.

Papain digestion of antibodies produces two identical antigen-binding fragments, called "Fab" fragments, each with a single antigen-binding site, and a residual "Fc" fragment, whose name reflects its ability to crystallize readily. Pepsin treatment yields an F(ab').sub.2 fragment that has two antigen-combining sites and is still capable of cross-linking antigen.

"Fv" is the minimum antibody fragment which contains a complete antigen-recognition and -binding site. This region consists of a dimer of one heavy--and one light-chain variable domain in tight, non-covalent association. It is in this configuration that the three CDRs of each variable domain interact to define an antigen-binding site on the surface of the V.sub.H -V.sub.L dimer. Collectively, the six CDRs confer antigen-binding specificity to the antibody. However, even a single variable domain (or half of an Fv comprising only three CDRs specific for an antigen) has the ability to recognize and bind antigen, although at a lower affinity than the entire binding site.

The Fab fragment also contains the constant domain of the light chain and the first constant domain (CH1) of the heavy chain. Fab' fragments differ from Fab fragments by the addition of a few residues at the carboxy terminus of the heavy chain CH1 domain including one or more cysteines from the antibody hinge region. Fab'-SH is the designation herein for Fab' in which the cysteine residue(s) of the constant domains bear a free thiol group. F(ab').sub.2 antibody fragments originally were produced as pairs of Fab' fragments which have hinge cysteines between them. Other chemical couplings of antibody fragments are also known.

The "light chains" of antibodies (immunoglobulins) from any vertebrate species can be assigned to one of two clearly distinct types, called kappa (k) and lambda (1), based on the amino acid sequences of their constant domains.

Depending on the amino acid sequence of the constant domain of their heavy chains, immunoglobulins can be assigned to different classes. There are five major classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, and several of these can be further divided into subclasses (isotypes), e.g., IgG.sub.1, IgG.sub.2, IgG.sub.3, IgG.sub.4, IgA.sub.1, and IgA.sub.2. The heavy-chain constant domains that correspond to the different classes of immunoglobulins are called .alpha., .delta., .epsilon., .gamma., and .mu., respectively. The subunit structures and three-dimensional configurations of different classes of immunoglobulins are well known.

The term "antibody" is used in the broadest sense and specifically covers single monoclonal antibodies (including agonist and antagonist antibodies) and antibody compositions with polyepitopic specificity. The term "monoclonal antibody" (mAb) as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, i.e., the individual antibodies comprising the population are identical except for possible naturally occurring mutations that may be present in minor amounts. Monoclonal antibodies are highly specific, being directed against a single antigenic site. Furthermore, in contrast to conventional (polyclonal) antibody preparations which typically include different antibodies directed against different determinants (epitopes), each mAb is directed against a single determinant on the antigen. In addition to their specificity, the monoclonal antibodies are advantageous in that they can be synthesized by hybridoma culture, uncontaminated by other immunoglobulins.

The monoclonal antibodies herein include hybrid and recombinant antibodies produced by splicing a variable (including hypervariable) domain of an anti-IL-8 antibody with a constant domain (e.g. "humanized" antibodies), or a light chain with a heavy chain, or a chain from one species with a chain from another species, or fusions with heterologous proteins, regardless of species of origin or immunoglobulin class or subclass designation, as well as antibody fragments (e.g., Fab, F(ab').sub.2, and Fv), so long as they exhibit the desired biological activity. (See, e.g., Cabilly et al., U.S. Pat. No. 4,816,567; Mage and Lamoyi, in Monoclonal Antibody Production Techniques and Applications, pp. 79-97 (Marcel Dekker, Inc., New York, 987).)

Thus, the modifier "monoclonal" indicates the character of the antibody as being obtained from a substantially homogeneous population of antibodies, and is not to be construed as requiring production of the antibody by any particular method. For example, the monoclonal antibodies to be used in accordance with the present invention can be made by the hybridoma method first described by Kohler and Milstein, Nature 256:495 (1975), or can be made by recombinant DNA methods (Cabilly et al., supra).

The monoclonal antibodies herein specifically include "chimeric" antibodies (immunoglobulins) in which a portion of the heavy and/or light chain is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity (Cabilly et al., supra; Morrison et al., Proc. Natl. Acad. Sci. U.S.A. 81:6851 (1984)).

"Humanized" forms of non-human (e.g., murine) antibodies are specific chimeric immunoglobulins, immunoglobulin chains or fragments thereof (such as Fv, Fab, Fab', F(ab').sub.2, or other antigen-binding subsequences of antibodies) which contain minimal sequence derived from non-human immunoglobulin. For the most part, humanized antibodies are human immunoglobulins (recipient antibody) in which residues from a complementary-determining region (CDR) of the recipient are replaced by residues from a CDR of a non-human species (donor antibody) such as mouse, rat, or rabbit having the desired specificity, affinity, and capacity. In some instances, Fv framework residues of the human immunoglobulin are replaced by corresponding non-human residues. Furthermore, humanized antibodies can comprise residues which are found neither in the recipient antibody nor in the imported CDR or framework sequences. These modifications are made to further refine and optimize antibody performance. In general, the humanized antibody will comprise substantially all of at least one, and typically two, variable domains, in which all or substantially all of the CDR regions correspond to those of a non-human immunoglobulin and all or substantially all of the FR regions are those of a human immunoglobulin consensus sequence. The humanized antibody optimally also will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin. For further details see Jones et al., Nature 321:522 (1986); Reichmann et al., Nature 332:323 (1988); and Presta, Curr. Op. Strut, Biol. 2:593 (1992).

"Treatment" refers to both therapeutic treatment and prophylactic or preventative measures. Those in need of treatment include those already with the disorder as well as those prone to have the disorder or those in which the disorder is to be prevented.

"Mammal" for purposes of treatment refers to any animal classified as a mammal, including humans, domestic and farm animals, and zoo, sports, or pet animals, such as dogs, horses, cats, cows, etc. Preferably, the mammal herein is human.

As used herein, protein, peptide and polypeptide are used interchangeably to denote an amino acid polymer or a set of two or more interacting or bound amino acid polymers.

As used herein, the term "inflammatory disorders" refers to pathological states resulting in inflammation, typically caused by neutrophil chemotaxis. Examples of such disorders include inflammatory skin diseases including psoriasis; responses associated with inflammatory bowel disease (such as Crohn's disease and ulcerative colitis); ischemic reperfusion; adult respiratory distress syndrome; dermatitis; meningitis; encephalitis; uveitis; autoimmune diseases such as rheumatoid arthritis, Sjorgen's syndrome, vasculitis; diseases involving leukocyte diapedesis; central nervous system (CNS) inflammatory disorder, multiple organ injury syndrome secondary to septicaemia or trauma; alcoholic hepatitis, bacterial pneumonia, antigen-antibody complex mediated diseases; inflammations of the lung, including pleurisy, alveolitis, vasculitis, pneumonia, chronic bronchitis, bronchiectasis, and cystic fibrosis; etc. The preferred indications are bacterial pneumonia and inflammatory bowel disease such as ulcerative colitis.

1. Anti-IL-8 Antibody Preparation

a. Monoclonal Antibodies

The anti-IL-8 antibodies of the invention are preferably monoclonal, binding IL-8 with a K.sub.d of about 1.times.10.sup.-8 to 1.times.10.sup.-11, more preferably, 1.times.10.sup.-9 to 1.times.10.sup.-10. The antibodies of the invention preferably do not measurably bind in an ELISA assay to chemokines other than IL-8, such as C5a, platelet factor 4 or .beta.-TG. Furthermore, the antibodies of the invention preferably inhibit elastase release from IL-8 stimulated neutrophils and inhibit IL-8 stimulated chemotaxis of neutrophils. In one embodiment of the invention, the antibodies of the invention can bind IL-8 from non-human species in addition to human IL-8, such as rabbit IL-8.

In another embodiment of the invention, Fab, Fab', Fab'-SH, or F(ab').sub.2 fragments of the anti-IL-8 antibodies of the instant invention are created. These antibody "fragments" can be created by traditional means, such as enzymatic digestion, or may be generated by recombinant techniques. Such antibody fragments may be chimeric or humanized. These fragments are useful for the diagnostic and therapeutic purposed set forth below.

The anti-IL-8 monoclonal antibodies of the invention can be made, for example, using the hybridoma method first described by Kohler and Milstein, Nature 256:495 (1975), or can be made by recombinant DNA methods (Cabilly et al., supra).

In the hybridoma method, a mouse or other appropriate host animal, such as a hamster, is immunized as herein above described to elicit lymphocytes that produce or are capable of producing antibodies that will specifically bind to the IL-8 or IL-8 fragment used for immunization. Antibodies to IL-8 generally are raised in animals by multiple subcutaneous (sc) or intraperitoneal (ip) injections of the IL-8 and an adjuvant. Animals ordinarily are immunized against immunogenic conjugates or derivatives of IL-8 with monophosphoryl lipid A (MPL)/trehalose dicorynomycolate (TDM) (Ribi Immunochem. Research, Inc., Hamilton, Mont.) and the solution is injected intradermally at multiple sites. Two weeks later the animals are boosted. 7 to 14 days later animals are bled and the serum is assayed for anti-IL-8 titer. Animals are boosted until the titer plateaus.

Alternatively, lymphocytes can be immunized in vitro. Lymphocytes then are fused with myeloma cells using a suitable fusing agent, such as polyethylene glycol, to form a hybridoma cell (Goding, Monoclonal Antibodies: Principles and Practice and pp. 59-103 (Academic Press, 1986)).

The hybridoma cells thus prepared are seeded and grown in a suitable culture medium that preferably contains one or more substances that inhibit the growth or survival of the unfused, parental myeloma cells. For example, if the parental myeloma cells lack the enzyme hypoxanthine guanine phosphoribosyl transferase (HGPRT or HPRT), the culture medium for the hybridomas typically will include hypoxanthine, aminopterin, and thymidine (HAT medium), which substances prevent the growth of HGPRT-deficient cells.

Preferred myeloma cells are those that fuse efficiently, support stable high-level production of antibody by the selected antibody-producing cells, and are sensitive to a medium such as HAT medium. Among these, preferred myeloma cell lines are murine myeloma lines, such as those derived from MOPC-21 and MPC-11 mouse tumors available from the Salk Institute Cell Distribution Center, San Diego, Calif. U.S.A., and SP-2 cells available from the American Type Culture Collection, Rockville, Md. U.S.A.

Culture medium in which hybridoma cells are growing is assayed for production of monoclonal antibodies directed against IL-8. Preferably, the binding specificity of monoclonal antibodies produced by hybridoma cells is determined by immunoprecipitation or by an in vitro binding assay, such as radioimmunoassay (RIA) or enzyme-linked immunoabsorbent assay (ELISA).

The binding affinity of the mAbs can, for example, be determined by the Scatchard analysis of Munson and Pollard, Anal. Biochem. 107:220 (1980).

After hybridoma cells are identified that produce antibodies of the desired specificity, affinity, and/or activity, the clones can be subcloned by limiting dilution procedures and grown by standard methods (Goding, supra). Suitable culture media for this purpose include, for example, D-MEM or RPMI-1640 medium. In addition, the hybridoma cells can be grown in vivo as ascites tumors in an animal.

The monoclonal antibodies secreted by the subclones are suitably separated from the culture medium, ascites fluid, or serum by conventional immunoglobulin purification procedures such as, for example, protein A-Sepharose, hydroxylapatite chromatography, gel electrophoresis, dialysis, or affinity chromatography.

DNA encoding the monoclonal antibodies of the invention is readily isolated and sequenced using conventional procedures (e.g., by using oligonucleotide probes that are capable of binding specifically to genes encoding the heavy and light chains of murine antibodies). The hybridoma cells of the invention serve as a preferred source of such DNA. Once isolated, the DNA can be placed into expression vectors, which are then transfected into host cells such as E. coli cells, simian COS cells, Chinese hamster ovary (CHO) cells, or myeloma cells that do not otherwise produce immunoglobulin protein, to obtain the synthesis of monoclonal antibodies in the recombinant host cells. Review articles on recombinant expression in bacteria of DNA encoding the antibody include Skerra et al., Curr. Opinion in Immunol. 5:256 (1993) and Pluckthun Immunol. Revs. 130:151 (1992).

The DNA also can be modified, for example, by substituting the coding sequence for human heavy- and light-chain constant domains in place of the homologous murine sequences (e.g., Morrison et al., Proc. Natl. Acad. Sci. 81:6851 (1984)), or by covalently joining to the immunoglobulin coding sequence all or part of the coding sequence for a non-immunoglobulin polypeptide. In that manner, "chimeric" or "hybrid" antibodies are prepared that have the binding specificity of an anti-IL-8 mAb herein.

Typically, such non-immunoglobulin polypeptides are substituted for the constant domains of an antibody of the invention, or they are substituted for the variable domains of one antigen-combining site of an antibody of the invention to create a chimeric bivalent antibody comprising one antigen-combining site having specificity for a IL-8 and another antigen-combining site having specificity for a different antigen.

Chimeric or hybrid antibodies also can be prepared in vitro using known methods in synthetic protein chemistry, including those involving crosslinking agents. For example, immunotoxins can be constructed using a disulfide-exchange reaction or by forming a thioether bond. Examples of suitable reagents for this purpose include iminothiolate and methyl-4-mercaptobutyrimidate.

b. Humanized Antibodies

Methods for humanizing non-human antibodies are well known in the art. Generally, a humanized antibody has one or more amino acid residues introduced into it from a source which is non-human. These non-human amino acid residues are often referred to as "import" residues, which are typically taken from an "import" variable domain. Humanization can be essentially performed following the method of Winter and co-workers (Jones et al., Nature 321:522 (1986); Riechmann et al., Nature 332:323 (1988); Verhoeyen et al., Science 239:1534 (1988)), by substituting rodent CDRs or CDR sequences for the corresponding sequences of a human antibody. Accordingly, such "humanized" antibodies are chimeric antibodies (Cabilly et al., supra), wherein substantially less than an intact human variable domain has been substituted by the corresponding sequence from a non-human species. In practice, humanized antibodies are typically human antibodies in which some CDR residues and possibly some FR residues are substituted by residues from analogous sites in rodent antibodies.

The choice of human variable domains, both light and heavy, to be used in making the humanized antibodies is very important to reduce antigenicity. According to the so-called "best-fit" method, the sequence of the variable domain of a rodent antibody is screened against the entire library of known human variable-domain sequences. The human sequence which is closest to that of the rodent is then accepted as the human framework (FR) for the humanized antibody (Sims et al., J. Immunol. 151:2296 (1993); Chothia and Lesk, J. Mol. Biol. 196:901 (1987)). Another method uses a particular framework derived from the consensus sequence of all human antibodies of a particular subgroup of light or heavy chains. The same framework can be used for several different humanized antibodies (Carter et al., Proc. Natl. Acad. Sci. U.S.A. 89:4285 (1992); Presta et al., J. Immunol. 151:2623 (1993)).

It is further important that antibodies be humanized with retention of high affinity for the antigen and other favorable biological properties. To achieve this goal, according to a preferred method, humanized antibodies are prepared by a process of analysis of the parental sequences and various conceptual humanized products using three-dimensional models of the parental and humanized sequences. Three-dimensional immunoglobulin models are commonly available and are familiar to those skilled in the art. Computer programs are available which illustrate and display probable three-dimensional conformational structures of selected candidate immunoglobulin sequences. Inspection of these displays permits analysis of the likely role of the residues in the functioning of the candidate immunoglobulin sequence, i.e., the analysis of residues that influence the ability of the candidate immunoglobulin to bind its antigen. In this way, FR residues can be selected and combined from the consensus and import sequences so that the desired antibody characteristic, such as increased affinity for the target antigen(s), is achieved. In general, the CDR residues are directly and most substantially involved in influencing antigen binding.

c. Human Antibodies

Human monoclonal antibodies can be made by the hybridoma method. Human myeloma and mouse-human heteromyeloma cell lines for the production of human monoclonal antibodies have been described, for example, by Kozbor, J. Immunol. 133:3001 (1984); Brodeur et al., Monoclonal Antibody Production Techniques and Applications, pp. 51-63 (Marcel Dekker, Inc., New York, 1987); and Boerner et al., J. Immunol. 147:86 (1991).

It is now possible to produce transgenic animals (e.g., mice) that are capable, upon immunization, of producing a full repertoire of human antibodies in the absence of endogenous immunoglobulin production. For example, it has been described that the homozygous deletion of the antibody heavy-chain joining region (J.sub.H) gene in chimeric and germ-line mutant mice results in complete inhibition of endogenous antibody production. Transfer of the human germ-line immunoglobulin gene array in such germ-line mutant mice will result in the production of human antibodies upon antigen challenge. See, e.g., Jakobovits et al., Proc. Natl. Acad. Sci. U.S.A. 90:2551 (1993); Jakobovits et al. Nature 362:255 (1993); Bruggermann et al., Year in Immuno. 7:33 (1993).

Alternatively, phage display technology (McCafferty et al., Nature 348:552 (1990)) can be used to produce human antibodies and antibody fragments in vitro, from immunoglobulin variable (V) domain gene repertoires from unimmunized donors. According to this technique, antibody V domain genes are cloned in-frame into either a major or minor coat protein gene of a filamentous bacteriophage, such as M13 or fd, and displayed as functional antibody fragments on the surface of the phage particle. Because the filamentous particle contains a single-stranded DNA copy of the phage genome, selections based on the functional properties of the antibody also result in selection of the gene encoding the antibody exhibiting those properties. Thus, the phage mimics some of the properties of the B-cell. Phage display can be performed in a variety of formats; for their review see, e.g., Johnson et al., Current Opion in Structural Biology 3:564 (1993). Several sources of V-gene segments can be used for phage display. Clackson et al., Nature 352:624 (1991) isolated a diverse array of anti-oxazolone antibodies from a small random combinatorial library of V genes derived from the spleens of immunized mice. A repertoire of V genes from unimmunized human donors can be constructed and antibodies to a diverse array of antigens (including self-antigens) can be isolated essentially following the techniques described by Marks et al., J. Mol. Biol., 222:581 (1991), or Griffith et al., EMBO J. 12:725 (1993).

In a natural immune response, antibody genes accumulate mutations at a high rate (somatic hypermutation). Some of the changes introduced will confer higher affinity, and B cells displaying high-affinity surface immunoglobulin are preferentially replicated and differentiated during subsequent antigen challenge. This natural process can be mimicked by employing the technique known as "chain shuffling" (Marks et al., Bio/Technol. 10:779 (1992)). In this method, the affinity of "primary" human antibodies obtained by phage display can be improved by sequentially replacing the heavy and light chain V region genes with repertoires of naturally occurring variants (repertoires) of V domain genes obtained from unimmunized donors. This technique allows the production of antibodies and antibody fragments with affinities in the nM range. A strategy for making very large phage antibody repertoires has been described by Waterhouse et al., Nucl. Acids Res. 21:2265 (1993).

Gene shuffling can also be used to derive human antibodies from rodent antibodies, where the human antibody has similar affinities and specificities to the starting rodent antibody. According to this method, which is also referred to as "epitope imprinting", the heavy or light chain V domain gene of rodent antibodies obtained by phage display technique is replaced with a repertoire of human V domain genes, creating rodent-human chimeras. Selection with antigen results in isolation of human variable capable of restoring a functional antigen-binding site, i.e. the epitope governs (imprints) the choice of partner. When the process is repeated in order to replace the remaining rodent V domain, a human antibody is obtained (see PCT WO 93/06213, published 1 Apr. 1993). Unlike traditional humanization of rodent antibodies by CDR grafting, this technique provides completely human antibodies, which have no framework or CDR residues of rodent origin.

d. Bispecific Antibodies

Bispecific antibodies are monoclonal, preferably human or humanized, antibodies that have binding specificities for at least two different antigens. In the present case, one of the binding specificities is for IL-8, the other one is for any other antigen. For example, bispecific antibodies specifically binding a IL-8 and neurotrophic factor, or two different types of IL-8 polypeptides are within the scope of the present invention.

Methods for making bispecific antibodies are known in the art. Traditionally, the recombinant production of bispecific antibodies is based on the co-expression of two immunoglobulin heavy chain-light chain pairs, where the two heavy chains have different specificities (Milstein and Cuello, Nature 305:537 (1983)). Because of the random assortment of immunoglobulin heavy and light chains, these hybridomas (quadromas) produce a potential mixture of 10 different antibody molecules, of which only one has the correct bispecific structure. The purification of the correct molecule, which is usually done by affinity chromatography steps, is rather cumbersome, and the product yields are low. Similar procedures are disclosed in WO 93/08829 published 13 May 1993, and in Traunecker et al., EMBO J. 10:3655 (1991).

According to a different and more preferred approach, antibody-variable domains with the desired binding specificities (antibody-antigen combining sites) are fused to immunoglobulin constant-domain sequences. The fusion preferably is with an immunoglobulin heavy-chain constant domain, comprising at least part of the hinge, CH2, and CH3 regions. It is preferred to have the first heavy-chain constant region (CH1), containing the site necessary for light-chain binding, present in at least one of the fusions. DNAs encoding the immunoglobulin heavy chain fusions and, if desired, the immunoglobulin light chain, are inserted into separate expression vectors, and are co-transfected into a suitable host organism. This provides for great flexibility in adjusting the mutual proportions of the three polypeptide fragments in embodiments when unequal ratios of the three polypeptide chains used in the construction provide the optimum yields. It is, however, possible to insert the coding sequences for two or all three polypeptide chains in one expression vector when the production of at least two polypeptide chains in equal ratios results in high yields or when the ratios are of no particular significance. In a preferred embodiment of this approach, the bispecific antibodies are composed of a hybrid immunoglobulin heavy chain with a first binding specificity in one arm, and a hybrid immunoglobulin heavy chain-light chain pair (providing a second binding specificity) in the other arm. This asymmetric structure facilitates the separation of the desired bispecific compound from unwanted immunoglobulin chain combinations, as the presence of an immunoglobulin light chain in only one half of the bispecific molecule provides for a facile way of separation. For further details of generating bispecific antibodies, see, for example, Suresh et al., Methods in Enzymology 121:210 (1986).

e. Heteroconjugate Antibodies

Heteroconjugate antibodies are also within the scope of the present invention. Heteroconjugate antibodies are composed of two covalently joined antibodies. Such antibodies have, for example, been proposed to target immune system cells to unwanted cells (U.S. Pat. No. 4,676,980), and for treatment of HIV infection (WO 91/00360; WO 92/00373; and EP 03089). Heteroconjugate antibodies can be made using any convenient cross-linking methods. Suitable cross-linking agents are well known in the art, and are disclosed in U.S. Pat. No. 4,676,980, along with a number of cross-linking techniques.

2. Uses of Anti-IL-8 Antibodies

a. Diagnostic Uses

For diagnostic applications requiring the detection or quantitation of IL-8, the antibodies of the invention typically will be labeled with a detectable moiety. The detectable moiety can be any one which is capable of producing, either directly or indirectly, a detectable signal. For example, the detectable moiety can be a radioisotope, such as .sup.3 H, .sup.14 C, .sup.32 P, .sup.35 S, or .sup.125 I; a fluorescent or chemiluminescent compound, such as fluorescein isothiocyanate, rhodamine, or luciferin; radioactive isotopic labels, such as, e.g., .sup.125 I, .sup.32 P, .sup.14 C, or .sup.3 H; or an enzyme, such as alkaline phosphatase, beta-galactosidase, or horseradish peroxidase.

Any method known in the art for separately conjugating the antibody to the detectable moiety can be employed, including those methods described by Hunter et al., Nature 144:945 (1962); David et al., Biocmemistry 13:1014 (1974); Pain et al., J. Immunol. Meth. 40:219 (1981); and Nygren, . J. Histochem. and Cytochem. 30:407 (1982).

The antibodies of the present invention can be employed in any known assay method, such as competitive binding assays, direct and indirect sandwich assays, and immunoprecipitation assays. For example, see Zola, Monoclonal Antibodies: A Manual of Techniques, pp. 147-158 (CRC Press, inc., 1987).

Competitive binding assays rely on the ability of a labeled standard (which can be a IL-8 or an immunologically reactive portion thereof) to compete with the test sample analyte (IL-8) for binding with a limited amount of antibody. The amount of IL-8 in the test sample is inversely proportional to the amount of standard that becomes bound to the antibodies. To facilitate determining the amount of standard that becomes bound, the antibodies generally are insolubilized before or after the competition, so that the standard and analyte that are bound to the antibodies can conveniently be separated from the standard and analyte which remain unbound.

Sandwich assays involve the use of two antibodies, each capable of binding to a different antigenic portion, or epitope, of the protein (IL-8) to be detected. In a sandwich assay, the test sample analyte is bound by a first antibody which is immobilized on a solid support, and thereafter a second antibody binds to the analyte, thus forming an insoluble three-part complex (U.S. Pat. No. 4,376,110). The second antibody can itself be labeled with a detectable moiety (direct sandwich assays) or can be measured using an anti-immunoglobulin antibody that is labeled with a detectable moiety (indirect sandwich assay). For example, one type of sandwich assay is an ELISA assay, in which case the detectable moiety is an enzyme (e.g., horseradish peroxidase).

IL-8 antibodies also are useful for the affinity purification of IL-8 from recombinant cell culture or natural sources. For example, these antibodies can be fixed to a solid support by techniques well known in the art so as to purify IL-8 from a source such as culture supernatant or tissue.

b. Therapeutic Compositions and Administration of Anti-IL-8 Antibody

Therapeutic formulations of anti-IL-8 antibodies are prepared for storage by mixing anti-IL-8 antibody having the desired degree of purity with optional physiologically acceptable carriers, excipients, or stabilizers (Remington's Pharmaceutical Sciences, supra), in the form of lyophilized cake or aqueous solutions. Acceptable carriers, excipients or stabilizers are nontoxic to recipients at the dosages and concentrations employed, and include buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid; low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such as sodium; and/or nonionic surfactants such as Tween, Pluronics or polyethylene glycol (PEG).

The anti-IL-8 mAb to be used for in vivo administration must be sterile. This is readily accomplished by filtration through sterile filtration membranes, prior to or following lyophilization and reconstitution. The anti-IL-8 mAb ordinarily will be stored in lyophilized form or in solution.

Therapeutic anti-IL-8 mAb compositions generally are placed into a container having a sterile access port, for example, an intravenous solution bag or vial having a stopper pierceable by a hypodermic injection needle.

The route of anti-IL-8 mAb administration is in accord with known methods, e.g., inhalation, injection or infusion by intravenous, intraperitoneal, intracerebral, intramuscular, intraocular, intraarterial, or intralesional routes, by enema or suppository, or by sustained release systems as noted below. Preferably the antibody is given systemically or at a site of inflammation.

Suitable examples of sustained-release preparations include semipermeable polymer matrices in the form of shaped articles, e.g. films, or microcapsules. Sustained release matrices include polyesters, hydrogels, polylactides (U.S. Pat. No. 3,773,919, EP 58,481), copolymers of L-glutamic acid and gamma ethyl-L-glutamate (Sidman et al., Biopolymers 22:547 (1983)), poly (2-hydroxyethyl-methacrylate) (Langer et al.,. J. Biomed. Mater. Res. 15:167 (1981) and Langer, Chem. Tech. 12:98 (1982)), ethylene vinyl acetate (Langer et al., supra) or poly-D-(-)-3-hydroxybutyric acid (EP 133,988). Sustained-release anti-IL-8 antibody compositions also include liposomally entrapped anti-IL-8 antibody. Liposomes containing anti-IL-8 antibody are prepared by methods known per se: DE 3,218,121; Epstein et al., Proc. Natl. Acad. Sci. U.S.A. 82:3688 (1985); Hwang et al., Proc. Natl. Acad. Sci U.S.A. 77:4030 (1980); EP 52,322; EP 36,676; EP 88,046; EP 143,949; EP 142,641; Japanese patent application 83-118008; U.S. Pat. Nos. 4,485,045 and 4,544,545; and EP 102,324. Ordinarily the liposomes are of the small (about 200-800 Angstroms) unilamelar type in which the lipid content is greater than about 30 mole percent cholesterol, the selected proportion being adjusted for the optimal anti-IL-8 antibody therapy.

An "effective amount" of anti-IL-8 antibody to be employed therapeutically wily depend, for example, upon the therapeutic objectives, the route of administration, and the condition of the patient. Accordingly, it will be necessary for the therapist to titer the dosage and modify the route of administration as required to obtain the optimal therapeutic effect. Typically, the clinician will administer the anti-iL-8 antibody until a dosage is reached that achieves the desired effect. The progress of this therapy is easily monitored by conventional assays.

In the treatment and prevention of an inflammatory disorder by an anti-IL-8 antibody, the antibody composition will be formulated, dosed, and administered in a fashion consistent with good medical practice. Factors for consideration in this context include the particular disorder being treated, the particular mammal being treated, the clinical condition of the individual patient, the cause of the disorder, the site of delivery of the antibody, the particular type of antibody, the method of administration, the scheduling of administration, and other factors known to medical practitioners. The "therapeutically effective amount" of antibody to be administered will be governed by such considerations, and is the minimum amount necessary to prevent, ameliorate, or treat the inflammatory disorder, including treating acute or chronic respiratory diseases and reducing inflammatory responses. Such amount is preferably below the amount that is toxic to the host or renders the host significantly more susceptible to infections.

As a general proposition, the initial pharmaceutically effective amount of the antibody administered parenterally per dose will be in the range of about 0.1 to 50 mg/kg of patient body weight per day, with the typical initial range of antibody used being 0.3 to 20 mg/kg/day, more preferably 0.3 to 15 mg/kg/day.

As noted above, however, these suggested amounts of antibody are subject to a great deal of therapeutic discretion. The key factor in selecting an appropriate dose and scheduling is the result obtained, as indicated above.

The antibody need not be, but is optionally formulated with one or more agents currently used to prevent or treat the inflammatory disorder in question. For example, in rheumatoid arthritis, the antibody can be given in conjunction with a glucocorticosteroid. The effective amount of such other agents depends on the amount of IL-8 antibody present in the formulation, the type of disorder or treatment, and other factors discussed above. These are generally used in the same dosages and with administration routes as used hereinbefore or about from 1 to 99% of the heretofore employed dosages.

The following examples are offered by way of illustration and not by way of limitation. The disclosures of all citations in the specification are expressly incorporated herein by reference.

Balb/c mice were immunized in each hind footpad or intraperitoneally with 10 .mu.g of recombinant human IL-8 (produced as a fusion of (ser-IL-8).sub.72 with ubiquitin (Hebert et al., J. Immunology 145:3033-3040 (1990)); IL-8 is available commercially from PeproTech, Inc., Rocky Hill, N.J.) resuspended in MPL/TDM (Ribi Immunochem. Research Inc., Hamilton, Mont.) and boosted twice with the same amount of IL-8. In these experiments, "IL-8" is intended to mean (ser-IL-8).sub.72 unless otherwise specified. A final boost of 10 .mu.g of IL-8 was given 3 days before the fusion. Spleen cells or popliteal lymph node cells were fused with mouse myeloma P3X63Ag8U.1 (ATCC CRL1597), a non-secreting clone of the myeloma P3X63Ag8, using 35% polyethylene glycol as described before. Ten days after the fusion, culture supernatant was screened for the presence of monoclonal antibodies to IL-8 by ELISA.

The ELISA was performed as follows. Nunc 96-well immunoplates (Flow Lab, McLean, Va.) were coated with 50 .mu.l/well of 2 .mu.g/ml IL-8 in phosphate-buffered saline (PBS) overnight at 4.degree. C. The remaining steps were carried out at room temperature. Nonspecific binding sites were blocked with 0.5% bovine serum albumin (BSA) for 1 hour (hr). Plates were then incubated with 50 .mu.l/well of hybridoma culture supernatants from 672 growing parental fusion wells for 1 hr, followed by the incubation with 50 .mu.l/well of 1:1000 dilution of a 1 mg/ml stock solution of alkaline phosphatase-conjugated goat anti-mouse Ig (Tago Co., Foster City, Calif.) for 1 hr. The level of enzyme-linked antibody bound to the plate was determined by the addition of 100 .mu.l/well of 0.5 mg/ml of r-nitrophenyl phosphate in sodium bicarbonate buffer, pH 9.6. The color reaction was measured at 405 nm with an ELISA plate reader (Titertrek Multiscan, Flow Lab, McLean, Va.). Between each step, plates were washed three times in PBS containing 0.05% Tween 20.

Culture supernatants which promoted 4-fold more binding of IL-8 than did control medium were selected as positives. According to this criterion, 16 of 672 growing parental fusion wells (2%) were positive. These positive hybridoma cell lines were cloned at least twice by using the limiting dilution technique.

Seven of the positive hybridomas were further characterized as follows. The isotypes of the monoclonal antibodies were determined by coating Nunc 96-well immunoplates (Flow Lab, McLean, Va.) with IL-8 overnight, blocking with BSA, incubating with culture supernatants followed by the addition of predetermined amount of isotype-specific alkaline phosphatase-conjugated goat anti-mouse Ig (Fisher Biotech, Pittsburgh, Pa.). The level of conjugated antibodies bound to the plate was determined by the addition of r-nitrophenyl phosphate as described above.

All the monoclonal antibodies tested belonged to either IgG.sub.1 or IgG.sub.2 immunoglobulin isotype. Ascites fluid containing these monoclonal antibodies had antibody titers in the range of 10,000 to 100,000 as determined by the reciprocal of the dilution factor which gave 50% of the maximum binding in the ELISA.

To assess whether these monoclonal antibodies bound to the same epitopes, a competitive binding ELISA was performed. At a ratio of biotinylated mAb to unlabeled mAb of 1:100, the binding of biotinylated mAb 5.12.14 was significantly inhibited by its homologous mAb but not by mAb 4.1.3, while the binding of biotinylated mAb 4.1.3 was inhibited by mAb 4.1.3 but not by mAb 5.12.14. Monoclonal antibody 5.2.3 behaved similarly to mAb 4.1.3, while monoclonal antibodies 4.8 and 12.3.9 were similar to mAb 5.12.14. Thus, mAb 4.1.3 and mAb 5.2.3 bind to a different epitope(s) than the epitope recognized by monoclonal antibodies 12.3.9, 4.8 and 5.12.14.

Immunodot blot analysis was performed to assess antibody reactivity to IL-8 immobilized on nitrocellulose paper. All seven antibodies recognized IL-8 immobilized on paper, whereas a control mouse IgG antibody did not.

The ability of these monoclonal antibodies to capture soluble .sup.125 I-IL-8 was assessed by a radioimmune precipitation test (RIP). Briefly, tracer .sup.125 I-IL-8 (4.times.10.sup.4 cpm) was incubated with various dilutions of the monoclonal anti-IL-8 antibodies in 0.2 ml of PBS containing 0.5% BSA and 0.05% Tween 20 (assay buffer) for 1 hr at room temperature. One hundred microliters of a predetermined concentration of goat anti-mouse Ig antisera (Pel-Freez, Rogers, Ariz.) were added and the mixture was incubated at room temperature for 1 hr. Immune complexes were precipitated by the addition of 0.5 ml of 6% polyethylene glycol (M.W. 8000) kept at 4.degree. C. After centrifugation at 2,000.times.g for 20 min at 4.degree. C., the supernatant was removed by aspiration and the radioactivity remaining in the pellet was counted in a gamma counter. Percent specific binding was calculated as (precipitated cpm-background cpm)/(total cpm-background cpm). Monoclonal antibodies 4.1.3, 5.2.3, 4.8, 5.12.14 and 12.3.9 captured .sup.125 I-IL-8 very efficiently, while antibodies 9.2.4 and 8.9.1 were not able to capture soluble .sup.125 I-IL-8 in the RIP even though they could bind to IL-8 coated onto ELISA plates (Table I).

The dissociation constants of these monoclonal antibodies were determined using a competitive binding RIP assay. Briefly, competitive inhibition of the binding each antibody to .sup.125 I-IL-8 (20,000-40,000 cpm per assay ) by various amounts of unlabeled IL-8 was determined by the RIP described above. The dissociation constant (affinity)of each mAb was determined by using Scatchard plot analysis (Munson, et al., Anal. Biochem. 107:220 (1980)) as provided in the VersaTerm-PRO computer program (Synergy Software, Reading, Pa.). The K.sub.d 's of these monoclonal antibodies (with the exception of 9.2.4. and 8.9.1) were in the range from 2.times.10.sup.-8 to 3.times.10.sup.-10 M. Monoclonal antibody 5.12.14 with a K.sub.d of 3.times.10.sup.-10 M showed the highest affinity among all the monoclonal antibodies tested (Table I).

To assess the ability of these monoclonal antibodies to neutralize IL-8 activity, the amount of .sup.125 I-IL-8 bound to human neutrophils in the presence of various amounts of culture supernatants and purified monoclonal antibodies was measured. Neutrophils were prepared by using Mono-Poly Resolving Medium (M-PRM) (Flow Lab. Inc., McLean, VA). Briefly fresh, heparinized human blood was loaded onto M-PRM at a ratio of blood to medium, 3.5:3.0, and centrifuged at 300.times.g for 30 min at room temperature. Neutrophils enriched at the middle layer were collected and washed once in PBS. Such a preparation routinely contained greater than 95% neutrophils according to the Wright's Giemsa staining. The receptor binding assay was done as follows. 50 .mu.l of .sup.125 I-IL-8 (5 ng/ml) was incubated with 50 .mu.l of unlabeled IL-8 (100 .mu.g/ml) or monoclonal antibodies in PBS containing 0.1% BSA for 30 min at room temperature. The mixture was then incubated with 100 .mu.l of neutrophils (10.sup.7 cells/ml) for 15 min at 37.degree. C. The .sup.125 I-IL-8 bound was separated from the unbound material by loading mixtures onto 0.4 ml of PBS containing 20% sucrose and 0.1% BSA and by centrifugation at 300.times.g for 15 min. The supernatant was removed by aspiration and the radioactivity associated with the pellet was counted in a gamma counter.

Monoclonal antibodies 4.1.3, 5.2.3, 4.8, 5.12.14, and 12.3.9 inhibited greater than 85% of the binding of IL-8 to human neutrophils at a 1:25 molar ratio of IL-8 to mAb. On the other hand, monoclonal antibodies 9.2.4 and 8.9.1 appeared to enhance the binding of IL-8 to its receptors on human neutrophils. Since a control mouse IgG also enhanced the binding of IL-8 on neutrophils, the enhancement of IL-8 binding to its receptors by mAb 9.2.4 and 8.9.1 appears to be nonspecific. Thus, monoclonal antibodies, 4.1.3, 5.1.3, 4.8, 5.12.14, and 12.3.9 are potential neutralizing monoclonal antibodies while monoclonal antibodies 8.9.1 and 9.2.4 are non-neutralizing monoclonal antibodies.

The ability of the anti-IL-8 antibodies to block neutrophil chemotaxis induced by IL-8 was tested as follows. Neutrophil chemotaxis induced by IL-8 was determined using a Boyden chamber method (Larsen, et al., Science 243:1464 (1989)). One hundred .mu.l of human neutrophils (10.sup.6 cells/ml) resuspended in RPMI containing 0.1% BSA were placed in the upper chamber and 29 .mu.l of the IL-8 (20 nM) with or without monoclonal antibodies were placed in the lower chamber. Cells were incubated for 1 hr at 37.degree. C. Neutrophils migrated into the lower chamber were stained with Wright's Giemsa stain and counted under the microscope (100.times.magnification). Approximately 10 different fields per experimental group were examined. Neutralizing monoclonal antibodies 5.12.14 and 4.1.3 blocked almost 70% of the neutrophil chemotactic activity of IL-8 at 1:10 ratio of IL-8 to mAb.

The isoelectric focusing (IEF) pattern of each mAb was determined by applying purified antibodies on an IEF polyacrylamide gel (pH 3-9, Pharmacia) using the Fast gel system (Pharmacia, Piscataway, N.J.). The IEF gel was pretreated with pharmalyte containing 1% Triton X100 (Sigma, St. Louis, Mo.) for 10 min before loading the samples. The IEF pattern was visualized by silver staining according to the instructions from the manufacturer. All of the monoclonal antibodies had different IEF patterns, confirming that they originated from different clones. The pI values for the antibodies are listed in Table I.

All these monoclonal antibodies bound equally well to both (ala-IL-8) 77 and (ser-IL-8)72 forms of IL-8. Because IL-8 has greater than 30% sequence homology with certain other members of the platelet factor 4 (PF4) family of inflammatory cytokines such as .beta.-TG (Van Damme et al., Eur. J. Biochem. 181:337(1989); Tanaka et al., FEB 236(2):467 (1988)) and PF4 (Deuel et al., Proc. Natl. Acad. Sci. U.S.A. 74:2256 (1977)), they were tested for possible cross reactivity to .beta.-TG and PF4, as well as to another neutrophil activating factor, C5a. No detectable binding to any of these proteins was observed, with the exception of mAb 4.1.3, which had a slight cross reactivity to .beta.-TG.

One of the antibodies, mAb 5.12.14, was further studied to determine whether it could block the IL-8 mediated release of elastase by neutrophils. Briefly, human neutrophils were resuspended in Hanks balanced salt solution (Gibco, Grand Island, N.Y.) containing 1.0% BSA, Fraction V (Sigma, St. Louis, Mo.), 2 mg/ml alpha-D-glucose (Sigma), 4.2 mM sodium bicarbonate (Sigma) and 0.01 M HEPES, pH 7.1 (JRH Bioscience, Lenexa, Kans.). A stock of cytochalasin B (Sigma) was prepared (5 mg/ml in dimethylsulfoxide (Sigma) and stored at 2.degree.-8.degree. C. Cytochalasin B was added to the neutrophil preparation to produce a final concentration of 5 .mu.g/ml, and incubated for 15 min at 37.degree. C. Human IL-8 was incubated with mAb 5.12.14 (20 .mu.l), or a negative control antibody, in 1 ml polypropylene tubes (DBM Scientific, San Fernando, Calif.) for 30 min at 37.degree. C. The final assay concentrations of IL-8 were 50 and 500 nM. The monoclonal antibodies were diluted to produce the following ratios (IL-8:Mab): 1:50, 1:10, 1:2, 1:1, and 1:0.25. Cytochalasin B-treated neutrophils were added (100 .mu.l/tube) and incubated for 2 hours at 25.degree. C. The tubes were centrifuged (210.times.g, 2 -8.degree. C.) for 10 min, and supernatants were transferred to 96 well tissue culture plates (30 .mu.l/well). Elastase substrate stock, 10 mM methoxysuccinyl-alanyl-alanyl-propyl-valyl-p-nitroanilide (Calbiochem, La Jolla, Calif.) in DMSO was prepared and stored at 2.degree.-8.degree. C. Elastase substrate solution (1.2 mM substrate, 1.2M NaCl (Mallinckrodt, Paris, Kentucky), 0.12M HEPES pH 7.2 in distilled water) was added (170 .mu.l/well) to the supernatants and incubated for 0.5 to 2 hours at 37.degree. C. (until control O.D. of 1.0 was reached). Absorbance was measured at 405 nm (SLT 340 ATTC plate reader, SLT Lab Instruments, Austria).

The results are shown in FIG. 1. At a 1:1 ratio of IL-8 to mAb 5.12.14, the antibody was able to effectively block the release of elastase from neutrophils.

The hybridoma producing antibody 5.12.14 was deposited on Feb. 15, 1993 with the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md., U.S.A. (ATCC) and assigned ATTC Accession No. HB 11553. This deposit was made under the provisions of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purpose of Pat. Procedure and the Regulations thereunder (Budapest Treaty).

Antibodies against rabbit IL-8 were generated in essentially the same process as anti-human IL-8 antibodies using rabbit IL-8 as immunogen (kindly provided by C. Broaddus; see also Yoshimura et al., J. Immunol. 146:3483 (1991)). The antibody was characterized as described above for binding to other cytokines coated onto ELISA plates; no measurable binding was found to MGSA, fMLP, C5a, b-TG, TNF, PF4, or IL-1.

The hybridoma producing antibody 6G4.2.5 was deposited on Sep. 28, 1994, with the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md., U.S.A. (ATCC) and assigned ATTC Accession No. HB 11722. This deposit was made under the provisions of the Budapest Treaty on the international Recognition of the Deposit of Microorganisms for the Purpose of Patent Procedure and the Regulations thereunder (Budapest Treaty).

Recombinant human-murine chimeric Fabs for 5.12.14 and 6G.sub.4.2.5 were constructed as described below. A chimeric 6G.4.25 Fab is compared with a chimeric 5.12.14 Fab in detail below.

1. Inhibition of IL-8 binding to Human Neutrophils by 5.12.14-FAB and 6G4 2.5-FAB

The ability of the two chimeric Fabs, 5.12.14-Fab and 6G4.2.5-Fab, to efficiently bind IL-8 and prevent IL-8 from binding to IL-8 receptors on human neutrophils was determined by performing a competition binding assay which allows the calculation of the IC.sub.50 -concentration required to achieve 50% inhibition of IL-8 binding.

Human neutrophils (5.times.10.sup.5) were incubated for 1 hour at 4.degree. C. with 0.5 nM .sup.125 I-IL-8 in the presence of various concentrations (0 to 300 nM) of 5.12.14-Fab, 6G4.2.5-Fab, an isotype control (4D5-Fab) or unlabeled IL-8. After the incubation, the unbound .sup.125 I-IL-8 was removed by centrifugation through a solution of 20% sucrose and 0.1% bovine serum albumin in phosphate buffered saline and the amount of .sup.125 I-IL-8 bound to the cells was determined by counting the cell pellets in a gamma counter. FIG. 2 demonstrates the inhibition of .sup.125 I-IL-8 binding to neutrophils by unlabeled IL-8. FIG. 3 demonstrates that a negative isotype matched Fab does not inhibit the binding of .sup.125 I-IL-8 to human neutrophils. Both the anti-IL-8 Fabs, 5.12.14 Fab (FIG. 4) and 6G.4.25 Fab (FIG. 5) were able to inhibit the binding of .sup.125 I-IL-8 to human neutrophils with an average IC.sub.50 of 1.6 nM and 7.5 nM, respectively.

2. Inhibition of IL-8-Mediated Neutrophil Chemotaxis by 5.12.14-Fab and 6G4.2.5-Fab

Human neutrophils were isolated, counted and resuspended at 5.times.10.sup.6 cells/ml in Hank's balanced salt solution (abbreviated HBSS; without calcium and magnesium) with 0.1% bovine serum albumin. The neutrophils were labeled by adding calcein AM (Molecular Probe, Eugene, Oreg.) at a final concentration of 2.0 .mu.M. Following a 30 minute incubation at 37.degree. C., cells were washed twice with HBSS-BSA and resuspended at 5.times.10.sup.6 cells/ml.

Chemotaxis experiments were carried out in a Neuro Probe (Cabin John, MD) 96-well chamber, model MBB96. Experimental samples (buffer only control, IL-8 alone or IL-8+Fabs) were loaded in a Polyfiltronics 96-well View plate (Neuro Probe inc.) placed in the lower chamber. 100 .mu.l of the calcein AM-labeled neutrophils were added to the upper chambers and allowed to migrate through a 5 micrometer porosity PVP free polycarbonate framed filter (Neuro Probe Inc.) toward the bottom chamber sample. The chemotaxis apparatus was then incubated for 40 to 60 minutes at 37.degree. C. with 5% CO.sub.2. At the end of the incubation, neutrophils remaining in the upper chamber were aspirated and upper chambers were washed three times with PBS. Then the polycarbonate filter was removed, non-migrating cells were wiped off with a sgueegee wetted with PBS, and the filter was air dried for 15 minutes.

The relative number of neutrophils migrating through the filter (Neutrophil migration index) was determined by measuring fluorescence intensity of the filter and the fluorescence intensity of the contents of the lower chamber and adding the two values together. Fluorescence intensity was measured with a CytoFluor 2300 fluorescent plate reader (Millipore Corp. Bedford, Mass.) configured to read a Corning 96-well plate using the 485-20 run excitation filter and a 530-25 emission filter, with the sensitivity set at 3.

The results are shown in FIGS. 6 and 7. FIG. 6 demonstrates the inhibition of human IL-8 mediated neutrophil chemotaxis by chimeric 6G4.2.5 and 5.12.14 Fabs. FIG. 7 demonstrates the relative abilities of chimeric 6G4.2.5 and 5.12.14 Fabs to inhibit rabbit IL-8 mediated neutrophil chemotaxis.

3. Inhibition of IL-8-Mediated Neutrophil Elastase Release by Various Concentrations of 6G4.2.5 and 5.12.14 Fabs

Blood was drawn from healthy male donors into heparinized syringes. Neutrophils were isolated by dextran sedimentation, centrifugation over Lymphocyte Separation Medium (Organon Teknika, Durham, N.C.), and hypotonic lysis of contaminating red blood cells as described by Berman et al. (J. Cell Biochem. 52:183 (1993)). The final neutrophil pellet was suspended at a concentration of 1.times.10.sup.7 cells/ml in assay buffer, which consisted of Hanks Balanced Salt Solution (GIBCO, Grand Island, N.Y.) supplemented with 1.0% BSA (fraction V, Sigma, St. Louis, Mo.), 2 mg/ml glucose, 4.2 mM sodium bicarbonate, and 0.01M HEPES, pH 7.2. The neutrophils were stored at 4.degree. C. for not longer than 1 hr.

IL-8 (10 .mu.l) was mixed with anti-IL-8 Fab, an isotype control Fab, or buffer (20 .mu.l) in 1 ml polypropylene tubes and incubated in a 37.degree. C. water bath for 30 min. IL-8 was used at final concentrations ranging from 0.01 to 1000 nM in dose response studies (FIG. 8) and at a final concentration of 100 nM in the experiments addressing the effects of the Fabs on elastase release (FIGS. 9 and 10). Fab concentrations ranged from approximately 20 nM to 300 nM, resulting in Fab:IL-8 molar ratios of 0.2:1 to 3:1. Cytochalasin B (Sigma) was added to the neutrophil suspension at a concentration of 5 .mu.g/ml (using a 5 mg/ml stock solution made up in DMSO), and the cells were incubated for 15 min in a 37.degree.C. water bath. Cytochalasin B-treated neutrophils (100 .mu.l) were then added to the IL-8/Fab mixtures. After a 3 hr incubation at room temperature, the neutrophils were pelleted by centrifugation (200.times.g for 5 min), and aliquots of the cell-free supernatants were transferred to 96 well plates (30 .mu.l/well). The elastase substrate, methoxysuccinyl-alanyl-alanyl-prolyl-valyl-p-nitroanilide (Calbiochem, La Jolla, Calif.), was prepared as a 10 mM stock solution in DMSO and stored at 4.degree. C. Elastase substrate working solution was prepared just prior to use (1.2 mM elastase substrate, 1M NaCl, 0.12M HEPES, pH 7.2), and 170 .mu.l was added to each sample-containing well. The plates were placed in a 37.degree. C. tissue culture incubator for 30 min or until an optical density reading for the positive controls reached at least 1.0. Absorbance was measured at 405 run using an SLT 340 plate reader (SLT Lab Instruments, Austria).

FIG. 9 demonstrates the ability of the chimeric anti-IL-8 Fabs to inhibit elastase release from human neutrophils stimulated by human IL-8; FIG. 10 demonstrates the relative abilities of the chimeric anti-IL-8 Fabs to inhibit elastase release from human neutrophils stimulated by rabbit IL-8.

One of the most widely accepted models of chronic experimental colitis is 2,4,6-trinitrobenezenesulfonic acid (TNBS)-induced injury, recently described by Morris et al., Gastroenterology 1 96:795 (1989). Briefly, rectal administration of 10 to 30 mg of TNBS in 0.25 ml of 50% ethanol produces acute and chronic local inflammation documented by dose-dependent increases in colonic weights, gross ulceration, and myeloperoxidase values. High doses of TNBS (30 mg) in ethanol produces colonic injury that peaks at 1 week but persists for at least 8 weeks after administration. Colonic inflammation is accompanied by weight loss in the first week, diarrhea in 90% of animals during weeks 1 to 3, and stenosis of the distal colon with proximal dilation, but only 3% mortality. In chronic phases, inflammation is segmenental with linear (transverse) ulcers and marked thickening of the colon. Transmural acute and chronic inflammation is noted histologically with a progressive increase in inflammatory cell infiltration in the external muscle and serosa during weeks 3 to 5. Mucosal and serosal granulomas are present in 55% of animals examined at 2 to 3 weeks and in approximately 20% of animals 4 weeks or more after injury.

To study the ability of the anti-IL-8 antibodies of the invention to attenuate acute colitis in rabbits, colitis was induced in New Zealand White rabbits (1.8-2 kg body wt) by intracolonic instillation of 5 ml of 17-35 mg/ml Trinitrobenzene sulfonic acid in 30% ethanol (TNBS/EtOH) (adapted from the method of Morris et al., Gastroenterology 1 96:795 (1989)). Five rabbits were treated intravenously with 5 mg/kg 6G4.2.5. Three control rabbits received PBS. Animals treated with TNBS/EtOH were euthanized after 24 hours post dosing and the colon tissue was examined for levels of IL-8, myeloperoxidase (enzyme marker for polymorphonuclear leukocytes or heterophils), wet colon weight, gross inflammation, and histopathology. Two sections of colon were preserved in formalin, processed by standard procedures for routine hematoxylin and eosin sections. The colon tissue was examined for levels of IL-8 by enzyme linked immunoassay. Wet colon weight from treated and untreated rabbits was measured and compared. Edema was measured as the thickness of the submucosa in 3 to 5 sites per sample. Leukocytic margination was evaluated by determining which vessels in the tissue section were affected (e.g., superficial, involving only the subepithelial vessels in the lamina propria, to marked, involving vessels in the submucosa). The extent of necrosis was measured as the percent of the colon manifesting necrosis. The severity of necrosis was measured as the depth of penetration of necrosis into the wall of the colon. Gross inflammation was defined as the severity of inflammation over the length of the involved colon and was scored visually based upon the degree of swelling and coloration. Leukocytic infiltration was determined by counting the number of neutrophils per high power field (HPF) (40X magnification). Mononuclear cell infiltration was determined by counting the number of mononuclear cells per HPF (40X magnification).

Heterophil (neutrophil) influx into inflamed rabbit colonic tissue was monitored by measurement of MPO levels (see, for example, Bradley et al., J. Invest. Dermatol. 7B:206 (1982)). Briefly, colonic sections were placed in 15 ml polypropylene tubes and incubated at 60.degree. C. for 2 hours. The tissues were frozen in liquid nitrogen. Fine powder tissue lysates were prepared with a mortar and pestle and transferred into 15 ml polypropylene tubes. The tissue samples were solubilized in 0.5% hexadecyl trimethyl ammonium (HTAB) (0.5% w/v in 50 mM KPO.sub.4 buffer at pH6) at a ratio of 3.5 ml per gram of tissue using a tissue homogenizer. The samples were frozen and thawed twice by freezing in liquid nitrogen and thawing in 60.degree. C. water bath. The samples were then sonicated for 10 seconds at a 50% duty cycle at 2.5 power level. Each sample lysate was transferred to an microfuge tube and centrifuged at room temperature for 15 minutes at 15,600.times.g. The samples were transferred to fresh clean Microfuge tubes. Seventy five .mu.l of each sample and 75 .mu.l of human MPO standard positive control (Calbiochem Corp., San Diego, Calif.) in HTAB diluted to 0.03 units per well were transferred in triplicate to a 96 well flat bottom plate. Seventy-five .mu.l of HTAB (0.5% w/v in 50 mM KPO4 buffer pH 6.0) were added as reference blanks. One hundred .mu.l of H.sub.2 O.sub.2 were added to each well. The reaction in the 96 well plate was monitored on a Thermo Max optical plate reader (Molecular Devices Co. Menlo Park, Calif.). A stock solution of O-dianisidine (Sigma, St. Louis, Mo.) at 10 mg dry powder in 1.0 ml of distilled H.sub.2 O was prepared and drawn through a 0.2 micron filter. Twenty-five .mu.l were added to each well. The plates were read at OD 450 nm continuously at 3-5 minute intervals over a 30 minute period.

Increased levels of myeloperoxidase and IL-8 were detected in animals dosed with increasing doses of TNBS/EtOH as compared to sham treated control animals. Increased colonic weight and gross inflammation were also evident. Histological evaluation revealed mucosal necrosis of the bowel wall, with heterophil margination of the blood vessels and infiltration in the affected tissue.

However, treatment of rabbits with anti-IL-8 antibodies reduced the severity of TNBS/EtOH-induced colitis. Lesions in animals treated with 5 mg/Kg intravenous 6G4.2.5, just prior to colitis induction with TNBS/EtOH, were attenuated in 4 of 5 animals as compared to 3 control animals. Antibody treatment reduced the extent and severity of necrosis, gross inflammation, colonic weight, edema, heterophil margination and infiltration. The levels of colonic myeloperoxidase and IL-8 were greatly reduced. The results of these experiments are depicted in FIG. 11A-11J. These observations support the usefulness of anti-IL-8 antibodies in the attenuation of colitis.

Neutrophils migrate into the lung in response to a variety of stimuli, including infection by Streptococcus pneumoniae. To determine whether the anti-IL-8 antibodies of the instant invention could inhibit such neutrophil migration, thereby ameliorating inflammation in the lung, a rabbit pneumonia model was used. Briefly, anesthetized New Zealand white rabbits were given intrabronchial instillations of Streptococcus pneumoniae, Escherichia coli, or Pseudomonas aeruginosa (3.times.10.sup.9 organisms/ml) combined with either anti-rabbit IL-8 antibody (clone 6G4.2.5) or control mouse IgG (final concentration 0.5 mg/ml) and colloidal carbon (5%) in a total volume of 0.5 ml. After 3 hours and 50 min, the rabbits received an intravenous injection of radiolabeled microspheres to measure pulmonary blood flow. At 4 hours, the heart and lungs were removed and the lungs were separated. The pneumonic region (usually the left lower lobe) as indicated by the colloidal carbon and the corresponding region in the contralateral lung was lavaged using phosphate-buffered saline. Total leukocyte counts were obtained using a hemacytometer on the lavage fluid and differential counts were performed on Wright-stained cytospin preparations.

Treatment with anti-rabbit IL-8 antibodies significantly reduced the number of neutrophils present in the BAL fluid compared to animals treated with isotype control mouse igG (FIG. 12). Thus, anti-IL-8 antibodies effectively reduce neutrophil emigration in the pneumonic lung.

Total RNA was isolated from 1.times.10.sup.8 cells (hybridoma cell line ATCC HB-11722) using the procedure described by Chomczynski and Sacchi (Anal. Biochem. 162:156 (1987)). First strand cDNA was synthesized by specifically priming the mRNA with synthetic DNA oligonucleotides designed to hybridize with regions of the murine RNA encoding the constant region of the kappa light chain or the IgG2a heavy chain (the DNA sequence of these regions are published in Sequences of Proteins of Immunological Interest, Kabat, E. A. et al. (1991) NIH Publication 91-3242, V 1-3.). Three primers were designed for each of the light and heavy chains to increase the chances of primer hybridization and efficiency of first strand cDNA synthesis (FIG. 13). Amplification of the first strand cDNA to double-stranded (ds) DNA was accomplished using two sets of synthetic DNA oligonucleotide primers: one forward primer and one reverse primer for the light chain variable region amplification (FIG. 14) and one forward primer and one reverse primer for the heavy chain variable region amplification (FIG. 15). The N-terminal sequence of the first eight amino acids of either the light or heavy chains of 5.12.14 was used to generate a putative murine DNA sequence corresponding to this region. (A total of 29 amino acids was sequenced from the N-terminus of both the light chain and heavy chain variable regions using the Edman degradation protein sequencing technique.) This information was used to design the forward amplification primers which were made degenerate in the third position for some codons to increase the chances of primer hybridization to the natural murine DNA codons and also included the unique restriction site, MluI, for both the light chain variable region forward primer and the heavy chain variable region forward primer to facilitate ligation to the 3' end of the STII element in the cloning vector. The reverse amplification primers were designed to anneal with the murine DNA sequence corresponding to a portion of the constant region of the light or heavy chains near the variable/constant junction. The light chain variable region reverse primer contained a unique BstBi restriction site and the heavy chain variable region reverse primer contained a unique ApaI restriction site for ligation to the 540 end of either the human IgG1 constant light or IgG1 constant heavy regions in the vectors, pB13.1 (light chain) and pB14 (heavy chain). The polymerase chain reaction using these primer sets yielded DNA fragments of approximately 400 bp. The cDNA encoding the 5.12.14 light chain variable region was cloned into the vector pB13.1, to form pA51214VL and the 5.12.14 heavy chain variable region was cloned into the vector, pB14, to form pA51214VH. The cDNA inserts were characterized by DNA sequencing and are presented in FIG. 16 (murine light chain variable region) and FIG. 17 (murine heavy chain variable region).

In the initial construct, pA51214VL, the amino acids between the end of the 5.12.14 murine light chain variable sequence and the unique cloning site, BstBI, in the human IgG1 constant light sequence were of murine origin corresponding to the first 13 amino acids of the murine IgG1 constant region (FIG. 16). Therefore, this plasmid contained a superfluous portion of the murine constant region separating the 5.12.14 murine light chain variable region and the human light chain IgG1 constant region. This intervening sequence would alter the amino acid sequence of the chimera and most likely produce an incorrectly folded Fab. This problem was addressed by immediately truncating the cDNA clone after A109 and re-positioning the BstBI site to the variable/constant junction by the polymerase chain reaction. FIG. 18 shows the amplification primers used to make these modifications. The forward primer, VL.front, was designed to match the last five amino acids of the STII signal sequence, including the MluI cloning site, and the first 4 amino acids of the 5.12.14 murine light chain variable sequence. The sequence was altered from the original cDNA in the third position of the first two codons D1 (T to C) and I2 (C to T) to create a unique EcoRV cloning site which was used for later constructions. The reverse primer, VL.rear, was designed to match the first three amino acids of the human IgG1 constant light sequence and the last seven amino acids of the 5.12.14 light chain variable sequence which included a unique BstBI cloning site. In the process of adding the BstBI site, the nucleotide sequence encoding several amino acids were altered: L106 (TTG to CTT), K107 (AAA to CGA) resulting in a conservative amino acid substitution to arginine, and R108 (CGG to AGA). The PCR product encoding the modified 5.12.14 light chain variable sequence was then subcloned into pB13.1 in a two-part ligation. The MluI-BstBi digested 5.12.14 PCR product encoding the light chain variable region was ligated into MluI-BstBI digested vector to form the plasmid, pA51214VL'. The modified cDNA was characterized by DNA sequencing. The coding sequence for the 5.12.14 light chain is shown in FIG. 19.

Likewise, the DNA sequence between the end of the heavy chain variable region and the unique cloning site, ApaI, in the human igG1 heavy chain constant domain of pA51214VH was reconstructed to change the amino acids in this area from murine to human. This was done by the polymerase chain reaction. Amplification of the murine 5.12.14 heavy chain variable sequence was accomplished using the primers shown in FIG. 18. The forward PCR primer was designed to match nucleotides 867-887 in pA51214VH upstream of the STII signal sequence and the putative cDNA sequence encoding the heavy chain variable region and included the unique cloning site SpeI. The reverse PCR primer was designed to match the last four amino acids of the 5.12.14 heavy chain variable sequence and the first six amino acids corresponding to the human IgG1 heavy constant sequence which also included the unique cloning site, ApaI. The PCR product encoding the modified 5.12.14 heavy chain variable sequence was then subcloned to the expression plasmid, pMHM24.2.28 in a two-part ligation. The vector was digested with SpeI-ApaI and the SpeI-ApaI digested 5.12.14 PCR product encoding the heavy chain variable region was ligated into it to form the plasmid, pA51214VH'. The modified cDNA was characterized by DNA sequencing. The coding sequence for the 5.12.14 heavy chain is shown in FIGS. 20A-20B.

The first expression plasmid, pantiIL-8.1, encoding the chimeric Fab of 5.12.14 was made by digesting pA51214VH' with EcoRV and Bpu1102I to replace the EcoRV-Bpul1102I fragment with a EcoRV-Bpu1102I fragment encoding the murine 5.12.14 light chain variable region of pA51214VL'. The resultant plasmid thus contained the murine-human variable/constant regions of both the light and heavy chains of 5.12.14.

Preliminary analysis of Fab expression using pantiIL-8.1 showed that the light and heavy chains were produced intracellularly but very little was being secreted into the periplasmic space of E. coli. To correct this problem, a second expression plasmid was constructed.

The second expression plasmid, pantiIL-8.2, was constructed using the plasmid, pmy187, as the vector. Plasmid pantiIL-8.2 was made by digesting pmy187 with MluI and SphI and the MluI (partial)-SphI fragment encoding the murine 5.12.14 murine-human chimeric Fab of pantiIL-8.1 was ligated into it. The resultant plasmid thus contained the murine-human variable/constant regions of both the light and heavy chains of 5.12.14.

The plasmid pantiIL-8.2 was deposited on Feb. 10, 1995 with the American Type Culture Collection, 12301 Parklawn Drive, Rockville, MD, U.S.A. (ATCC) and assigned ATTC Accession No. ATCC 97056. This deposit was made under the provisions of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purpose of Pat. Procedure and the Regulations thereunder (Budapest Treaty).

Total RNA was isolated from 1.times.10.sup.8 cells (hybridoma cell line 6G4.2.5) using the procedure described by Chomczynski and Sacchi (Anal. Biochem. 162:156 (1987)). First strand cDNA was synthesized by specifically priming the mRNA with synthetic DNA oligonucleotides designed to hybridize with regions of the murine RNA encoding the constant region of the kappa light chain or the IgG2a heavy chain (the DNA sequence of these regions are published in Sequences of Proteins of Immunological Interest, Kabat et al. (1991) NIH Publication 91-3242, V 1-3). Three primers were designed for each the light and heavy chains to increase the chances of primer hybridization and efficiency of first strand cDNA synthesis (of the first strication of the first strand cDNA to double-stranded (ds) DNA was accomplished using two sets of synthetic DNA oligonucleotide primers: one forward primer and one reverse primer for the light chain variable region amplification (FIG. 22) and one forward primer and one reverse primer for the heavy chain variable region amplification (FIG. 23). The N-terminal sequence of the first eight amino acids of either the light or heavy chains of 6G.sub.4.2.5 was used to generate a putative murine DNA sequence corresponding to this region. (A total of 29 amino acids were sequenced from the N-terminus of both the light chain and heavy chain variable regions using the Edman degradation protein sequencing technique.) This information was used to design the forward amplification primers which were made degenerate in the third position for some codons to increase the chances of primer hybridization to the natural murine DNA codons and also included the unique restriction site, NsiI, for the light chain variable region forward primer and the unique restriction site, MluI, for the heavy chain variable region forward primer to facilitate ligation to the 3' end of the STII element in the vector, pchimFab. The reverse amplification primers were designed to anneal with the murine DNA sequence corresponding to a portion of the constant region of the light or heavy chains near the variable/constant junction. The light chain variable region reverse primer contained a unique MunI restriction site and the heavy chain variable region reverse primer contained a unique ApaI restriction site for ligation to the 5' end of either the human IgG1 constant light or IgG1 constant heavy regions in the vector, pchimFab. The polymerase chain reaction using these primer sets yielded DNA fragments of approximately 400 bp and were cloned individually into the vector, pchimFab, to form p6G425VL and p6G425VH. The cDNA inserts were characterized by DNA sequencing and are presented in FIG. 24 (murine light chain variable region) and FIG. 25 (murine heavy chain variable region).

In the initial construct, p6G425VL, the amino acids between the end of the 6G4.2.5 murine light chain variable sequence and the unique cloning site, MunI, in the human IgG1 constant light sequence were of murine origin. These amino acids must match the human IgG1 amino acid sequence to allow proper folding of the chimeric Fab. Two murine amino acids, D115 and S121, differed dramatically from the amino acids found in the loops of the .beta.-strands of the human IgG1 constant domain and were converted to the proper human amino acid residues, V115 and F121, by site-directed mutagenesis using the primers shown in FIG. 26. These specific mutations were confirmed by DNA sequencing and the modified plasmid named p6G425VL'. The coding sequence is shown in FIGS. 27A-27B.

Likewise, the DNA sequence between the end of the heavy chain variable region and the unique cloning site, ApaI, in the human IgG1 heavy chain constant domain of p6G425VH was reconstructed to change the amino acids in this area from murine to human. This process was facilitated by the discovery of a BstEII site near the end of the heavy chain variable region. This site and the ApaI site were used for the addition of a synthetic piece of DNA encoding the corresponding IgG human amino acid sequence. The synthetic oligonucleotides shown in FIG. 26 were designed as complements of one another to allow the formation of a 27 bp piece of ds DNA. The construction was performed as a three-part ligation because the plasmid, p6G425VH, contained an additional BstEII site within the vector sequence. A 5309 bp fragment of p6G425VH digested with MluI-ApaI was ligated to a 388 bp fragment carrying the 6G4.2.5 heavy chain variable region and a 27 bp synthetic DNA fragment encoding the first six amino acids of the human IgG1 constant region to form the plasmid, p6G425VH'. The insertion of the synthetic piece of DNA was confirmed by DNA sequencing. The coding sequence is shown in FIGS. 28A-28B.

The expression plasmid, p6G425chim2, encoding the chimeric Fab of 6G4.2.5 was made by digesting p6G425chimVL' with MluI and ApaI to remove the STII-murine HPC4 heavy chain variable region and replacing it with the MluI-ApaI fragment encoding the STII-murine 6G4.2.5 heavy chain variable region of p6G425chimVH'. The resultant plasmid thus contained the murine-human variable/constant regions of both the light and heavy chains of 6G4.2.5.

The plasmid p6G425chim2 was deposited on Feb. 10, 1995 with the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md., U.S.A. (ATCC) and assigned ATTC Accession No. ATCC 97055. This deposit was made under the provisions of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purpose of Pat. Procedure and the Regulations thereunder (Budapest Treaty).