US 5,627,153 AGrant

Anti-Fungal Methods and Materials

Issue Date:1997-05-06

•16 Claims

•8 Drawing Sheets

Abstract

The present invention relates to methods for treating fungal infection comprising administering to a subject suffering from a fungal infection a bactericidal/permeability-inducing (BPI) protein product.

Metadata

Assignee

Xoma Corporation

Inventors

Roger G. Little, II
Edward Lim
Patrick J. Scannon
Lewis J. Lambert, Jr.

Application Information

Application Number:US 3721051

Filing Date:1995-01-13

Priority Date:1994-01-14

Art Unit:181

Classifications

IPC:

A61K 3800C07K 100

Field of Search:

51453012;21350;324;380

Patent Drawings (8 sheets)

Description

Background of the Invention

The present invention relates generally to methods of treating fungal infections by administration of bactericidal/permeability-increasing (BPI) protein products.

BPI is a protein isolated from the granules of mammalian polymorphonuclear leukocytes (PMNs or neutrophils), which are blood cells essential in the defense against invading microorganisms. Human BPI protein has been isolated from PMNs by acid extraction combined with either ion exchange chromatography [Elsbach, J. Biol. Chem., 254:11000 (1979)] or E. coil affinity chromatography [Weiss, et al., Blood, 69:652 (1987)]. BPI obtained in such a manner is referred to herein as natural BPI and has been shown to have potent bactericidal activity against a broad spectrum of gram-negative bacteria. The molecular weight of human BPI is approximately 55,000 daltons (55 kD). The amino acid sequence of the entire human BPI protein and the nucleic acid sequence of DNA encoding the protein have been reported in FIG. 1 of Gray et al., J. Biol. Chem., 264:9505 (1989), incorporated herein by reference. The Gray et al. amino acid sequence is set out in SEQ ID NO: 69 hereto.

BPI is a strongly cationic protein. The N-terminal haft of BPI accounts for the high net positive charge; the C-terminal half of the molecule has a net charge of -3. [Elsbach and Weiss (1981), supra.] A proteolytic N-terminal fragment of BPI having a molecular weight of about 25 kD has an amphipathic character, containing alternating hydrophobic and hydrophilic regions. This N-terminal fragment of human BPI possesses the anti-bacterial efficacy of the naturally-derived 55 kD human BPI holoprotein. [Ooi et al., J. Bio. Chem., 262: 14891-14894 (1987)]. In contrast to the N-terminal portion, the C-terminal region of the isolated human BPI protein displays only slightly detectable anti-bacterial activity against gram-negative organisms. [Ooi et at., J. Exp. Med., 174:649 (1991).] An N-terminal BPI fragment of approximately 23 kD, referred to as "rBPI.sub.23," has been produced by recombinant means and also retains anti-bacterial activity against gram-negative organisms. Gazzano-Santoro et at., Infect. Immun. 60:4754-4761 (1992).

The bactericidal effect of BPI has been reported to be highly specific to gram-negative species, e.g., in Elsbach and Weiss, Inflammation. Basic Principles and Clinical Correlates, eds. Gallin et at., Chapter 30, Raven Press, Ltd. (1992). BPI is commonly thought to be non-toxic for other microorganisms, including yeast, and for higher eukaryotic cells. Elsbach and Weiss (1992), supra, reported that BPI exhibits anti-bacterial activity towards a broad range of gram-negative bacteria at concentrations as low as 10.sup.-8 to 10.sup.-9 M, but that 100- to 1,000-fold higher concentrations of BPI were non-toxic to all of the gram-positive bacterial species, yeasts, and higher eukaryotic cells tested at that time. It was also reported that BPI at a concentration of 10.sup.6 M or 160 .mu.g/ml had no toxic effect, when tested at a pH of either 7.0 or 5.5, on the gram-positive organisms Staphylococcus aureus (four strains), Staphylococcus epidermidis, Streptococcus faecalis, Bacillus subtilis, Micrococcus lysodeikticus, and Listeria monocytogenes. BPI at 10.sup.-6 M reportedly had no toxic effect on the fungi Candida albicans and Candida parapsilosis at pH 7.0 or 5.5, and was non-toxic to higher eukaryotic cells such as human, rabbit and sheep red blood cells and several human tumor cell lines. See also Elsbach and Weiss, Advances in Inflammation Research, ed. G. Weissmann, Vol. 2, pages 95-113 Raven Press (1981). This reported target cell specificity was believed to be the result of the strong attraction of BPI for lipopolysaccharide (LPS), which is unique to the outer membrane (or envelope) of gram-negative organisms.

The precise mechanism by which BPI kills gram-negative bacteria is not yet completely elucidated, but it is believed that BPI must first bind to the surface of the bacteria through electrostatic and hydrophobic interactions between the cationic BPI protein and negatively charged sites on LPS. LPS has been referred to as "endotoxin" because of the potent inflammatory response that it stimulates, i.e., the release of mediators by host inflammatory cells which may ultimately result in irreversible endotoxic shock. BPI binds to lipid A, reported to be the most toxic and most biologically active component of LPS.

In susceptible gram-negative bacteria, BPI binding is thought to disrupt LPS structure, leading to activation of bacterial enzymes that degrade phospholipids and peptidoglycans, altering the permeability of the cell's outer membrane, and initiating events that ultimately lead to cell death. [Elsbach and Weiss (1992), supra]. BPI is thought to act in two stages. The first is a sublethal stage that is characterized by immediate growth arrest, permeabilization of the outer membrane and selective activation of bacterial enzymes that hydrolyze phospholipids and peptidoglycans. Bacteria at this stage can be rescued by growth in serum albumin supplemented media [Mannion et at., J. Clin. Invest., 85:853-860 (1990)]. The second stage, defined by growth inhibition that cannot be reversed by serum albumin, occurs after prolonged exposure of the bacteria to BPI and is characterized by extensive physiologic and structural changes, including apparent damage to the inner cytoplasmic membrane.

Initial binding of BPI to LPS leads to organizational changes that probably result from binding to the anionic groups in the KDO region of LPS, which normally stabilize the outer membrane through binding of Mg.sup.++ and Ca.sup.++. Attachment of BPI to the outer membrane of gram-negative bacteria produces rapid permeabilization of the outer membrane to hydrophobic agents such as actinnomycin D. Binding of BPI and subsequent gram-negative bacterial killing depends, at least in part, upon the LPS polysaccharide chain length, with long O-chain bearing, "smooth" organisms being more resistant to BPI bactericidal effects than short O-chain beating, "rough" organisms [Weiss et at., J. Clin. Invest. 65:619-628 (1980)]. This first stage of BPI action, permeabilization of the gram-negative outer envelope, is reversible upon dissociation of the BPI, a process requiring the presence of divalent cations and synthesis of new LPS [Weiss et at., J. Immunol. 132:3109-3115 (1984)]. Loss of gram-negative bacterial viability, however, is not reversed by processes which restore the envelope integrity, suggesting that the bactericidal action is mediated by additional lesions induced in the target organism and which may be situated at the cytoplasmic membrane (Mannion et at., J. Clin. Invest. 86:631-641 (1990)). Specific investigation of this possibility has shown that on a molar basis BPI is at least as inhibitory of cytoplasmic membrane vesicle function as polymyxin B (In't Veld et at., Infection and Immunity 56:1203-1208 (1988)) but the exact mechanism as well as the relevance of such vesicles to studies of intact organisms has not yet been elucidated.

Fungi are eukaryotic cells that may reproduce sexually or asexually and may be biphasic, with one form in nature and a different form in the infected host. Fungal diseases are referred to as mycoses. Some mycoses are endemic, i.e. infection is acquired in the geographic area that is the natural habitat of that fungus. These endemic mycoses are usually self-limited and minimally symptomatic. Some mycoses are chiefly opportunistic, occurring in immunocompromised patients such as organ transplant patients, cancer patients undergoing chemotherapy, burn patients, AIDS patients, or patients with diabetic ketoacidosis.

Fungal infections are becoming a major health concern for a number of reasons, including the limited number of anti-fungal agents available, the increasing incidence of species resistant to older anti-fungal agents, and the growing population of immunocompromised patients at risk for opportunistic fungal infections. The incidence of systemic fungal infections increased 600% in teaching hospitals and 220% in non-teaching hospitals during the 1980's. The most common clinical isolate is Candida albicans (comprising about 19% of all isolates). In one study, nearly 40% of all deaths from hospital-acquired infections were due to fungi. [Sternberg, Science, 266:1632-1634 (1994).]

Anti-fungal agents include three main groups. The major group includes polyene derivatives, including amphotericin B and the structurally related compounds nystatin and pimaricin. These are broad-spectrum anti-fungals that bind to ergosterol, a component of fungal cell membranes, and thereby disrupt the membranes. Amphotericin B is usually effective for systemic mycoses, but its administration is limited by toxic effects that include fever and kidney damage, and other accompanying side effects such as anemia, low blood pressure, headache, nausea, vomiting and phlebitis. The unrelated anti-fungal agent flucytosine (5-fluorocytosine), an orally absorbed drug, is frequently used as an adjunct to amphotericin B treatment for some forms of candidiasis and cryptococcal meningitis. Its adverse effects include bone marrow depression with leukopenia and thrombocytopenia.

The second major group of anti-fungal agents includes azole derivatives which impair synthesis of ergosterol and lead to accumulation of metabolites that disrupt the function of fungal membrane-bound enzyme systems (e.g., cytochrome P450) and inhibit fungal growth. Significant inhibition of mammalian P450 results in significant drug interactions. This group of agents includes ketoconazole, clotrimazole, miconazole, econazole, butoconazole, oxiconazole, sulconazole, terconazole, fluconazole and itraconazole. These agents may be administered to treat systemic mycoses. Ketoconazole, an orally administered imidazole, is used to treat nonmeningeal blastomycosis, histoplasmosis, coccidioidomycosis and paracoccidioidomycosis in non-immunocompromised patients, and is also useful for oral and esophageal candidiasis. Adverse effects include rare drug-induced hepatitis; ketoconazole is also contraindicated in pregnancy. Itraconazole appears to have fewer side effects than ketoconazole and is used for most of the same indications. Fluconazole also has fewer side effects than ketoconazole that is used for oral and esophageal candidiasis and cryptococcal meningitis. Miconazole is a parenteral imidazole with efficacy in coccidioidomycosis and several other mycoses, but has side effects including hyperlipidemia and hyponatremia.

The third major group of anti-fungal agents includes allylaminesthiocarbamates, which are generally used to treat skin infections. This group includes tolnaftate and naftifine.

Another anti-fungal agent is griseofulvin, a fungistatic agent which is administered orally for fungal infections of skin, hair or nails that do not respond to topical treatment.

Most endemic mycoses are acquired by the respiratory route and are minimally symptomatic; cough, fever, headache, and pleuritic pain may be seen. Occasionally, endemic mycoses may cause progressive pulmonary disease or systemic infection. Histoplasmosis, caused by Histoplasma, is the most common endemic respiratory mycosis in the United States; over 40 million people have been infected. The disease is noncontagious and ordinarily self-limited, but chronic pulmonary infection and disseminated infection may occur. Pulmonary infection rarely requires treatment, but disseminated infection may be treated with amphotericin B. Coccidioidomycosis, caused by Coccidioides, is a noncontagious respiratory mycosis prevalent in the southwest. It also is usually serf-limited but may lead to chronic pulmonary infection or disseminated infection. Amphotericin B or miconazole may be given for treatment. Blastomycosis, caused by Blastomyces is a noncontagious, subacute or chronic endemic mycosis most commonly seen in the southeast. Most pulmonary infections are probably self-limited. Patients with progressive lung disease or disseminated disease, and immunocompromised patients, may be treated systemically with amphotericin B. Paracoccidioidomycosis, caused by Paracoccidioides, is a noncontagious respiratory mycosis that is the most common systemic mycosis in South America. It may be acute and self-limited or may produce progressive pulmonary disease or extrapulmonary dissemination. Disseminated disease is generally fatal in the absence of therapy. Sulfonamides may be used but have a low success rate. Amphotericin B produces a higher response rate but relapses may still occur.

Cryptococcosis is a noncontagious, often opportunistic mycosis. It is characterized by respiratory involvement or hematogenous dissemination, often with meningitis. A major etiologic agent is C. neoformans. Most pulmonary infections are probably overlooked, but cryptococcal meningitis, which accounts for 90% of reported disease, is dramatic and seldom overlooked. Cryptococcosis is a particular problem in immunocompromised patients; cryptococcal meningitis occurs in 7 to 10% of AIDS patients. The principal symptom of meningitis is headache; associated findings include mental changes, ocular symptoms, hearing deficits, nausea, vomiting, and seizures. Without treatment, 80% of patients die within two years. In meningitis, cryptococci can be observed in India ink preparations of cerebrospinal fluid sediment, and can be cultured from the cerebrospinal fluid. Treatment is generally with fluconazole or the combination of amphoteficin B and flucytosine, although amphoteficin B does not cross the blood brain barrier.

Aspergillosis is a term that encompasses a variety of disease processes caused by Aspergillus species. Aspergillus species are ubiquitous; their spores are constantly being inhaled. Of the more than 300 species known, only a few are ordinarily pathogenic for man: A. fumigatus, A. flavus, A. niger, A. nidulans, A. terreus, A. sydowi, A. flavatus, and A. glaucus. Aspergillosis is increasing in prevalence and is particularly a problem among patients with chronic respiratory disease or immunocompromised patients. Among immunocompromised patients, aspergillosis is second only to candidiasis as the most common opportunistic mycosis and accounts for about 15% of the systemic mycoses in this group. Opportunistic pulmonary aspergillosis is characterized by widespread bronchial erosion and ulceration, followed by invasion of the pulmonary vessels, with thrombosis, embolization and infarction. Clinically, infection manifests as a necrotizing patchy bronchopneumonia, sometimes with hemorrhagic pulmonary infarction. In about 40% of eases, there is hematogenous spread to other sites. Aspergillosis is also a rare but devastating complication of bum wounds; amputation is often required for cure. Invasive aspergillosis is commonly fatal, so aggressive diagnosis and treatment is required. Blood, urine and cerebrospinal fluid cultures are rarely positive, but fungi can be seen in smears and biopsies. Amphoteficin B can be given for treatment.

Mucormycosis is an acute suppurative opportunistic mycosis that produces rhinocerebral, pulmonary or disseminated disease in immunocompromised patients, and local or disseminated disease in patients with bums or open wounds. Infection is caused by fungi in the class Zygomycetes, and include Basidiobolus, Conidiobolus, Rhizopus, Mucor, Absidia, Mortierella, Cunninghamella, and Saksenaea. Rhinocerebral mucormycosis accounts for about half of all cases of mucormycosis. It is one of the most rapidly fatal funga diseases, with death occurring within 2-10 days in untreated patients. Early clinical signs include nasal stuffiness, bloody nasal discharge, facial swelling and facial pain. The infection then spreads to the eyes, cranial nerves and brain. Pulmonary mucormycosis is nearly as common as rhinocerebral disease and manifests with the same necrotizing and infarction as aspergillosis. Fungi are virtually never seen or cultured from blood, sputum or cerebrospinal fluid. Disseminated mucormycosis may follow pulmonary or bum wound infection. Treatment is with amphotericin B.

Candidiasis is a general term for a variety of local and systemic processes caused by colonization or infection of the host by species of the yeast Candida. Candidiasis occurs worldwide; superficial infections of the skin, mouth and other mucus membranes are universal. Invasive systemic disease has become a problem due to the use of high doses of antibiotics that destroy normal bacterial flora, immunosuppressive agents, and agents toxic to bone marrow, e.g., during cancer therapy. Neutropenia is a major risk factor for Candida dissemination. Candidiasis is also seen among immunocompromised individuals such as AIDS patients, organ transplant patients, patients receiving parentera nutrition, and cancer patients undergoing radiation treatment and chemotherapy. It is the most common opportunistic mycosis in the world. The most common etiologic agent is Candida albicans. Other infectious species include C. tropicalis, C. parapsilosis, C. stellatoidea, C. krusei, C. parakrusei, C. lusitanae, C. pseudotropicalis, C. guilliermondi and C. glabrata. Candida albicans is normally found in the mouth, throat, gastrointestinal tract and vagina of humans. Non-albicans species frequently colonize skin. Candida species occur in two forms that are not temperature- or host-dependent. The usual colonizing form are yeasts that may assume a pseudomycelial configuration, especially during tissue invasion. Pseudomyceliae result from the sequential budding of yeasts into branching chains of elongated organisms.

Candida albicans contains cell wall mannoproteins that appear to be responsible for attachment of the yeast cells to specific host tissues. It has been reported that the mannan portion, rather than the protein portion, of the mannoproteins is responsible for adherence of fungal cells to spleen and lymph node tissues in mice. [Kanbe et al., Infection Immunity, 61:2578-2584 (1993).]

C. albicans also binds avidly to extracellular matrix (ECM) proteins such as fibronectin, laminin, and types I and IV collagen, all of which contain heparin-binding domains. This suggests C. albicans may express a heparin-like surface molecule. Adherence of C. albicans to the ECM may be important in the pathogenesis of disseminated candidiasis. It has been demonstrated that hepafin, heparan sulfate and dextran sulfate glycosaminoglycans (GAGs) inhibit adherence of C. albicans to ECM and ECM proteins, possibly by a mechanism involving binding of GAGs to ECM proteins, thus masking these selective ligands. [Klotz et at., FEMS Microbiology Letters, 78:205-208 (1992).]

Clinically, candidiasis manifests as superficial mucocutaneous infections, chronic mucocutaneous candidiasis, or systemic infection. Superficial mucocutaneous infections can occur in any area of skin or mucus membrane. Thrush, commonly seen in AIDS patients, is characterized by a patchy or continuous, creamy to gray pseudomembrane that covers the tongue, mouth, or other oropharyngeal surfaces and may be accompanied by ulceration and necrosis. Laryngeal involvement results in hoarseness. Esophagitis is often an extension of oropharyngeal disease and may manifest with symptoms of retrosternal pain and dysphagia. Intestinal candidiasis is commonly asymptomatic, but is a major source of hematogenous invasion in immunocompromised individuals. Intertrigo involves the axillae, groins, inframammary folds, and other warm, moist areas, and may manifest as red, oozing or dry, scaly lesions. Infections may occur in other areas, including perianal and genital areas. Paronychia, infection of the nails, often follows chronic exposure of the hands or feet to moisture. Some patients with limited T-cell immunodeficiency develop chronic mucocutaneous candidiasis. These patients suffer from persistent superficial Candida infection of the skin, scalp, nails and mucus membranes.

Most cases of systemic candidiasis are caused by Candida albicans and C. tropicalis, and increasingly, C. glabrata. Clinical manifestations of Candida infection appear mainly in the eyes, kidneys and skin. In the eyes, there may be single or multiple raised, white, fluffy chorioretinal lesions. These lesions are a potential cause of blindness. Involvement of the kidneys includes diffuse abscesses, capillary necrosis and obstruction of the ureters. Infection may result in progressive renal insufficiency. Systemic Candida infection can also manifest as maculonodular skin lesions surrounded by a reddened area; these lesions have an appearance similar to acne but are a major clue to a potentially lethal disease. Other manifestations of systemic candidiasis may include osteomyelitis, arthritis, meningitis, and abscesses in the brain, heart, liver, spleen and thyroid. Involvement of the lungs is also common, but pulmonary lesions are usually too small to be seen on chest X-ray. Finally, Candida endocarditis can occur in patients receiving prolonged intravenous therapy or cardiac valve implants, or in intravenous drug abusers. Fungal lesions appear on the valves, and can embolize and occlude large blood vessels.

Superficial infections are diagnosed by microscopic examination of scrapings or swabs of infected lesions in the presence of 10% potassium hydroxide. Candida organisms can also be seen on gram stain. Endocarditis is diagnosed by blood cultures or demonstration of bulky valvular lesions on echocardiography. Systemic candidiasis may be difficult to diagnose because the presence of heavy colonization at the usual sites of infection indicates, but does not prove, that dissemination has occurred. The most reliable evidence of systemic candidiasis is biopsy demonstration of tissue invasion or recovery of yeast from fluid in a closed body cavity, such as cerebral spinal fluid, pleural or peritoneal fluid. Similarly, positive blood or urine or sputum cultures may indicate invasive disease or simply localized disease around indwelling devices, e.g., catheters or intravenous lines.

Mucocutaneous infections may be treated with topical preparations of nystatin, amphotericin B, clotrimazole, miconazole, haloprogin or gentian violet. Oropharyngeal or esophageal candidiasis can be treated with systemic agents such as ketoconazole or fluconazole. Chronic mucocutaneous candidiasis syndrome may respond to topical or systemic therapeutic agents such as amphotericin B or ketoconazole, but often relapses when medication is discontinued. Cystitis may be treated with amphotericin B bladder rinses, or a brief low-dose intravenous course of amphotericin B with or without oral flucytosine. Endocarditis is essentially incurable without valve replacement, accompanied by a 6 to 10 week course of amphotericin B and flucytosine. Even with therapy, however, complete cure of endocarditis is not always possible.

The mortality rate from systemic candidiasis is about 50%. Systemic candidiasis may be treated with fluconazole, a fungistatic agent, or amphotericin B, a fungicidal agent although systemic use of the latter is limited by its toxicity. Both drugs have substantial adverse reactions when used in combination with cyclosporine A, which itself can be nephrotoxic. The removal of precipitating factors such as intravenous lines or catheters is also important for controlling infection. Flucytosine therapy can be added to the amphotericin B therapy for treatment of systemic candidiasis, especially in patients that are not immunocompromised. In immunocompromised patients, however, these infections are problematic and resist effective treatment. Mortality with systemic candidiasis can be over 90% in such patients. Furthermore, chronic mucocutaneous candidiasis and candidal endocarditis often show evidence of disease after having been declared cured.

There continues to exist a need in the art for new anti-fungal methods and materials. In particular, effective anti-fungal therapy for systemic mycoses is limited. Products and methods responsive to this need would ideally involve substantially non-toxic compounds available in large quantities by means of synthetic or recombinant methods. Ideal compounds would have a rapid effect and a broad spectrum of fungicidal or fungistatic activity against a variety of different fungal species when administered or applied as the sole anti-fungal agent. Ideal compounds would also be useful in combinative therapies with other anti-fungal agents, particularly where these activities would reduce the amount of anti-fungal agent required for therapeutic effectiveness, enhance the effect of such agents, or limit potential toxic responses and high cost of treatment.

Summary of the Invention

The present invention provides methods of treating a subject suffering from a fungal infection by administering a therapeutically effective amount of a BPI protein product. This is based on the surprising discovery that BPI protein products have fungicidal/fungistatic effects. BPI protein products may be administered alone or in conjunction with known anti-fungal agents. When made the subject of adjunctive therapy, the administration of BPI protein products may reduce the amount of anti-fungal agent needed for effective therapy, thus limiting potential toxic response and/or high cost of treatment. Administration of BPI protein products may also enhance the effect of such agents, accelerate the effect of such agents, or reverse resistance of fungi to such agents.

In addition, the invention provides a method of killing or inhibiting growth of fungi comprising contacting the fungi with a BPI protein product. This method can be practiced in vivo or in a variety of in vitro uses such as use to decontaminate fluids and surfaces and to sterilize surgical and other medical equipment and implantable devices, including prosthetic joints and indwelling invasive devices.

A further aspect of the invention involves use of a BPI protein product for the manufacture of a medicament for treatment of fungal infection. The medicament may include, in addition to a BPI protein product, other chemotherapeutic agents such as anti-fungal agents.

Numerous additional aspects and advantages of the invention will become apparent to those skilled in the art upon considering the following detailed description of the invention, which describes the presently preferred embodiments thereof.

Brief Description of the Drawings

FIG. 1 provides results of broth assay tests of the activity of various BPI protein products against C. albicans.

FIGS. 2 and 3 graphically represent survival data in mice after C. albicans challenge and treatment with BPI-derived peptides or buffer.

FIG. 4 graphically represents respiration rate in rats after C. albicans infection and treatment with rBPI.sub.23 or thaumatin.

FIG. 5 graphically represents arterial blood pressure in rats after C. albicans infection and treatment with rBPI.sub.23 or thaumatin.

FIG. 6 graphically represents the number of circulating C. albicans colony forming units in rats after infection and treatment with rBPI.sub.23 or thaumatin.

FIG. 7 graphically represents arterial pH in rats after C. albicans infection and treatment with rBPI.sub.23 or thaumatin.

FIG. 8 graphically represents arterial PO.sub.2 in rats after C. albicans infection and treatment with rBPI23 or thaumatin.

Detailed Description of the Invention

The present invention relates to the surprising discovery that a BPI protein product can be administered to treat subjects suffering from fungal infection, and provides methods of treating such infections. Unexpectedly, BPI protein products were demonstrated to have anti-fungal activities both in in vitro killing assays and in in vivo models of fungal infection, as measured, for example, by improved survival or reduction of colony-forming units in circulation after fungal challenge. A variety of fungal infections, including infections caused by Aspergillosis, infections caused by Cryptococcus, such as cryptococcal meningitis, and mucocutaneous and systemic candidiasis caused by Candida species, may be treated according to the invention.

The BPI protein product may be administered systemically or topically. Systemic routes of administration include oral, intravenous, intramuscular or subcutaneous injection (including into depots for long-term release), intraocular or retrobulbar, intrathecal, intraperitoneal (e.g. by intraperitoneal lavage), transpulmonary using aerosolized or nebulized drag, or transdermal. Topical routes include administration in the form of salves, ophthalmic drops, ear drops, or irrigation fluids (for, e.g., irrigation of wounds). "Effective dosage ranges from about 100 .mu.g/kg to about 100 mg/kg of body weight are contemplated."

The BPI protein product may be administered in conjunction with other anti-fungal agents presently known to be effective. Preferred anti-fungal agents for this purpose are amphotericin B and fluconazole. Concurrent administration of BPI protein product with anti-fungal agents is expected to improve the therapeutic effectiveness of the anti-fungal agents. This may occur through reducing the concentration of anti-fungal agent required to eradicate or inhibit fungal growth, e.g., replication. Because the use of some agents is limited by their systemic toxicity or prohibitive cost, lowering the concentration of anti-fungal agent required for therapeutic effectiveness reduces toxicity and/or cost of treatment, and thus allows wider use of the agent. Concurrent administration of BPI protein product and another anti-fungal agent may produce a more rapid or complete fungicidal/fungistatic effect than could be achieved with either agent alone. BPI protein product administration may reverse the resistance of fungi to anti-fungal agents. BPI protein product administration may also convert a fungistatic agent into a fungicidal agent.

An advantage provided by the present invention is the ability to treat fungal infections, particularly Candida infections, that are presently considered incurable. Another advantage is the ability to treat fungi that have acquired resistance to known anti-fungal agents. A further advantage of concurrent administration of BPI with an anti-fungal agent having undesirable side effects, e.g., amphotericin B, is the ability to reduce the amount of anti-fungal agent needed for effective therapy. The present invention may also provide quality of life benefits due to, e.g., decreased duration of therapy, reduced stay in intensive care units or reduced stay overall in the hospital, with the concomitant reduced risk of serious nosocomial (hospital-acquired) infections.

"Concurrent administration" as used herein includes administration of the agents together, or before or after each other. The BPI protein products and anti-fungal agents may be administered by different routes. For example, the BPI protein product may be administered intravenously while the anti-fungal agents are administered intramuscularly, intravenously, subcutaneously, orally or intraperitoneally. Alternatively, the BPI protein product may be administered intraperitoneally while the anti-fungal agents are administered intraperitoneally or intravenously, or the BPI protein product may be administered in an aerosolized or nebulized form while the anti-fungal agents are administered, e.g., intravenously. The BPI protein product and anti-fungal agents may be both administered intravenously. The BPI protein product and anti-fungal agents may be given sequentially in the same intravenous line, after an intermediate flush, or may be given in different intravenous lines. The BPI protein product and anti-fungal agents may be administered simultaneously or sequentially, as long as they are given in a manner sufficient to allow both agents to achieve effective concentrations at the site of infection.

Concurrent administration of BPI protein product and antibiotic is expected to provide more effective treatment of fungal infections. Concurrent administration of the two agents may provide greater therapeutic effects in vivo than either agent provides when administered singly. For example, concurrent administration may permit a reduction in the dosage of one or both agents with achievement of a similar therapeutic effect. Alternatively, the concurrent administration may produce a more rapid or complete fungicidal/fungistatic effect than could be achieved with either agent alone.

Therapeutic effectiveness is based on a successful clinical outcome, and does not require that the anti-fungal agent or agents kill 100% of the organisms involved in the infection. Success depends on achieving a level of anti-fungal activity at the site of infection that is sufficient to inhibit the fungi in a manner that tips the balance in favor of the host. When host defenses are maximally effective, the anti-fungal effect required may be minimal. Reducing organism load by even one log (a factor of 10) may permit the host's own defenses to control the infection. In addition, augmenting an early fungicidal/fungistatic effect can be more important than long-term fungicidal/fungistatic effect. These early events are a significant and critical part of therapeutic success, because they allow time for host defense mechanisms to activate.

BPI protein product is thought to interact with a variety of host defense elements present in whole blood or serum, including complement, p15 and LBP, and other cells and components of the immune system. Such interactions may result in potentiation of the activities of BPI protein product. Because of these interactions, BPI protein products can be expected to exert even greater activity in vivo than in vitro. Thus, while in vitro tests are predictive of in vivo utility, absence of activity in vitro does not necessarily indicate absence of activity in vivo. For example, BPI has been observed to display a greater bactericidal effect on gram-negative bacteria in whole blood or plasma assays than in assays using conventional media. [Weiss et al., J. Clin. Invest. 90:1122-1130 (1992)]. This may be because conventional in vitro systems lack the blood elements that facilitate or potentiate BPI's function in vivo, or because conventional media contain higher than physiological concentrations of magnesium and calcium, which are typically inhibitors of the activity of BPI protein products. Furthermore, in the host, BPI protein product is available to neutralize translocation of gram-negative bacteria and concomitant release of endotoxin, a further clinical benefit not seen in or predicted by in vitro tests of anti-fungal activity.

It is also contemplated that the BPI protein product be administered with other products that potentiate the activity of BPI protein products, including the anti-fungal activity of BPI protein products. For example, serum complement potentiates the gram-negative bactericidal activity of BPI protein products; the combination of BPI protein product and serum complement provides synergistic bactericidal/growth inhibitory effects. See, e.g., Ooi et al. J. Biol. Chem., 265: 15956 (1990) and Levy et al. J. Biol. Chem., 268:6038-6083 (1993) which address naturally-occurring 15 kD proteins potentiating BPI antibacterial activity. See also co-owned, co-pending PCT Application No. US94/07834 filed Jul. 13, 1994, which corresponds to U.S. patent application Ser. No. 08/274,303 filed Jul. 11, 1994 as a continuation-in-part of U.S. patent application Ser. No. 08/093,201 filed Jul. 14, 1993. These applications, which are all incorporated herein by reference, describe methods for potentiating gram-negative bactericidal activity of BPI protein products by administering lipopolysaccharide binding protein (LBP) and LBP protein products. LBP protein derivatives and derivative hybrids which lack CD-14 immunostimulatory properties are described in PCT Application No. US94/06931 filed Jun. 17, 1994, which corresponds to co-owned, co-pending U.S. patent application Ser. No. 08/261,660, filed Jun. 17, 1994 as a continuation-in-part of U.S. patent application Ser. No. 08/079,510, filed Jun. 17, 1993, the disclosures of all of which are hereby incorporated by reference. It has also been observed that poloxamer surfactants enhance the anti-bacterial activity of BPI protein products, as described in Lambert, U.S. Application No. 08/372,104 filed Jan. 13, 1995, poloxamer surfactants may also enhance the activity of anti-fungal agents.

Without being bound by a theory of the invention, it is believed that BPI protein products may have several modes of action. BPI protein product, through its heparin-binding ability, may interfere with the binding of fungi to the extracellular matrix. For example, heparin-like surface molecules of Candida are believed to mediate adhesion of the yeast to extracellular matrix and host tissues. BPI protein product may also act directly on the cytoplasmic membrane of fungi. In addition, BPI may bind to fungal cell wall mannoproteins that are structurally similar to the LPS of gram-negative organisms or that are responsible for adherence to target host tissues, thus interfering with fungal interaction with host tissues. Binding to fungal mannans may also promote access of BPI protein product to the inner cytoplasmic membrane. Finally, because fungal infection may cause stress-induced translocation of bowel flora and/or LPS, BPI may also act beneficially by killing gram-negative bacteria and neutralizing LPS.

In addition, the invention provides a method of killing or inhibiting growth of fungi comprising contacting the fungi with a BPI protein product. This method can be practiced in vivo or in a variety of in vitro uses such as use in food preparations or to decontaminate fluids and surfaces or to sterilize surgical and other medical equipment and implantable devices, including prosthetic joints. These methods can also be used for in situ sterilization of indwelling invasive devices such as intravenous lines and catheters, which are often foci of infection.

As used herein, "BPI protein product" includes naturally and recombinantly produced BPI protein; natural, synthetic, and recombinant biologically active polypeptide fragments of BPI protein; biologically active polypeptide variants of BPI protein or fragments thereof, including hybrid fusion proteins and dimers; biologically active polypeptide analogs of BPI protein or fragments or variants thereof, including cysteine-substituted analogs; and BPI-derived peptides. The BPI protein products administered according to this invention may be generated and/or isolated by any means known in the art. U.S. Pat. No. 5,198,541, the disclosure of which is incorporated herein by reference, discloses recombinant genes encoding, and methods for expression of, BPI proteins including recombinant BPI holoprotein, referred to as rBPI.sub.50 and recombinant fragments of BPI. Co-owned, copending U.S. patent application Ser. No. 07/885,501 and a continuation-in-part thereof, U.S. patent application Ser. No. 08/072,063 filed May 19, 1993 and corresponding PCT Application No. 93/04752 filed May 19, 1993, which are all incorporated herein by reference, disclose novel methods for the purification of recombinant BPI protein products expressed in and secreted from genetically transformed mammalian host cells in culture and discloses how one may produce large quantities of recombinant BPI products suitable for incorporation into stable, homogeneous pharmaceutical preparations.

Biologically active fragments of BPI (BPI fragments) include biologically active molecules that have the same or similar amino acid sequence as a natural human BPI holoprotein, except that the fragment molecule lacks amino-terminal amino acids, internal amino acids, and/or carboxy-terminal amino acids of the holoprotein. Nonlimiting examples of such fragments include a N-terminal fragment of natural human BPI of approximately 25 kD, described in Ooi et at., J. Exp. Med., 174:649 (1991), and the recombinant expression product of DNA encoding N-terminal amino acids from 1 to about 193 to 199 of natural human BPI, described in Gazzano-Santoro et at., Infect. Immun. 60:4754-4761 (1992), and referred to as rBPI.sub.23. In that publication, an expression vector was used as a source of DNA encoding a recombinant expression product (rBPI.sub.23) having the 31-residue signal sequence and the first 199 amino acids of the N-terminus of the mature human BPI, as set out in FIG. 1 of Gray et at., supra, except that valine at position 151 is specified by GTG rather than GTC and residue 185 is glutamic acid (specified by GAG) rather than lysine (specified by AAG). Recombinant holoprotein (rBPI) has also been produced having the sequence (SEQ ID NOS: 145 and 146) set out in FIG. 1 of Gray et at., supra, with the exceptions noted for rBPI.sub.23 and with the exception that residue 417 is alanine (specified by GCT) rather than valine (specified by GTT). Other examples include dimeric forms of BPI fragments, as described in co-owned and co-pending U.S. patent application Ser. No. 08/212,132, filed Mar. 11, 1994, now U.S. Pat. No. 5,447,913 the disclosures of which are incorporated herein by reference. Preferred dimeric products include dimeric BPI protein products wherein the monomers are amino-terminal BPI fragments having the N-terminal residues from about 1 to 175 to about 1 to 199 of BPI holoprotein. A particularly preferred dimeric product is the dimeric form of the BPI fragment having N-terminal residues 1 through 193, designated rBPI.sub.42 dimer.

Biologically active variants of BPI (BPI variants) include but are not limited to recombinant hybrid fusion proteins, comprising BPI holoprotein or biologically active fragment thereof and at least a portion of at least one other polypeptide, and dimetic forms of BPI variants. Examples of such hybrid fusion proteins and dimeric forms are described by Theofan et al. in co-owned, copending U.S. patent application Ser. No. 07/885,911, and a continuation-in-part application thereof, U.S. patent application Ser. No. 08/064,693 filed May 19, 1993 and corresponding PCT Application No. US93/04754 filed May 19, 1993, which are all incorporated herein by reference and include hybrid fusion proteins comprising, at the amino-terminal end, a BPI protein or a biologically active fragment thereof and, at the carboxy-terminal end, at least one constant domain of an immunoglobulin heavy chain or allelic variant thereof.

Biologically active analogs of BPI (BPI analogs) include but are not limited to BPI protein products wherein one or more amino acid residues have been replaced by a different amino acid. For example, co-owned, copending U.S. patent application Ser. No. 08/013,801 filed Feb. 2, 1993 and corresponding PCT Application No. US94/01235 filed Feb. 2, 1994, the disclosures of which are incorporated herein by reference, discloses polypeptide analogs of BPI and BPI fragments wherein a cysteine residue is replaced by a different amino acid. A stable BPI protein product described by this application is the expression product of DNA encoding from amino acid 1 to approximately 193 or 199 of the N-terminal amino acids of BPI holoprotein, but wherein the cysteine at residue number 132 is substituted with alanine and is designated rBPI.sub.21 .DELTA.cys or rBPI.sub.21. Other examples include dimetic forms of BPI analogs; e.g. co-owned and co-pending U.S. patent application Ser. No. 08/212,132 filed Mar. 11, 1994, now U.S. Pat. No. 5,447,913, the disclosures of which are incorporated herein by reference.

Other BPI protein products useful according to the methods of the invention are peptides derived from or based on BPI produced by recombinant or synthetic means (BPI-derived peptides), such as those described in co-owned and copending PCT Application No. US94/10427 filed Sep. 15, 1994, which corresponds to U.S. patent application Ser. No. 08/306,473, filed Sep. 15, 1994, and PCT Application No. US94/02465 filed Mar. 11, 1994, which corresponds to U.S. patent application Ser. No. 08/209,762, filed Mar. 11, 1994, which is a continuation-in-part of U.S. patent application Ser. No. 08/183,222, filed Jan. 14, 1994, which is a continuation-in-part of U.S. patent application Ser. No. 08/093,202 filed Jul. 15, 1993 (for which the corresponding international application is PCT Application No. US94/02401 fried Mar. 11, 1994), which is a continuation-in-part of U.S. patent application Ser. No. 08/030,644 filed Mar. 12, 1993, the disclosures of all of which are incorporated herein by reference.

Presently preferred BPI protein products include recombinantly-produced N-terminal fragments of BPI, especially those having a molecular weight of approximately between 21 to 25 kD such as rBPI.sub.23 or rBPI.sub.21, or dimeric forms of these N-terminal fragments (e.g., rBPI.sub.42 dimer). Additionally, preferred BPI protein products include rBPI.sub.50 and BPI-derived peptides. Presently preferred BPI-derived peptides include those having an amino acid sequence of BPI protein from about position 142 to about position 169, subsequences thereof and variants of the sequence or subsequence thereof, which possess a BPI anti-fungal biological activity.

The administration of BPI protein products is preferably accomplished with a pharmaceutical composition comprising a BPI protein product and a pharmaceutically acceptable diluent, adjuvant, or carrier. The BPI protein product may be administered without or in conjunction with known surfactants, other chemotherapeutic agents or additional known anti-fungal agents. A stable pharmaceutical composition containing BPI protein products (e.g., rBPI.sub.50, rBPI.sub.23) comprises the BPI protein product at a concentration of 1 mg/ml in citrate buffered saline (5 or 20 mM citrate, 150 mM NaCl, pH 5.0) comprising 0.1% by weight of poloxamer 188 (Pluronic F-68, BASF Wyandotte, Parsippany, N.J.) and 0.002% by weight of polysorbate 80 (Tween 80, ICI Americas Inc., Wilmington, Dela.). Another stable pharmaceutical composition containing BPI protein products (e.g., rBPI.sub.21) comprises the BPI protein product at a concentration of 2 mg/ml in 5 mM citrate, 150 mM NaCl, 0.2% poloxamer 188 and 0.002% polysorbate 80. Such preferred combinations are described in co-owned, co-pending PCT Application No. US94/01239 filed Feb. 2, 1994, which corresponds to U.S. patent application Ser. No. 08/190,869 filed Feb. 2, 1994 and U.S. patent application Ser. No. 08/012,360 filed Feb. 2, 1993, the disclosures of all of which are incorporated herein by reference.

Other aspects and advantages of the present invention will be understood upon consideration of the following illustrative examples wherein Example 1 addresses preparation and in vitro anti-fungal testing of BPI protein products; Example 2 addresses the in vivo effect of BPI protein products on survival rate of mice challenged with Candida; Example 3 addresses additional in vitro and in vivo testing of the anti-fungal effect of BPI protein products on a variety of fungal species; Example 4 addresses the in vivo anti-fungal effect of BPI protein products in rats; and Example 5 addresses further in vivo testing of anti-fungal effects.

Example 1

In Vitro Anti-Fungal Effects

This example addresses in vitro screening of BPI protein products, and specifically BPI-derived peptides, for anti-fungal activity in a broth assay and/or in a radial diffusion assay.

The BPI-derived peptides tested were all prepared according to the procedures described in parent U.S. patent application Ser. Nos. 08/209,762 and 08/183,222. Briefly summarized, peptides were prepared by solid phase peptide synthesis according to the methods of Merrifield, J. Am Chem. Soc. 85: 2149 (1963) and Merrifield et al. Anal. Chem., 38:1905-1914 (1966) using an Applied Biosystems, Inc. Model 432 peptide synthesizer. Alternatively, peptides may be synthesized by the procedure described in Example 2, infra. Peptide design was based in part on the discovery of three functional domains present in the NH.sub.2 -terminal region of the BPI holoprotein: domain I comprising BPI amino acids from about position 17 to about position 45 (SEQ ID NO: 1); domain II comprising BPI amino acids from about position 65 to about 99 (SEQ ID NO: 6); and domain III comprising BPI amino acids from about position 142 to about position 169 (SEQ ID NO: 12). Peptides include sequences and subsequences of the domain sequences and variants thereof, including linear and branched chain combination peptides with and without single or multiple amino acid (including atypical amino acid) substitutions as well as cyclized peptides and interdomain sequence peptides. Table 1 below sets out peptides derived from or based on BPI sequences, which are identified by peptide number with a prefix XMP or BPI (e.g., XMP.1 or BPI.1, XMP.2 or BPI.2, etc.), SEQ ID NO:, amino acid sequence based on reference to position within BPI and designation of amino acid substitutions and additions. Also set out in Table 1 are mass spectroscopy and HPLC estimates of purity of the peptides.

In each broth assay screening procedure, a colony of C. albicans designated CA-1, Strain SLU #1 that was received from the laboratories of G. Matuschak and A. Lechner, St. Louis University Hospital, St. Louis, Mo., where the strain was maintained, was inoculated into a tube containing 5 ml Sabouraud Dextrose broth (2% dextrose, 1% neopeptone) and incubated overnight at 37.degree. C. with shaking. The overnight culture was diluted 1:50 into 5 ml of fresh broth and incubated for 3 hours at 37.degree. C. Organisms were pelleted by centrifugation in a Beckman J-6M centrifuge for 5 minutes at 3000 rpm (1500.times.g) and the pellets were resuspended in 5 ml phosphate buffered saline (PBS) and the optical density at 570 nm was determined. On the basis of the determination that one OD unit equals 3.times.10.sup.7 colony forming units/ml, yeast cells were diluted to 2.times.10.sup.6 cells/ml in Sabouraud Dextrose broth.

Peptides derived from or based on BPI to be screened were originally constituted in Dulbocco's-PBS, were diluted to 100 .mu.g/ml in broth and were serially diluted 2-fold into wells of a 96 well sterile, flat bottom, non-pyrogenic tissue culture plate (Costar, Cambridge, Mass.). All assays were performed in triplicate. 2.times.10.sup.5 organisms were added at 100 .mu.l per well; the plate was incubated on a shaker at 37.degree. C. for 18 hours; and the optical densities for each well were read at 590 nm. FIG. 1 hereto graphically illustrates the dose response curves for five peptides XMP.13, XMP.138, XMP.139, XMP.142 and XMP.143). All illustrated peptides reduced optical density of the cultures to below 0.1 at doses of less than about 50 .mu.g/ml, with XMP.138 displaying the best results of the illustrated peptides at low dosages. Table 1 sets out broth assay data in terms of minimum inhibitory concentration (MIC), i.e. the lowest concentration required to reduce the optical density at 590 nm to below 0.1.

In the radial diffusion assay procedures, yeast CA-1 cultures and peptide solutions were prepared as in the broth assay procedure described above. Ten mL of molten underlayer agarose comprising 3% Sabouraud Dextrose broth, 1% agarose (Pharmacia, Piscataway, N.J.), 0.02% Tween 20, and 10 mM sodium phosphate, at pH 7.4 was added to polystyrene robes and maintained in a 56.degree. C. water bath until the addition of yeast. Tubes were cooled to approximately 45.degree. C., yeast were added to give a final concentration of 1.times.10.sup.6 CFU/ml, and the tubes were mixed again by inverting. The contents were poured into level square petri dishes and distributed evenly. The agarose solidified in less than 30 seconds and had a uniform thickness of about 1 min. A series of wells were punched into the hardened agarose using a sterile 3 mm punch attached to a vacuum apparatus.

Peptides to be assayed were 2-fold serially diluted in Dulbecco's PBS (D-PBS) starting from a concentration of approximately 1 mg/mL. Five .mu.L of each dilution was added to each well and the plates were incubated at 37.degree. C. for 3 hours. An overlayer of 10 mL of molten agarose comprising 6% Sabouraud Dextrose broth, 1% agarose, and 10 mM sodium phosphate, pH 7.4, (at approximately 45.degree. C.) was then added and plates were incubated overnight at 37.degree. C. Following this overnight incubation, a dilute Coomassie solution was poured into the plates and allowed to stain for 24 hours.

Clear zones of growth inhibition around each well were measured with calipers. The actual area of growth inhibition (mm.sup.2) was calculated by subtracting the area of the well. Table 1 below sets out the results of the radial diffusion assays for tested peptides in terms of the number of picomoles (pmol) of peptide required to establish a 30 mm.sup.2 area of growth inhibition.

Peptides XMP.221 through XMP.281 (SEQ ID) NOS: 166 through 226) are prepared and tested for anti-fungal activity as described above.

Further experiments are performed to determine the anti-fungal activity of BPI protein products on strains of Candida considered resistant to other anti-fungal agents: polyene-resistant C. albicans (ATCC Accession No. 38247), 5-fluorocytosine-resistant C albicans (ATCC No. 44373), azole-resistant C. albicans (ATCC No. 62342), and ketoconazole-resistant C. albicans (ATCC No. 64124).

Example 2

In Vivo Anti-Fungal Effect of Bpi Protein Products in Mice With Systemic Candida Infection

This example addresses the in vivo anti-fungal effect of BPI protein products, specifically BPI-derived peptides, in mitigating the total mortality or mortality rate of mice systemically infected with Candida albicans. BPI-derived peptides that had been screened for anti-fungal activity in the radial diffusion and broth assays described in Example 1 were prepared as described in Example 1 and purified as follows.

Fungicidal peptides selected for additional studies were synthesized on a large scale. Peptides were made using solid phase peptide synthesis on an Advanced Chemtech (ACT-Model 357 MPS) synthesizer utilizing a 1-Fluorenylmethyl-oxycarbonyl (Fmoc) protection strategy with a double coupling procedure employing N,N-diisopropylcarbodiimide (DIC)/1-hydroxybenzotriazole (HOBt and 2-(1-H-benzotriazol-1-yl)-1,1,3,3,-tetramethyluronium hexa-fluorophosphate (HBTU)/HOBt/diisopropylethylamine (DIEA).

The solid support used was a polystyrene resin with 1% divinylbenzene (DVB) cross-linking and an 4-(2',4'-dimethoxyphenyl-Fmoc-aminomethyl)-phenoxy (Fmoc-Rink amide) linker with a substitution rate of 0.44 mmoles/gram. The scale used was between 0.5 grams and 5 grams of starting resin. Peptides were purified by HPLC, using a Waters Prep LC 2000 Preparative Chromatography System (Water Corp., Milford, Mass.) equipped with a Delta Pak C-18, 15 um, 300 A cartridge column consisting of a 40.times.10 mm guard cartridge and a 40.times.100 mm Prep Pak cartridge. The column was equilibrated in 25% buffer B, where A=5% acetonitrile/0.1% trifluoroacetic acid and B=80% acetonitrile/0.065% trifluoroacetic acid. Peptides were dissolved to .about.20 mg/mL in buffer A and 200-800 mg were applied to the column through the LC pump operating at a flow rate of 8 mL/min. Bound material was eluted with gradient of 25-35% buffer B/30 min applied at 8 mL/min. (Some peptides were purified with a gradient of 23-33%B/30 min). The eluate was monitored at both 220 and 280 nm with a Waters 490E Programmable Multiwavelength Detector. Fractions were collected and assayed for the peptide of interest on an Ultrafast Micoprotein Analyzer (Michrom BioResources, Inc., Pleasanton, Calif.) equipped with a Zorbax C-8, 150.times.1 mm, 5 um, 300 A maintained at 40.degree. C. Fractions containing the peptide of interest at >95% purity were pooled and lyophilized to dryness.

Five groups of 15 male DBA/2J mice at age 6-8 weeks (Jackson Laboratory, Bar Habor, Me.) were inoculated with 1.24.times.10.sup.5 C. albicans (batch SLU-1 from St. Louis University Medical Center, Mo.) by intravenous injection into the tail vein. A Candida inoculation of 1.times.10.sup.5 results in an LD.sub.80 over 28 days in this model. Immediately after fungal challenge, the mice were intravenously injected via the tail vein with 10 mg/kg XMP.36, 5 mg/kg XMP.97, 10 mg/kg XMP.102, 1 mg/kg amphotericin B (Sigma, St. Louis, Mo.), or 0.1 mL of phosphate buffered saline (PBS) as a control. Treatment with the same amounts of BPI protein products was repeated at Day 2 and Day 4 (except that the second dose of XMP.36 was given at a dose of 5 mg/kg). Mice were monitored twice daily for mortality until termination of the study at Day 28. The mortality data, displayed in FIG. 2, show that 100% of the mice treated with amphotericin B survived, 53% of mice treated with XMP.97 survived (p<0.05 compared to control), 33% of mice treated with XMP.36 survived, 27% of mice treated with XMP.102 survived, and 20% of mice treated with PBS survived until Day 28. In FIG. 2, the symbol "X" represents survival after treatment with amphotericin B; open squares, treatment with XMP.97; open circles, treatment with XMP.36; open diamonds, treatment with XMP.102; and open triangles, treatment with buffer. Statistical significance was evaluated using the Lifetest Survival Curve analysis. [Lawless, Statistical Models and Methods for Lifetime Data, John Wiley & Sons, New York (1982).] The duration and almost linear decline in survival is analogous to human opportunistic candidiasis.

A second experiment was conducted on five groups of 15 mice, with a fungal challenge of 0.5.times.10.sup.5 C. albicans, followed by treatment at Day 0, Day 2 and Day 5 with 10 mg/kg XMP.127, 5 mg/kg XMP.13, 5 mg/kg XMP.37, 1 mg/kg amphotericin B, or 0.1 mL PBS as a control. The mortality data, displayed in FIG. 3, show that 100% of the mice treated with amphotericin B survived, 67% of mice treated with XMP.127 survived (p<0.05 compared to control), 33% of mice treated with XMP.37 survived, 20% of mice treated with XMP.13 survived, and 33% of mice treated with PBS survived until Day 28. In FIG. 3, the symbol "X" represents survival after treatment with amphotericin B; open circles, treatment with XMP.127; filled triangles, treatment with buffer; open squares, treatment with XMP.37; open triangles, treatment with XMP.13.

In these studies, amphotericin B was completely protective, as expected. The effect of XMP.102, a control peptide without anti-fungal activity, was no different than PBS. The data demonstrate that administration of BPI-derived peptides XMP.97 and XMP.127 to mice challenged systemically with C. albicans unexpectedly provided a significant reduction in mortality compared to buffer-treated controls.

Further experiments are performed to confirm the anti-fungal activity of BPI protein products on strains of Candida considered resistant to other anti-fungal agents: polyene-resistant C. albicans (ATCC Accession No. 38247), 5-fluorocytosine-resistant C. albicans (ATCC No. 44373), azole-resistant C. albicans (ATCC No. 62342), and ketoconazole-resistant C. albicans (ATCC No. 64124).

Example 3

In Vitro and in Vivo Effect of Bpi Protein Products on a Variety of Fungal Species

The anti-fungal activity of BPI protein products is evaluated in vitro, e.g., in broth assays, and in vivo in animal models for a variety of fungal species, including Cryptosporidium parvum, Cryptococcus neoformans and Histoplasma capsulatum. Animal models for C. parvum include severe combined immunodeficiency (SCID) mouse models and a colostrum-deprived SPF piglet model.

Example 4

In Vivo Anti-Fungal Effect of Bpi Protein Products in Candida-Infected Neutropenic Rats

This example addresses the in vivo testing of BPI protein products for anti-fungal activity, and specifically the efficacy of a BPI protein product, rBPI.sub.23, in blunting or preventing symptoms of infection and sequelae thereof, including septic shock progression, following infection of neutropenic rats with a massive and lethal dose of a yeast-phase suspension of a clinical isolate of Candida albicans. Treatment of the rats with rBPI.sub.23 (n=6 rats) was compared to treatment with thaumatin (n=5 rats), a control protein having a similar molecular weight and charge but without rBPI.sub.23 's microbicidal effects. During an initial experiment of overwhelming infection with Candida organisms in immunocompromised host animals, animals were monitored for multiple indices including: survival through 24 hours post-infection, systemic arterial pressure, pulse, respiration rate and core temperature, blood cell counts and blood gases, circulating colony-forming units (CFU) of Candida, and the microvascular permeability and histopathology of lungs, livers, hearts, and kidneys. Under such conditions of overwhelming infection, treatment with BPI protein may be expected to have little or no effect on survival but may have effects on other indices monitored during infection.

Specifically, the following procedures were followed. Male Sprague-Dawley rats (initial weight=280-300 g, specific pathogen-free; Harlan, Indianapolis, Ind.) were caged in isolation and permitted free access to food and water before and during experiments. Absolute neutropenia (defined as a combined segmented and band neutrophil count<500 PMN/.mu.l) listing 4-7 days was induced in these animals with 100 mg/kg cyclophosphamide (using a 20 mg/ml solution reconstituted from crystals in sterile phosphate-buffered saline, pH 7.4; Sigma, St. Louis, Mo.) injected intraperitoneally 4 days prior to infection with Candida. On the day before infection, animals were anesthetized with ketamine:xylazine (2:1, 0.9 ml/kg, injected intramuscularly), and the left carotid artery and right jugular vein were aseptically catheterized. Animals received 2.5 mg amikacin sulfate and 300 mg penicillin intravenously immediately after catheterization surgery.

Cultures of Candida albicans (CA) of the CA-1 strain were maintained by weekly transfer to Saboumud dextrose agar slants containing penicillin/streptomycin at 28.degree. C.; these were transferred to Sabouraud's broth, incubated at 37.degree. C. in a shaking water bath for 48-72 hours, and resuspended in fresh Sabouraud's broth for 24 hours before use. Yeast-phase CA Colastoconidia) for infusions were sedimented at 400 .times.g for 10 min at 4.degree. C.), washed twice in saline, and resuspended in saline to 1.times.10.sup.9 organisms/ml using serial dilutions and a hemacytometer, and kept at 4.degree. C. until use. Endotoxin levels in CA infusates were .ltoreq.30 pg/ml as assayed by a quantitative chromogenic Limulus amebocyte lysate assay (Whittaker M. A. Bioproducts, Walkersville, Md.). Viability of CA inocula were confirmed by trypan blue exclusion to be >99%, and microscopic examination before use showed no germination. For CA inocula enumerated as 1.times.10.sup.9 /ml, the actual colony forming units (CFU) were determined to be 5.7.+-.0.2.times.10.sup.8 CFU/ml (mean.+-.SEM) by streak-plated serial dilutions on Sabouraud's dextrose agar at 3.degree. C. for 24 hours.

Animals were treated with 2 mg/ml solutions of either rBPI.sub.23 or the control protein, thaumatin (both in 150 mM NaCl, 5 mM Na-citrate, pH 5.0) before and after CA infection. Five minutes before the start of the CA infusion, rBPI.sub.23 or thaumatin was administered as a 6.6 mg/kg intravenous bolus. The rats were then infected with a massive infusion of organisms over 30 min. (Sage Pump, Cambridge, Mass.) [1.times.10.sup.9 CA in 1 ml which yields an LD.sub.100 in less than 12 hours]. T=0 was considered to be the time at which the CA infusion was completed. Immediately after infection the rats were administered rBPI.sub.23 or thaumatin as a continuous intravenous infusion of 6.6 mg/kg/hour for 4 hours, followed by a saline infusion of 1 ml/hour for the next 4 hours. Infected animals received additional antibiotics (2.5 mg amikacin sulfate and 300 mg penicillin, intravenously) at T=30 min. after the completion of CA infusion. Six neutropenic control rats were sham-infected with saline and received neither rBPI.sub.23 nor thaumatin treatment.

Hemodynamic and vital signs were recorded every 30 min. Arterial pressure (mm Hg) and pulse rates (beats/min.) were continuously recorded on a multichannel physiograph (MK-III-S; Narco Bio-Systems, Houston, Tex.). Respiratory frequency (breaths/min.) was assessed by direct observation, and rectal temperature (.degree.C.) was measured by a miniprobe (Diatek, San Diego, Calif.). A baseline arterial blood sample (1.5 ml) was obtained after a 30 min. equilibration, and additional arterial blood samples were taken at T=1.5 and 4.5 hours (or at death, if occurring earlier). After each blood sample, isovolumetric saline was given via the jugular catheter. These blood samples underwent duplicate analyses of microhematocrit, blood gases using an IL-1306 machine (Instrumentation Laboratory, Lexington, Mass.), total leukocyte and platelet counts by phase microscopy), differential leukocyte counts (Diff-Quik; Baxter, Miami, Fla.), and quantitative blood culture (results in FIG. 6).

Any animal which exhibited convulsions or increasingly severe respiratory distress was humanely sacrificed and was counted as having survived the previous time point. At death, the cranial lobe of the right lung was excised after bronchial ligation for determination of wet/dry weight ratio (W/D), which is an index of altered microvascular permeability and edema, by drying to constant weight at 70.degree. C. Left lungs were fixed in situ with cacodylate-buffered glutaraldehyde for 30 min. at a transpulmonary inflation pressure of 20-22 cm H.sub.2 O, followed by fixation of 2-3 mm midlobar slices in fresh glutaraldehyde overnight at 5.degree. C. before dehydration and embedding in parafin. Serial 6 .mu.m lung sections were stained with hematoxylin and eosin for routine histopathology, periodic acid-Schiff (PAS) to identify yeast, and chloroacetate esterase (CAE) to stain neutrophil granules. Liven, hearts, and kidneys were excised, and standardized tissue sections from these organs were also isolated for W/D determinations, or immersion-fixed in buffered formalin and processed as described above for lung.

Data are presented as means.+-.SEM, with sequential changes for intra- and intergroup variables analyzed by repeated-measures ANOVA and post-hoc comparisons using a Newman-Keuls test. Mortality data were analyzed using Fisher's exact test. Statistical significance was accepted for P-values <0.05.

In this initial experiment, in response to the massive dose of 1.times.10.sup.9 CA, neutropenic rats developed lethal fungemic infection which progressed to shock within 6 hours and which, under these conditions, was not delayed or prevented by treatment with rBPI.sub.23. It should be noted that the rapid onset of lethal shock in many animals resulted in small n-values at later sampling time points. Although no effect on survival was demonstrated with this dose of 1.times.10.sup.9 CA, these BPI.sub.23 -treated rats showed statistically significant enhanced intravascular clearance of circulating CA at 1.5 and 4.5 hours relative to animals receiving thaumatin (p<0.05; see quantitative blood culture results in FIG. 6). Such an anti-fungal effect is surprising and highly significant because reduction of circulating Candida levels even by a factor of 10 can be an important factor in therapeutic success.

With this dose of 1.times.10.sup.9 CA organisms, treatment with rBPI.sub.23 (vs. control protein) did not consistently delay the onset of systemic hypotension and tachypnea with respiratory distress following CA infection. Fungemic circulatory failure in both thaumatin- and rBPI.sub.23 -treated rats was preceded by bradycardia and hypotension which were remarkably abrupt in onset, with the 1.times.10.sup.9 CA-infected animals progressing from hemodynamic stability to death within 15-30 min. Although rBPI.sub.23 did not prolong survival time among such candidemic animals, it did attenuate the severe tachypnea (FIG. 4) and hypotension (FIG. 5) noted by 4.5 hours (or at death, if earlier) in the 1.times.10.sup.9 CA-infected rats treated only with control protein. Thus, rBPI.sub.23 had unexpected beneficial effects in this model of overwhelming CA infection, by dramatically enhancing the introvascular clearance of circulating organisms as shown in FIG. 6 above and by stabilizing both cardiopulmonary indices and vital signs during CA-induced sepsis as shown in FIGS. 4 and 5. Higher or more sustained doses of BPI protein product are expected to achieve greater beneficial effects in this model. BPI protein product is also expected to provide even better effects at the lower levels of CA seen during relevant clinical CA infection.

Lethal candidemia in thaumatin-treated rats was associated with significant arterial acidemia, hypoxemia, and hypercarbia by death at 3-6 hours. Treatment with rBPI.sub.23 slightly attenuated both the arterial acidemia (FIG. 7) and hypoxemia (FIG. 8) during candidemic shock. In all rats studied, the baseline hematological indices of arterial hematocrit, total leukocyte counts, and platelet counts reflected respectively the slight, severe, and moderate decreases induced by cyclophosphamide in this animal model. Higher hematocrits among candidemic rats reflect hemoconcentration due to plasma extravasation, a result which was slightly attenuated by rBPI.sub.23 treatment when compared to results for candidemic animals receiving the control protein thaumatin. Although total arterial leukocyte counts were low at baseline due to pre-treatment with cyclophosphamide, there was a gradual onset of leukopenia among candidemic rats, and there were no significant differences in leukocyte counts between the rBPI.sub.23 and thaumatin treatment groups. Finally, all infected rats developed significant arterial thrombocytopenia, which was evident by 4.5 hours (or at death, if earlier) among candidemic animals; treatment with rBPI.sub.23 did not alter the magnitude or kinetics of peripheral platelet loss compared to thaumatin for any CA-infected group.

Compared to neutropenic control rats which were sham-infected with saline, candidemic rats injected with 1.times.10.sup.9 organisms as described and treated with either control protein (thaumatin) or BPI protein product (rBPI.sub.23) had significantly elevated lung wet/dry weight ratios (W/D) but had lesser increases in liver W/D and kidney W/D. Histological examination of lungs from these animals dying of infection by 1.times.10.sup.9 CA revealed that treatment with rBPI.sub.23 did not alter the rapid development of hemorrhagic pulmonary edema, characterized by severe perivascular and peribronchiolar cuffing and extensive alveolar flooding with fibrin deposition. Candida blastoconidia were observed erupting directly into alveolar airspaces from intravascular yeast aggregates as germinating hyphae. Histological changes in the liver were also severe, with hepatocytes showing both complete glycogen depletion and zonal vacuolation with progressive distance from portal triads and adjacent to germinating CA which had been phagocytized but not killed by sinusoidal Kupffer cells. Although other tissues contained germinated yeast as well, notably the heart and kidney, the overall appearance of these organs was unremarkable except for focal masses of CA hyphae.

Example 5

In Vivo Anti-Fungal Effect of Bpi Protein Products in Candida Neutropenic Rats

This example addresses additional in vivo experiments in view of the beneficial effects of BPI protein product treatment on overwhelming Candida infection (i.e., 1.times.10.sup.9 CA organism dose, as described in Example 2) including specifically the significant reduction of C. albicans colony-forming units in circulation brought about by BPI protein product administration. Additional experiments are carried out using the neutropenic rat model of Candida infection described in Example 2 but wherein lower doses of CA organisms are administered in the animal model and/or increased dosages of BPI protein products are administered, in the same or longer time course, either alone or in combination with known anti-fungal agents. Such experiments are designed to test in a model system designed to more closely approximate typical responses to casual CA infection, the efficacy of BPI protein products in treating fungal infection, including, e.g., protecting against death and fungemic shock.

Numerous modifications and variations in the practice of the invention are expected to occur to those skilled in the art upon consideration of the foregoing description on the presently preferred embodiments thereof. Consequently the only limitations which should be placed upon the scope of the present invention are those that appear in the appended claims.

Claims

Certificate of Correction present

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What is claimed is:

1. A method of treating fungal infections comprising administering to a subject suffering from a fungal infection a therapeutically effective amount of a bactericidal/permeability-increasing (BPI) protein product.

2. The method of claim 1 wherein the BPI protein product is selected from the group consisting of BPI holoprotein, rBPI.sub.23 or rBPI.sub.21.

3. The method of claim 1 wherein the BPI protein product is a BPI-derived peptide selected from the group consisting of XMP.97 (SEQ. ID NO: 92) and XMP.127 (SEQ. ID NO: 123).

4. The method of claim 1 wherein the BPI protein product is administered intravenously.

5. The method of claim 1 wherein the BPI protein product is administered as an aerosol.

6. The method of claim 1 wherein the BPI protein product is a BPI-derived peptide having an amino acid sequence of BPI protein from about position 142 to about position 169, subsequences thereof and variants of the sequence or subsequence thereof, which possess anti-fungal activity.

7. The method of claim 1 wherein the BPI protein product is administered at dosages from about 100 .mu.g/kg to about 100 mg/kg of body weight.

8. The method of claim 1 wherein the BPI protein product is an N-terminal fragment of BPI or dimeric form thereof.

9. The method of claim 8 wherein the N-terminal fragment has a molecular weight of approximately between 21 kD and 25 kD determined by SDS-PAGE analysis.

10. The method of claim 1 wherein the fungal infection involves a fungal species selected from the group consisting of Candida, Aspergillosis, and Cryptococcus species.

11. The method of claim 10 wherein the fungal species is C. albicans.

12. The method of claim 1 comprising the additional step of administering a non-BPI anti-fungal agent.

13. The method of claim 12 wherein the non-BPI anti-fungal agent is amphotericin B.

14. The method of claim 12 wherein the non-BPI anti-fungal agent is fluconazole.

15. A method of killing or inhibiting replication of fungi comprising contacting the fungi with a bactericidal/permeability-increasing (BPI) protein product.

16. The method of claim 15 further comprising contacting the fungal species with an anti-fungal agent.

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