BIOLOGICAL PREPARATION AND ITS USE

Abstract: The invention relates to the use of antigenic and/or immunoregulatory material derived from Mycobacterium vaccae for immunoprophylactic treatment against the AIDS syndrome.

Description: BIOLOGICAL PREPARATION AND ITS USE This invention relates to iomunoprophylactic agents useful in immunoprophylaxis against the AIDS (acquired immune deficiency syndrome) syndrome. The causative agent for AIDS is known to be a virus of the retrovirus family known as HIV (human immunodeficiency virus) . Infection with HIV does not, however, immediately give rise to overt symptoms of the AIDS syndrome. The only indication of exposure to the virus may be the presence of antibodies thereto in the blood of an infected subject who is then described as 'HIV positive 1 . The infection may lie dormant, giving rise to no obvious symptoms, and the incubation period prior to development of the AIDS syndrome may vary from several months to decades. Development of AIDS itself may be preceded by the AIDS- related complex (ARC) which is characterised by unexplained fever, weight loss, chronic cough or diarrhoea. The reasons for the variable period between infection with the virus and breakdown of the immune system in an infected individual are poorly understood. Factors at present unknown may trigger proliferation of the virus with consequential disruption of the immune system. The victims of the disease are then subject to various infections and malignancies which, unchecked by the disabled immune system, lead to death. Despite the rapid growth of research into AIDS no SUBSTITUTESHEET vaccine against it is yet available: it has been suggested that the genetic variability of the virus will in fact hamper the search for an effective vaccine. The present invention seeks to provide an immunoprophylactic agent useful in delaying or preventing onset of the AIDS syndrome, i.e. in increasing the period between infection by fflV and development of the AIDS syndrome. Th% present invention provides an immunoprophylactic agent comprising antigenic and/or immunoregulatory material derived from Mycobacterium vaccae for use in immunoprophylactic treatment against the AIDS syndrome. The preparation conveniently, and therefore preferably^ comprises dead cells of M. vaccae. most preferably cells which have been killed by autoclaving. The immunotherapeutic agent normally comprises more than 10 8 microorganisms per ml of diluent, and preferably from 10 8 to 10 11 killed M. vaccae microorganisms per ml of diluent. The invention includes within its scope antigenic and/or immunoregulatory material from M. vaccae for use in therapy in the prophylactic treatment of HIV infection to delay or prevent onset of the AIDS syndrome. The diluent may be pyrogen-free saline for injection alone, or a borate buffer of pH 9.0. The diluent should be sterile. A suitable borate buffer is: The preferred strain of M. vaccae is one denoted R877R isolated from mud samples from the Lango district of Central Uganda (J.L. Stanford and R.C. Paul, Ann. Soc. Beige Med, Trop. 1973, 5_3_, 141-389). The strain is a stable rough variant and belongs to the auru sub-species. It can be identified as belonging to M. vaccae by biochemical and antigenic criteria (R. Bonicke, S.E. Juhasz., Zentr albl. Bakteriol. Parasitenkd. Infection skr. Hyg. Abt. 1, Orig. , 1964, 192. 133) . The strain denoted R877R has been deposited at the National Collection of Type Cultures (NCTC) Central Public Health Laboratory, Colindale Avenue, London NW9 5HT, United Kingdom on February 13th, 1984 under the number NCTC 11659. For the preparation of the immunoprophylactic agent, the microorganism M. vaccae may be grown on a suitable solid medium. A modified Sauton's liquid medium is preferred (S.V. Boyden and E. Sorkin. , J. Immunol, 1955, 75. 15) solidified with agar. Preferably the solid medium contains 1.3% agar. The Medium inoculated with the microorganisms is incubated aerobically to enable growth of the microorganisms to take place, generally at 32°C for 10 days. The organisms are harvested, then weighed and suspended in a diluent. The diluent may be unbuffered saline but is preferably borate- buffered and contains a surfactant such as Tween 80 as described above. The suspension is diluted to give 100 mg of microorganism/ml. For further dilution, borate buffered saline is preferably used so that the suspension contains 10 mg wet weight of microorganisms/ml of diluent. The suspension may then be dispensed into 5 ml multidose vials. Although the microorganisms in the vials may be killed using irradiation e.g. from 60 Cobalt at a dose of 2.5 egarads, or by any other means, for example chemically, it is preferred to kill the microorganisms by autoclaving, for example at 10 psi for 10 minutes (115°-125°C) . It has been discovered, unexpectedly, that autoclaving yields a more effective preparation than irradiation. The immunotherapeutic agent is in general administered by injection in a volume in the range 0.1-0.2 ml, preferably 0.1 ml, given intradermally. A single dosage will generally contain from 10 7 to 10 10 killed M. vaccae microorganisms. It is preferred to administer to patients a single dose containing 10 8 to 10 9 killed M. vaccae. However, the dose may be repeated depending on the condition of the patient. Although the immunotherapeutic agent will generally be administered by intradermal injection other routes, e.g. oral administration, can also be used. The invention includes within its scope a method for the prophylactic treatment against the AIDS syndrome which comprises administering to a subject, for example a subject who has been exposed to infection by HIV or a subject who has developed antibodies to HIV, antigenic and/or immunoregulatory material derived from Mycobacterium vaccae in an amount sufficient to provoke an immune response effective to delay or prevent onset of the AIDS syndrome. For 20 to 50% of African patients with HIV infection tuberculosis is the first symptom in development of the AIDS syndrome. Tuberculosis infection is associated with significant production of interleukin 6 (IL6) and tumour necrosis factor (TNF) . There is evidence to show that the addition of TNF and IL6 to HIV-infected T cells in vitro leads to increased multiplication of the virus. The TNF release associated with tuberculosis infection in an HIV-positive subject may precipitate proliferation of the HIV with consequential disruption of the function of T4 cells in the immune system and production of immunodeficiency. It is believed that the prevention of tuberculosis or, more specifically, the inhibition of TNF, and IL6 associated (Koch) responses, will have a delaying effect on precipitation of the AIDS syndrome. The immunoprophylactic agents of the invention are believed to exert an immuno odulatory effect on pre-existent cell mediated necrotising responses, changing them to a non-necrotising form of response and that this is due to decreased production of, or a change in function of, IL6 and TNF. It is also believed that protective immunity against both tuberculosis and leprosy are enhanced. It may be advantageous and is within the scope of the invention to use more than one strain of M. vaccae. and/or to include in the immunoprophylactic agent other mycobacterial antigens. Tuberculin may also be included. The immunoprophylactic agent may also contain BCG (Bacillus Calmette-Guerin) vaccine, in particular the freeze-dried form of the vaccine, to promote its effect. The immunoprophylactic agent can contain further ingredients such as adjuvants, preservatives, stabilisers etc. It may be supplied in sterile injectable liquid form or in sterile freeze-dried form which is reconstituted prior to use. M. vaccae may be used as such or as an extract or fractionated portion of the organism to prepare immunoprophylactic agents according to the invention. The following Example illustrates the invention. EXAMPLE M. vaccae is grown on a solid medium comprising modified Sauton's medium solidified with 1.3% agar. The medium is inoculated with the microorganism and incubated for 10 days t 32°C to enable growth of the microorganism to take place. The microorganisms are then harvested and weighed and suspended in diluent to give 100 mg of microorganisms/ml of diluent. The suspension is then further diluted with buffered saline to give a suspension containing 10 mg wet weight of microorganisms/ml of diluent and dispensed into 5 ml multidose vials. The vials containing the live microorganism are then autoclaved for 10 minutes at 10 psi to kill the microorganisms and give the immunotherapeutic agent of the invention, which may (if desired) be further diluted for use. This immunotherapeutic agent may be administered by intradermal injection in the manner already described.

Claims: CLAIMS 1. Use of antigenic and/or immunoregulatory material derived from Mycobacterium vaccae for the manufacture of a medicament useful in delaying or preventing onset of the AIDS syndrome. 2. The use according to claim 1, wherein the antigenic and/or immunoregulatory material derived from M. vaccae comprises dead cells of M. vaccae. 3. The use according to claim 2, wherein the cells of M. vaccae have been killed by autoclaving. 4. The use according to any one of the preceding claims wherein the material derived from M. vaccae is derived from the strain as deposited at the National Collection of Type Cultures (NCTC) Central Public Health Laboratory, Colindale Avenue, London NW9 5HT, United Kingdom on February 13th, 1984 under the number NCTC 11659. 5. The use according to any one of the preceding σlaims wherein the material derived from M. vaccae is contained in a medicament comprising from 10 7 to lθ 10 microorganisms per dose. 6. A method for the prophylactic treatment against the AIDS syndrome which comprises administering to a subject, for example a subject who has been exposed to infection by HXV or a subject who has developed antibodies to HIV, antigenic and/or immunoregulatory material derived from Mycobacterium vaccae in an amount sufficient to provoke an immune response effective to delay or prevent onset of the AIDS syndrome. 7. A method according to claim 6, wherein the material derived from M. vaccae is as defined in any one of claims 2 to 5. 8. Products comprising material derived from Mycobacterium vaccae for use in delaying or preventing the onset of the AIDS syndrome. 9. Products according to claim 8, wherein the material derived from M. vaccae is as defined in any one of claims 2 to 5. 10. An immunoprophylactic agent comprising antigenic and/or immunoregulatory material derived from Mycobacterium vaccae for use in immunoprophylactic treatment against the AIDS syndrome. 11. An agent according to claim 10, wherein the material derived from M. vaccae is as defined in any one of claims 2 to 5.

Inventors: ROOK GRAHAM ARTHUR WILLIAM, STANFORD JOHN LAWSON, ROOK, GRAHAM, ARTHUR, WILLIAM, STANFORD, JOHN, LAWSON
Applicants: UNIV LONDON, UNIVERSITY COLLEGE LONDON
Application year: 1990
Main classification: A61K39
IPC codes: A61K35, A61K39, A61P31, A61P37