PHARMACEUTICAL COMPOSITIONS FOR THE TREATMENT OF AUTOIMMUNE DISEASES COMPRISING THE B-OLIGOMER OF PERTUSSIS TOXIN OR ITS SUBUNITS

Abstract: The invention provides the use of a protein selected from the B-oligomer of pertussis toxin, an individual subunit S2, S3, S4 or S5 thereof, or a combination of said subunits, for the preparation of pharmaceutical compositions comprising them for the treatment of autoimmune diseases.

Description: PHARMACEUTICAL COMPOSITIONS FOR THE TREATMENT OF AUTOIMMUNE DISEASES COMPRISING THE B-OLIGOMER OF PERTUSSIS TOXIN OR ITS SUBUNITS Field of the Invention The present invention is generally in the field of agents that may be used for the treatment of autoimmune diseases, and more particularly relates to pharmaceutical compositions comprising the B-oligomer of pertussis toxin or one of its subunits S2, S3, S4 or S5, or combinations thereof, useful for protection against autoimmune diseases. Background of the Invention The gram-negative bacterium Bordetella pertussis (B. pertussis), the causative agent of whooping cough, produces several virulence factors. Pertussis toxin (PT), the major virulence component of B. pertussis, appears to contain an important epitope that leads to the formation of antibodies capable of protecting against the disease. Therefore, PT has been extensively investigated with regard to its possible use in preparing vaccines for whooping cough (Black et al., 1988). Pertussis toxin is a 105-kDa hexameric protein composed of five distinct non- n 3li » ntl linked polypeptides designated fin the order of decreasing molecular weight) S1-S5. PT can be divided into two distinct functional units, the enzymatically active toxic A-protomer, consisting of a single polypeptide (SI), and the pentameric B- oligomer (S2, S3, two copies of S4, and S5, i.e. molar ratiol: 1 :2:1). The B-oligomer is responsible for binding of the toxin to the surface of eukaryotic target cells. The two S4 polypeptides form two distinct heterodimers with S2 and S3, which are in rum held together by S5 (see review by Gierschik, 1992). The pertussis toxin gene has been cloned and sequencεd (Nicosia et al.. 1986; European Patent Application EP 0232 229: Locht and Keith, 1986; US Patent 4, 883,761). The individual subunits have been subcloned and expressed in £ coli in non- fusion form (Bumette et al.,1988) or as fusion proteins (Nicosia et al., 1987), and tested as antigens for protecrion against whooping cough. The development of experimental autoimmune encephalomyelitis (EAE), as well as other autoimmune diseases in experimental animals, can be facilitated by injecting Bordetella pertussis concomitantly with inoculation of the autoantigen (Bernard et al., 1992). EAE is a neurological autoimmune disease which can be induced in experimental animals by a single injection of central nervous system (CNS) tissue homogenate or purified myelin antigens such as myelin basic protein (MBP) or proteolipid protein (PLP) in complete Freund's adjuvant (CFA) (Tabira and Kira, 1992). The clinical and pathological features of EAE are reminiscent of multiple sclerosis , and EAE is a well- accepted model for multiple sclerosis. In mice, consistent elicitation of EAE was shown to be facilitated by administration of B. pertussis at the time of the encephalitogenic challenge (Munoz, 1985). Pertussis toxin (PT) was shown later to be the component of B. pertussis responsible for facilitating disease development, and it is now routinely used in place of B. pertussis for enhancement of autoimmune disease in experimental animals (Munoz, 1995). In an analysis of the possible immunomodulating activity of various bacteria, it was found by the present inventor that B. pertussis not only enhances the development of EAE in mice, but can also protect against the disease depending on the time and route of injection (Lehman and Ben-Bun, 1993). The protective activity of B. pertussis was subsequently assigned to PT (Ben-Nun et al., 1993). Pertussis toxin (PT), the major virulence determinant of B. pertussis, is composed of two distinct functional units: the A-protomer consisting of a single polypeptide (SI) that mediates adenosine diphosphate (ADP)-ribosylation of host G proteins, and the B-oligomer, a complex pentamer composed of subunits S2, S3, S4 and S5 in a respective molar ratio of 1 :1:2:1, which mediates the binding of the toxin to host tissue by interaction with glycoproteins and glycolipids on many types of eukaryotic cells (Gierschik, 1992). PT was found to have mitogenic and immunoadjuvant properties (Munoz, 1985). The mechanism by which PT can enhance the development of EAE in mice is not yet clear. However, it has been suggested that PT facilitates the access of autoantigen-specific T cells to the CNS by affecting the vascular permeability of the blood-brain barrier (Linthicum et al., 1982). The mechanism by which PT protects against the development of EAE is also unclear. To further understand how both enhancing and protective activities are mediated by the same, albeit complex, molecule, it is essential to delineate the regions of the PT holomer which may be associated with one or both of these activities. Summary of the Invention It has now been found in accordance with the present invention that the B- oiigomer of pertussis toxin or a subunit S2, S3, S4 or S5 thereof, are able to block the development of EAE in mice. Since EAE is a well-established and widely accepted animal model for the study of autoimmune diseases, these findings indicate that the B- oligomer of pertussis toxin or a subunit S2, S3, S4 or S5 thereof, will be useful for the protection against autoimmune diseases in humans. The present invention thus relates to a pharmaceutical composition comprising as active ingredient the B-oligomer of pertussis toxin or an individual subunit S2, S3, S4 or S5 thereof, or a combination of said subunits, and a pharmaceutically acceptable carrier, useful for protection against autoimmune diseases in humans. Any autoimmune disease can be treated with a pharmaceutical composition of the invention, such as rheumatoid arthritis, systemic lupus erythematosus, insulin- dependent diabetes mellitus and graft-versus-host disease, and more particularly, multiple sclerosis . The invention also relates to the use of the B-oligomer of pertussis toxin or an individual subunit S2, S3, S4 or S5 thereof, or a combination of said subunits, for the manufacture of a pharmaceutical composition useful for the protection against autoimmune diseases in humans. Also encompassed by the present invention is a method for the treatment of a patient afflicted with an autoimmune disease which comprises administering to such a patient an effective amount of the B-oligomer of pertussis toxin or an individual subunit S2. S3, S4 or S5 thereof, or a combination of said subunits. Description of the Figures Fig. 1 depicts the nucleotide and amino acid sequence of the subunit S2 of the B- oligomer of pertussis toxin. Fig.2 depicts the nucleotide and amino acid sequence of the subunit S3 of the B- oligomer of pertussis toxin. Fig. 3 depicts the nucleotide and amino acid sequence of the subunit S4 of the B- oligomer of pertussis toxin. Fig. 4 depicts the nucleotide and amino acid sequence of the subunit S5 of the B- oligomer of pertussis toxin. Fig. 5 shows protection against the development of EAE by PT administered in oil or in aqueous solution. PT (400ng) in 0.1 ml emulsion of IFA or in aqueous solution (PBS) was injected s.c. in the flanks, 18 days prior to the encephalitogenic challenge. X denotes mortality of all mice in the group.P and M represent incidence of paralysis and mortality, respectively, in each group, a) p = 0.0002, and b) p = 0.0012, when compared to P or M, respectively, in the combined controls (None + IFA). Fig. 6 shows that the B-oligomer blocks the development of EAE. B-oligomer (100 ng) or PT (400 ng) emulsified in IFA were injected s.c. 16 days prior to the encephalitogenic challenge, a) p = 0.001, and b) p = 0.001 when compared to P or M, respectively, in the combined controls (None + IFA). Fig. 7 shows silver-stained SDS-gel of gel-purified PT subunits. The subunits were isolated by preparative gel electrophoresis and analyzed. Five μg whole PT, 0.4μg purified SI, 0.3μg purified S2, 0.7μg purified S3 and 1.25μg purified S4/S5 were run on the relevant lanes. Fig. 8 shows differential protective effect of die B-oligomer subunits. 100 ng of B-oligomer or of gel-purified subunits were emulsified in IFA and injected s.c. 20 days before the encephalitogenic challenge, a) p = 0.0002, b) p = 0.0043. c) p = 0.0016, and d) p = 0.014 when compared to P in the combined controls (None + IFA); e) p = 0.001, f) p = 0.008 and g) p = 0.04 when compared to M in the combined controls (None + IFA). Fig. 9 shows that the B-oligomer does not promote the development of EAE. PT (400 ng) or B-oligomer (400 ng) were injected IN. immediately, and 48 hours after IYUS95/16 50 mice were injected with MSCH CFA to induce the development of EAE. a) p = 0.004, and p - 0.02 when compared to P or M, respectively, in the +PT group. Detailer. Description of the Invention PT administered in oil or in aqueous solution protects mice against the development of EAE (Fig. 5), which is routinely used as a model for organ-specific T- cell mediated autoimmune diseases, suggesting its potential efficacy for therapy of such diseases. However, the use of PT as a therapeutic agent is rather risky in view of its toxicity. In order to identify regions of PT associated with enhancement or with blocking of disease, both for potential therapeutic use and for a better understanding of the mechanisms of action of PT on autoimmune diseases, the effect of the constitutive units of PT on the development of EAE was investigated according to the present invention. The findings shown herein in the examples that the B-oligomer of PT, which does not contain the toxic SI monomer, has a remarkable protective effect against EAE (Fig. 6), indicate that the B-oligomer is responsible for the protective activity of PT. Furthermore, the failure of the B-oligomer to enhance the development of EAE (Fig. 9) ' indicates that the enhancement of autoimmune diseases by PT is likely to be associated with the SI monomer of PT. Several features of the B-oligomer of PT make it a potentially useful agent for the therapy of autoimmune diseases: i) it is highly potent in blocking the development of EAE; ii) it is devoid of the enhancing activity of PT; and iii) the B-oligomer, which does not comprise the toxic SI monomer, is non-toxic in vivo. The subunits S2, S3, S4 and S5 of the B-oligomer were purified (Fig. 7) and tested for their ability to protect against EAE, in the attempt to assign the protective activity of the B-oligomer to a particular subunit. The findings that each subunit has protective activity (Fig. 8) furtlier indicate that each can be used as a therapeutic agent for autoimmune diseases. Each subunit protected against EAE to a different extent, and the protection conferred was not as complete as that given by the B-oligomer, indicating that various combinations of the subunits in the form of mixtures, e.g. S2+S3, S2+S4. S2+S3+S5, or as heterodimers, e.g. S2/S4, S3/S4, may be more effective in abolishing disease development Hence, the B-oligomer of PT and the subunits of the B-oligomer, individually or in various combinations, are potentially useful agents for the therapy of multiple sclerosis and other autoimmune diseases, such as rheumatoid arthritis, insulin-dependent diabetes mellitus, systemic lupus erythematosus, and graft-versus-host disease. In preferred embodiments, the pharmaceutical compositions of the invention comprise as active ingredient the B-oligomer, the subunit S2 or S3, a mixture of S2 and S3, or of S2, S3 and S5, or a heterodimer S2/S4 or S3/S4, or a mixture of said heterodimers. The B-oligomer of PT is commercially available or can be prepared by any method described in the art, such as for example by dissociation of pertussis toxin into the A protomer and the B-oligomer by affinity chromatography (Tamura et al., 1982; and 1983; Bums et al., 1987), or by combining heterodimer S2/S4, heterodimer S3/S4 and subunit S5 at the 1 : 1 : 1 molar ratio in 2M urea (Tamura et al., 1983). All attempts to prepare recombinant B-oligomer have not been successful. The individual subunits S2, S3, S4 and S5, both native and recombinant, are encompassed by the invention. The native subunits can be prepared, for example, by preparative gel electrophoresis as described according to the present invention (Fig. 7) or by gel filtration (Tamura et al., 1982), and the recombinant subunits as described by- Nicosia et al, 1987, and Burnette et al., 1988. The heterodimers S2 S4 and S3/S4 are also prepared according to Tamura et al., 1982. The pharmaceutical compositions of the invention comprise a pharmaceutically acceptable carrier and as active ingredient the B-oligomer of PT or an individual subunit S2, S3, S4 or S5 thereof, or a combination of said subunits. By "combination" of said subunits it is herein included both mixtures of the subunits, for example a mixture of S2 and S3, or S2 and S4, or a heterodimer S2/S4 and S3/S4 associated similarly to the native molecule, or a mixture of said heterodimers. The pharmaceutical compositions are prepared by mixing the active ingredient with a pharmaceutically acceptable carrier, stabilizers and excipients, and prepared in dosage form, e.g. by lyophilization in dosage vials. They may be administered in all suitable ways, e.g. intravenously, intramuscularly, subcut neously, local injection, topical application or per os, as the case may require. The amount of active compound to be administered will depend on the route of administration, the disease to be treated and the condition of the patient. The invention will now be described in more detail in the following non-limiting examples and their accompanying figures. EXAMPLES Materials and Methods (a) Materials Pertussis toxin (PT) was obtained from Sigma (St Louis, Mo, USA) and also as a kind gift from Dr. D. Teitelbaum (The Weizmann Institute of Science, Rehovot, Israel). The B-oligomer of PT was obtained from List Biological Laboratories Inc. (Campbell, CA). (b) Mice Female SJL/J mice were purchased from Jackson Laboratories ( Bar Harbor, Me, USA). All mice were 2-3 months old when used in the experiments. (c) Induction of EAE EAE was induced in mice as previously described (Ben-Nun and Lando, 1983). Briefly, 0.1 ml of emulsion prepared from mouse spinal cord homogenate (MSCH, 60 mg/ml) emulsified with an equal volume of CFA enriched for M. tuberculosis H37Ra (5mg/ml) was injected s.c. into the mouse footpads. Immediately after and 48 hrs later, PT was injected intravenously (400 ng/mouse). Where stated in the text, the B-oligomer (400 ng mouse) was also used in place of PT to evaluate its effect on disease enhancement. (d) Clinical evaluation, scoring and statistical analysis Following the encephalitogenic challenge, mice were observed daily for clinical signs of EAE. The severity of the clinical manifestations was scored daily for each individual mouse in the treatment group on a scale of 0-6; 0: no clinical signs, 1 : loss of tail tonicity, 2: flaccid tail, 3: hind leg paralysis, 4: hind leg paralysis with hind body paresis, 5: hind and fore leg paralysis, 6: death. Results presented denote the mean score of the treatment group on each given day after encephalitogenic challenge. At the peak of tiie clinical disease, on days 12-17 after encephalitogenic challenge, the standard errors (not shown) were less than 16% of the mean clinical score. Each graph also displays the incidence of paralysis (P) and mortality (M) for each treatment group in order to allow a complete evaluation of the clinical course of EAE. To evaluate the statistical significance of the differences in incidence of paralysis or mortality between treatment and control groups in each experiment, the contingency table analysis was used to calculate the χ : values with the Stat View 512 + program. Due to the relatively small number of mice in each group, the p values given are of χ 2 with continuity correction. (e) Protection against EAE For the induction of protection against the disease, mice were injected s.c. in the flanks with 400 ng of PT, or with 100 ng of B-oligomer or gel-elutεd subunits of the B- oligomer, emulsified in incomplete Freund's adjuvant (IFA). A total volume of 0.1 ml was injected 2-3 weeks prior to encephalitogenic challenge. Where indicated, PT was injected in aqueous solution (PBS) s.c. in the flanks, in a total volume of 0.1 ml. Example 1. Effect of pertussis toxin on the development of EAE Fig. 5 shows that a single injection of PT prior to the encephalitogenic challenge has a dramatic effect on the subsequent development of EAE induced in SJL/J mice by CNS tissue homogenate. PT was remarkably effective in blocking the development of EAE regardless of whether it was administered s.c. as an oil emulsion or an aqueous solution. These results show that PT can not only facilitate the development of autoimmune diseases as previously shown (Munoz, 1985), but also has a strong protective activity which can completely abolish disease development (Ben-Nun et al., 1993). Example 2. Effect of the B-oligomer of pertussis toxin on the development of EAE To identify * regions of the PT molecule that can be associated with the enhancing effect or with the protective activity of PT. the A-protomer and the B-oligomer were investigated. Fig. 6 shows that the B-oligomer, which is devoid of the toxic SI subunit, is sufficient to protect against the development of EAE. The protection against EAE was total with as little as 50-100 ng of B-oligomer per mouse administered as a single injection. B-oligomer was at least as potent as whole PT in protecting mice against the disease. Example 3. Purification of PT subunits by elution from preparative SDS-gels and their effect on the development of EAE In the attempt to assign the protective activity of PT to a particular subunit of the B-oligomer, PT (Sigma) was electrophoresed on preparative SDS-gel according to Lae mli, 1970. Each subunit was located according to stained reference lane on each gel (Fig. 7). The unstained relevant bands were cut out from the gel. Each subunit was eluted from the crushed gel band by passive diffusion, dialysed extensively against double distilled H 2 O in the presence or absence of bovine serum albumin, lyophilised and resuspended in PBS. The B-oligomer, subunits S2, S3 and S4/S5 were tested in vivo for protective activity against the development of EAE. As shown in Fig. 8, each of the subunits had a protective effect. However, although the protective activity of the different subunits was marked, the protection was not as total as that obtained with B-oligomer or whole PT. Example 4. The B-oligomer does not promote development of EAE in mice As mentioned above, PT has a conflicting immunomodulatory effect on autoimmune diseases (Ben-Nun et al., 1993). It can facilitate the development of the disease and also protect against it (as shown here). As the B-oligomer was found to be highly effective in protecting against EAE, its possible enhancing effect on the disease was investigated. Fig. 9 shows that in comparison with PT, that facilitated the development of a disease with severe neurological impairment and high mortality, the B-oligomer had no enhancing effect. Thus, all mice that received PT concomitantly with the encephalitogenic challenge developed severe EAE, whilst all mice that received PBS or B-oligomer remained healthy. References 1. Ben-Nun, A. and Z. Lando. 1983. Detection of cells responding to myelin basic protein by proliferation and selection of T cell lines functional in mediating experimental autoimmune encephalomyelitis (EAE) in mice. J. Immunol. 130:1205. 2. Ben-Nun, A., S. Yossefi and D. Lehman. 1993. Protection against autoimmune disease by bacterial agents, π. PPD and pertussis toxin as proteins active in protecting mice against experimental autoimmune encephalomyelitis. Eur. J. Immunol. 23:689. 3. Bernard, CCA, Mandel, T.E. and Mackay, I.R. 1992. Experimental models of human autoimmune diseases: Overview and prototypes. In The autoimmune diseases II, Rose, N. and Mackay, I.R. (eds), Academic Press, N.Y., p.47. 4. Black, W.J., Munoz, J.J., Peacock, M.J., Schad, P.A., Cowell, J.L., Burchall, J.J., Lim, M., Kent, A., Steinman, L. and Falko , S. 1988. ADP-ribosyltransferase activity of pertussis toxin and immunomodulation by Bordetella pertussis. Science 240:656. 5. Burnette. W.N. et al. 1988. Direct expression of Bordetella pertussis toxin subunits to high levels in Escherichia coli. Bio/Technology 6:699-706. 6. Bums, D.L. et al. 1987. Role of the A Subunit of Pertussis Toxin in Alteration of Chinese Hamster Ovary Cell Morphology. Infection and Immunity 55:24-28. 7. Gierschik. P. 1992. Guanine Nucleotide-Binding Proteins by Pertussis Toxin. Current Topics in Microbiology and Immunology, Springer-Verlag, Berlin, 175:69-96. 8. Laemmli. U.K. 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature (Lond.). 227:680. 9. Lehman, D. and A. Ben-Nun. 1992. Bacterial agents protect against autoimmune disease. I. Mice pre-exposed to Bordetella pertussis or Mycobacterium tuberculosis are highly refractory to induction of experimental autoimmune encephalomyelitis. J. Autoimmun. 5:675. 10. Linthicum. D.S., Munoz, J.J. and Blasken, S. 1982. Acute experimental autoimmune encephalomyelitis in mice. I Adjuvant action of Bordetella pertussis is due to vasoactive amine sensitization and increased vascular permeability of the central nervous system. Cell Immunol. 73:299 11. Locht, C. and Keith, J.M. 1986. Pertussis Toxin Gene: Nucleotide Sequence and Genetic Organization. Science. 232:1258-1264. 12. Munoz, J.J. 1985. In Pertussis toxin, Sekura, R.D., Moss, J. and Vaughan, M. (eds), Academic Press, N.Y. p. 1. 13. Nicosia, A. et al. 1986. Cloning and sequencing of the pertussis toxin genes: Operon structure and gene duplication. Proc. Natl. Acad. Sci. USA. 83:4631-4635. 14. Nicosia, A. et al. 1987. Expression and Immunological Properties of the Five Subunits of Pertussis Toxin. Infection and Immunity. 55 :963-967. 15. Tabira, T. and J.-I. Kira. 1992. Strain and species differences of encephalitogenic deteπninants of myelin basic protein and proteolipid apoprotein. In Myelin: Biology and chemistry , R.E. Martenson, ed. CRC Press, USA. p.783. 16. Tamura, M. et al. 1982. Subunit Structure of Islet- Activating Protein, Pertussis Toxin, in Conformity with the A-B Model. Biochemistry. 21:5516-5522. 1 * 7 Tr..-.,mr, \Λ _i ~\ 100*7 A D Λ l β ■ #" «•.--- T-. Λli<.««.. \λ~;_*,. _,r 1.1.. A -.:..-+;-- Protein, pertussis Toxin, in the Development of the Biological Effects on Intact Cells. J -9/0-. Chem. 258:6756-6761.

Claims: CLAIMS 1. A pharmaceutical composition for the treatment of autoimmune diseases comprising as active ingredient the B-oligomer of pertussis toxin (PT), an individual subunit S2, S3, S4 or S5 of said B-oligomer, or a combination of said subunits, and a pharmaceutically acceptable carrier. 2. A pharmaceutical composition according to claim 1 for the treatment of an autoimmune disease selected form the group comprising multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, insulin-dependent diabetes mellitus and graft- versus-host disease. 3. A pharmaceutical composition according to claim 1 or 2 wherein the active ingredient is the B-oligomer of pertussis toxin. 4. A pharmaceutical composition according to claim 1 or 2 wherein the active ingredient is the subunit S2 or S3 or a mixture of S2+S3 or of S2---S3-S5. 5. A pharmaceutical composition according to claim 1 or 2 wherein the active ingredient is a heterodimer S2/S4 or S3/S4 or a mixture of both. 6. Use of a protein selected from the group comprising the B-oligomer of pertussis toxin, an individual subunit S2, S3, S4 and S5 of said B-oligomer, or a combination of said subunits, for the preparation of a medicament for the treatment of autoimmune diseases. 7. Use according to claim 6 wherein the autoimmune disease is selected from the group comprising multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, insulin-dependent diabetes mellitus and graft-versus-host disease. Use accordins to ciaim 7 wherein the autoimmune disease is multiple sclerosis. 9. Use according to any one of claims 6 to 8 wherein the protein is the B-oligomer of pertussis toxin. 10. Use according to any one of claims 6 to 8 wherein the protein is the subunit S2 or S3 of the B-oligomer of pertussis toxin or a mixture S2+S3 or S2+S3÷S5. 1 1. Use according to any one of claims 6 to 8 wherein the protein is a heterodimer S2/S4 or S3/S4 or a mixture of both. 12. A method for the treatment of a patient afflicted with an autoimmune disease which comprises administering to said patient an effective amount of a protein selected from the group comprising the B-oligomer of pertussis toxin, an individual subunit S2, S3, S4 or S5 thereof, or a combination of said subunits. 13. A method according to claim 12 wherein the autoimmune disease is selected from the group comprising multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, insulin-dependent diabetes mellitus and graft-versus-host disease. 14. A method according to claim 13 for the treatment of a patient afflicted with multiple sclerosis which comprises administering to said patient an effective amount of a protein selected from the B-oligomer of pertussis toxin, the subunit S2 or S3 thereof, or a mixture of the subunits S2-S3 or S2+S3+S5, or a heterodimer S2/S4 or S3/S4 or a mixture of both.

Inventors: BEN-NUN AVRAHAM, BEN-NUN, AVRAHAM
Applicants: BEN NUN AVRAHAM, RYCUS AVIGAIL, YEDA RES & DEV, BEN-NUN, AVRAHAM, RYCUS, AVIGAIL, YEDA RESEARCH AND DEVELOPMENT CO. LTD.
Application year: 1995
Main classification: A61K38
IPC codes: A61K38