NZ332531A - Oligosaccharide-peptide conjugate and use in treating cholera - Google Patents

Abstract

Use of a saccharide sequence in the preparation of a medicament, capable of being eliminated from the gastro-intestinal tract, for treating cholera and related conditions. The saccharide sequence is covalently attached to a pharmaceutically acceptable solid with inert support through a non-peptidyl compatible linker arm.

Description

332531 ,u\at\°n23 "—ss tntt" NEW ZEALAND PATENTS ACT, 1953 No: Divided out of NZ 305317 Date: Dated 18 April 1996 COMPLETE SPECIFICATION TREATMENT OF CHOLERA We, SYNSORB BIOTECH, ESTC., a company incorporated under the laws of Canada of 201, 1204 Kensington Road N.W., Calgary, Alberta T2N 3P5, Canada, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - 1 (followed by page la) intelleciual property office! of N.Z. I 2 8 OCT 1938 I RECEIVED D I la TREATMENT OF CHOLERA FIELD OF TSLtc This invention relates to the use of a saccharide sequence covalently attached to a pharmaceutical^ acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, in the preparation of a medicament for treating cholera and related conditions in a subject. More specifically, the invention concerns neutralization and elimination of cholera toxin.

REFERENCES The following references are cited in the application as numbers in brackets ([ ]) at the relevant portion of the application. 1. Menitt, Ethan A., et al., "Crystal structure of cholera toxin B-pentamer bound to receptor GM1 pentasaccharide", Protein Science, 3:166-175 (1994). 2. Spangler, Brenda D., "Structure and Function of Cholera Toxin and the Related Escherichia coli Heat-Labile Enterotoxin", Microbiological Reviews, 56, No. 4:622-647 (1992). 3. Eidels, L., et al., Membrane receptors for bacterial toxins, Microbiology Reviews, 47:596-620 (1983). 4. Fishman, Peter H., et al., "Gangliosides as Receptors for Bacterial Enterotoxins", Advances in Lipid Research, 25:165-187 (1993).

!(VJii LimL Y Of liZ | 1 G !"*'> Tv-fl J * RECEIVED i . Lanne et al., "On the role of the caiboxyl group of sialic acid in binding of cholera toxin to the receptor glycosphingolipid, GM1", J. Biochem., 116: 1269-1274 (1994). 6. Schengrund et al., "Binding of Vibrio cholera toxin and heat-labile enterotoxin of Escherichia coli to GM1, derivatives of GM1 and nonlipid oligosaccharide polyvalent ligands", J. Biol. Chem., 264:13233-13237 (1989). 7. Fukuda et al., "Comparison of the carbohydiate-binding specificities of cholera toxin and Escherichia coli heat-labile enterotoxins LTh-I, LTh-IIa, and LTh-IIb", Infect. Immun., 56: 1748-1753(1988). 8. Uesaka et al., "Simple method of purification of Escherichia coli heat-labile enterotoxin and cholera toxin using immobilized galactose", Microb. Path., 16: 71-76 (1994). 9. Tayot et al., "Receptor-specific large-scale purification of cholera toxin on silica beads derivatized with lysoGMl ganglioside", Eur. J. Biochem. 113: 249-58 (1981).

. Parikh et al., "Ganglioside-agarose and cholera toxin", Meth. Enzymol., 34:610-619(1974). 11. Lemieux, R.U., et al., "The properties of a 'synthetic' antigen related to the blood-group Lewis A", J. Am. Chem. Soc., 97:4076-83 (1975). 12. Lemieux, R.U., et al., "Glycoside-Ether-Ester Compounds", U.S. Patent No. 4,137,401, issued January 30, 1979. 13. Lemieux, R.U., et al., "Artificial Oligosaccharide Antigenic Determinants", U.S. Patent No. 4,238,473, issued December 9, 1980. 14. Lemieux, R.U., et al., "Synthesis of 2-Amino-2-DeoxygIycoses and 2-Amino-2-Deoxyglycosides from glycals", U.S. Patent No. 4,362,720, issued December 7, 1982.

. Cox, D., et al. "A New Synthesis of 4-O-a-D-GalactopyranosyI-D-Galacto-Pyranose", Caibohy. Res., 62: 245-252 (1978). 16. Dahm&i, J., et al., "Synthesis of space arm, lipid, and ethyl glycosides of the trisaccharide portion [a-D-Gal-(l-4)-£-D-Gal(l-4)-£-D~Glc] of the blood group p* antigen: preparation of neoglycoproteins", Carbohydrate Research, 127: 15-25 (1984). 17. Garegg, P. J., et al., "A Synthesis of 8-Methoxycarbonyloct-l-yl 0-a-D-GalactopyTanosyl-(l-3)-0-jS-D-Galactopyianosyl-(l-4)-2-Acetamido-2-Deoxy-0-D-Glucopyranoside", Caibohy. Res., 136: 207-213 (1985). 18. Garegg, P. J., et al., "Synthesis of 6- and 6' -deoxy derivatives of methyl 4-0-a-D-galactopyianosyl-£-D-galactopyranoside for studies of inhibition of pyelonephritogenic fimbriated E. coli adhesion to urinary epithelium-cell surfaces", Caibohy. Res., 137: 270-275 (1985). 19. Jacquinet, J. C., et al., "Synthesis of Blood-group Substances, Part 11. Synthesis of the Trisaccharide 0-a-D-Galactopyranosyl-( 1 -3)-O-0-D-galactopyranosyH 1 -4)-2-acetamido-2-deoxy-D-glucopyranose", J.C.S. Per kin, I: 326-330 (1981).

. Koike, K., et al., "Total Synthesis of Globotriaosyl-E and Z-Ceramides and Isoglobotriaosyl-E-Ceramide," Carbohydr. Res., 163: 189-208 (1987). 21. Schaubach, R., et al., "Tumor-Associated Antigen Synthesis: Synthesis of the Gal-a-(l-3)-Gal-jS-(l-4)-GlcNAc Epitope. A specific Determinant for Metastatic Progression?", Liebigs Ann. Chem., 607-614 (1991). 22. Ratcliffe, R.M., et al., "Sialic Acid Glycosides, Antigens, Immunoadsorbents, and Methods for Their Preparation", U.S. Patent No. 5,079,353, issued January 7, 1992. * 23. Okamoto, K., et al., "Glycosidation of Sialic Acid," Tetrahedron, 47: 5835-5857 (1990). 24. Abbas, S.A., et al., "Tumor-Associated Oligosaccharides I: Synthesis of Sialyl-Lewis* Antigenic Determinant", Sialic Acids, Proc. Japan-German Symp. Berlin 22-23 (1988).

. Paulsen, "Advances in Selective Chemical Syntheses of Complex Oligosaccharides", Angew. Chem. Int. Ed. Eng., 21:155-173 (1982). 26. Schmidt, "New Methods for the Synthesis of Glycosides and Oligosaccharides - Are There Alternatives to the Koenigs-Knoir Method?", Angew. Chem. Int. Ed. Eng., 25:212-235 (1986). 27. Fugedi, P., et al., "Thioglycosides as Glycosylating Agents in Oligosaccharide Synthesis", Glycoconjugate J., 4:97-108 (1987). 28. Kameyama, A., et al., "Total synthesis of sialyl Lewis X", Carbohydrate Res., 209: cl-c4 (1991). 29. Ekborg, G., et al., "Synthesis of Three Disaccharides for the Preparation of Immunogens bearing Immunodeterminants Known to Occur on Glycoproteins", Carbohydrate Research, 110: 55-67 (1982).

. Dahmdn, J., et al., "2-Bromoethyl glycosides: applications in the synthesis of spacer-arm glycosides", Carbohydrate Research, 118: 292-301 (1983). 31. Rana, S. S., et al., "Synthesis of Phenyl 2-Acetamido-2-Deoxy-3-0-ot-L-Fucopyranosyl-/3-D-Glucopyranoside and Related Compounds", Carbohydrate Research, 21: 149-157 (1981). 32. Amvam-Zollo, P., et al., "Streptococcus pneumoniae Type XTV Polysaccharide: Synthesis of a Repeating Branched Tetra saccharide with Dioxa-Type Spacer-Arms", Carbohydrate Research, 150:199-212 (1986). 33. Paulsen, H., "Synthese von oligosaccharid-determinanten mit amid-spacer vom typ des T-antigens", Carbohydr. Res., 104:195-219 (1982). 34. Chemyak, A. Y., et al., "A New Type of Carbohydrate-Containing Synthetic Antigen: Synthesis of Carbohydrate-Containing Polyacrylamide Copolymers having the Specificity of 0:3 and 0:4 Factors of Salmonella", Carbohydrate Research, 128: 269-282 (1984).

. Fernandez-San tana, V., et al., "Glycosides of Monoallyl Diethylene Glycol. A New type of Spacer group for Synthetic Oligosaccharides", J. Carbohydrate Chemistry, 8(3): 531-537 (1989). 36. Lee, R.T., et al., "Synthesis of 3-(2-Aminoethylthio) PropylGlycosides", Carbohydrate Research, 37: 193-201 (1974). 37. Armstrong, G.D., et al., "Investigation of shiga-like toxin binding to chemically synthesized oligosaccharide sequences", J. Infect. Dis., 164:1160-1167 (1991). 38. Heerze, L.D. et al., "Oligosaccharide sequences attached to an inert 5 support(SYNSORB) as potential therapy for antibiotic-associated diarrhea and pseudomembranous colitis", J. Infect. Dis., 169:1291-1296 (1994). 39. U.S. Patent Application Serial No. 08/195,009, filed February 14, 1994, by Heerze, et al., for TREATMENT OF ANTIBIOTIC ASSOCIATED DIARRHEA (allowed). 40. U.S. Patent Application Serial No. 08/126,645, filed September 27, 1993 by Armstrong, et al., for DIAGNOSIS AND TREATMENT OF BACTERIAL DYSENTERY. 41. U.S. Patent Application Serial No. 07/996,913, filed December 28, 1992, by Armstrong, for DIAGNOSIS AND TREATMENT OF BACTERIAL DYSENTERY.

The disclosure of the above publications, patents and patent applications are herein incorporated by reference in their entirety to the same extent as if the language of each individual publication, patent and patent application were specifically and individually included herein. background of THE INVENTION Cholera is a severe diarrheal disease that affects approximately 3 million individuals per year worldwide (mainly in less developed countries). It is caused by consuming food or drinking water contaminated with the 6 microorganism Vibrio cholerae. When the organism is ingested, it has the ability to colonize the intestinal tract.

In the small intestine, V. cholerae attaches to the intestinal mucosa and releases exotoxins, the most important being cholera toxin (CT), which act on mucosal cells [1-4]. The action of CT on intestinal cells induces fluid secretion and increased permeability of electrolytes into the small intestine resulting in severe diarrhea and electrolyte imbalance.

Two other toxins are also produced by V. cholerae. They include zona occludens toxin (Zot) which disrupts tight junctions between cells, and accessory cholera enterotoxin (Ace), which causes diarrhea in animals. The role of these two toxins in the overall pathogenesis of the remains unclear.

An additional cytolytic toxin is produced by 01 £1 Tor and 0139 serotypes of V. cholerae. This toxin has a hemolytic and cytotoxic activity which appears to play a role in the pathogenesis of cholera.

Mortality rates are high for infants and children that are inflicted with cholera. The current method of treatment for cholera is to replace fluids and restore electrolyte balance.

Not all strains of V. cholerae are responsible for causing disease. The disease causing strains belong to the 01 serotype which includes the classical and the El Tor biotypes. All other serotypes except for one are thought to be nonvirulent or capable of causing only minor diaiThea. The only non 01 strain of V. cholerae that has been shown to cause full-blown cholera was identified two years ago. It belongs to the 0139 serotype. This serotype has been identified as the causal agent for recent outbreaks of cholera in Asia. It produces all the virulence factors (including CT) associated with the 01 serotypes of V. cholerae.

The virulence factors most important for causing disease are the toxin coregulated pili (Tcp) which allow V. cholerae to colonize the small intestine. Although the host cell receptor has yet to be identified for pili, there is some indirect evidence which suggests that a carbohydrate may be involved. This evidence is based on the finding that individuals who have the 0 blood group are more susceptible to severe cases of cholera while people who are AB blood group positive tend to be somewhat resistant toward the disease. One possible explanation for this finding is that the pili found on V. cholerae may use the O blood group oligosaccharide structure for colonization of the small intestine, thus rendering individuals with the 0 blood group more susceptible to disease.

CT is the virulence factor most responsible for the symptoms of the disease. CT possesses an enzymatic activity which elevates the levels of cyclic AMP (cAMP) in host cells. The increase in cAMP levels alters the ion transport systems within cells thus affecting the osmotic balance within the intestine that leads to diarrhea. CT utilizes the ganglioside GM1 (0Gal(l-3)|SGalNAc(l-4)[aNeuAc(2-3)]0Gal(l-4)/SGlc-ceramide) to bind to host cell receptors.

Cholera toxin (CT) has been shown to bind to several derivatives of the ganglioside GM1 where the carboxyl group of sialic acid had been modified to form a number of C(l) amides [5]. The structure of these compounds is: 0Gal(l-3) jSGalNAc(l-4)[ <*NeuAcR(2-3)] 0Gal(l-4)fSGlc -ceiamide, where R is selected from the group consisting of amide, methylamide, ethylamide, propylamide, and benzylamide of sialic acid.

Other derivatives of GM1 that were shown to bind CT include [6]: 8 0Gal(l-3) 0GalNH2(l-4)[ aNeu-NH2(2-3)] /SGal(l-4)/SGlc-ceramide; /3GaI(l- 3) 0GalNAc(l-4)[ aNeuAcR(2-3)] 0Gal(l~4)/SGlc-ceramide, where R is the methyl ester of sialic acid; jSGal( 1 -3)/3GalNAc( 1 -4)[ a(C7)NeuAc(2-3)] )8Gal(l- 4)0Glc-ceramide; and j3Gal(l-3) 0GalNAc(M)[ aNeuAcR(2-3)] 0Gal(l-4)/SGIc-ceramide, where R is ethanolamineamide.

Other gangliosides which have been shown to bind CT include[6,7J: GM2 (£GalNAc( 1 -4)[aNeuAc(2-3)J jSGal(l-4)/SGlc-ceramide) and GDlb 03Gal(l-3) £GalNAc(l-4)[aNeuAc(2-3)<*NeuAc(2-3)] 0Gal(l-4)0Glc-ceramide.

In addition, highly purified CT preparations have been obtained using lyso GM1 ganglioside or galactose affinity columns [8-10].

With respect to methods of diagnosis of the presence of CT in a sample, one method for detecting Vibrio cholerae in a sample is to culture the sample. The disadvantages of this method include the length of time required and interference by non-pathogenic, i.e., non-toxin producing, V. cholerae strains. Other methods involve the use of specific antisera or monoclonal antibodies.

In view of the above, there is a need for a compound which would treat cholera. A preferred compound would be administered noninvasively, such as orally, and would specifically remove toxin and/or organisms from the intestinal tract.

SUMMARY OF THE INVENTION The present invention provides a use of a saccharide sequence covalently attached to a pharmaceutically acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, in the preparation of a medicament for treating cholera and related conditions in a subject. (followed by page 9a) LLLCIUAL iJhJiJdiiY OftiCL Or N.Z. 2:;J RECEIVED 9a (followed by page 10) The invention also provides a use of a saccharide sequence covalently attached to a pharmaceutically acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, wherein said saccharide sequence binds one or more serotypes of V cholerae, in the preparation of a medicament for treating cholera and related conditions in a subject.

Further provided by the invention is a use of a saccharide sequence covalently attached to a pharmaceutically acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, wherein said saccharide sequence binds one or more serotypes of V cholerae, in the preparation of a medicament for treating cholera and related conditions in a subject, wherein said medicament is capable of being eliminated from the gastrointestinal tract.

Described but not claimed are methods for the treatment of cholera and associated symptoms caused by cholera toxin.

V* uF ;iz. j !5j:j:!;S50 j RECEIVED | c.r\ The reader's attention is also directed to our related New Zealand - j : *"> Patent Specification No. 332434 which provides a use of a saccharide sequence covalently attached to a pharmaceutically acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, in the preparation of a medicament for treating cholera and related conditions mediated by cholera toxin in a subject. Further uses wherein said saccharide sequence binds cholera toxin, and wherein said medicament is capable of being eliminated from the gastrointestinal tract are also provided therein. Also described in New Zealand 332434 are methods of treatment corresponding to the above uses.

The reader's attention is also directed to our related New Zealand Patent Specification No. 305318 which provides a pharmaceutical composition useful in treating cholera and related conditions initiated by cholera toxin, which composition comprises: a) a saccharide sequence covalently attached to a pharmaceutically acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, wherein said saccharide sequence binds cholera toxin; and b) a pharmaceutically acceptable carrier, wherein composition is capable of being eliminate from the gastrointestinal tract.

The reader's attention is also directed to our related New Zealand Patent Specification No. 305317 which provides a pharmaceutical composition useful in treating cholera and related conditions, which composition comprises: a) a saccharide sequence covalently attached to a pharmaceutically acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm. wherein said saccharide sequence binds one or more serotypes of V. cholerae: 253 1 The reader's attention is also directed to our related New Zealand Patent Specification No. 332434 which provides a method to treat cholera and related conditions mediated by cholera toxin in a subject, which method comprises administering to a subject in need of such treatment in an effective amount of a composition comprising a saccharide sequence covalently attached to a pharmaceutically acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, wherein said saccharide sequence binds cholera toxin, and wherein said composition is capable of being eliminated from the gastrointestinal tract.

The reader's attention is also directed to our related New Zealand Patent Specification No. 305318 which provides a pharmaceutical composition useful in treating cholera and related conditions initiated by cholera toxin, which composition comprises: a) a saccharide sequence covalently attached to a pharmaceutically acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, wherein said saccharide sequence binds cholera toxin; and b) a pharmaceutically acceptable carrier, wherein said composition is capable of being eliminated from the gastrointestinal tract.

The present invention provides a method to treat cholera and related conditions in a subject, which method comprises administering to a subject in need of such treatment an effective amount of a composition comprising a saccharide sequence covalently attached to a pharmaceutically acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, wherein said saccharide sequence binds one or more serotypes of V. cholerae, and wherein said composition is capable of being eliminated from the gastrointestinal tract.

The reader's attention is also directed to our related New Zealand Patent Specification No. 305317 which provides a pharmaceutical composition useful in treating cholera and related conditions, which composition comprises: a) a saccharide sequence covalently attached to a pharmaceutically acceptable solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, wherein said saccharide sequence binds one or more serotypes of V. cholerae: and " tC/ual property ofv -of HI. 2 4 DEC 1999 ;i 332531 b) a pharmaceutically acceptable carrier, wherein said composition is capable of being eliminated from the gastrointestinal tract.

The invention of New Zealand Patent Specification No. 305317 also provides a method to bind and remove one or more serotypes of V. cholerae from a sample suspected of containing said organism, which method comprises: a) contacting said sample with a saccharide sequence covalently attached to a solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, wherein said saccharide sequence binds one or more serotypes of V. cholerae, under conditions wherein said organism is absorbed to said support; and b) separating the support containing the absorbed organism from the sample.

The invention of New Zealand Patent Specification No. 305318 also provides a method to bind and remove cholera toxin from a sample suspected of containing said cholera toxin, which method comprises: a) contacting said sample with a saccharide sequence covalently attached to a solid, inert support through a compatible linker arm, which linker arm is a non-peptidyl compatible linker arm, wherein said saccharide sequence binds cholera toxin, under conditions wherein said cholera toxin is absorbed to said support; and b) separating the support containing the absorbed cholera toxin from the sample. i.wiactual property or.. ! of n.z. ■1 SI 24 DEC 1999 1 °a jj I rpri■ "v 032531 brief description of the drawings Figure 1 demonstrates the neutralization of purified cholera toxin cytotonic activity using a panel of SYNSORBs containing various •saccharide sequences. Several SYNSORBs were found to effectively neutralize cholera toxin activity.

Figure 2 illustrates the concentration dependent neutralization of cholera toxin activity using SYNSORB 16, 19, 41, 72, 75 and 88. All these SYNSORBs can effectively neutralize more than about 75 % of cholera toxin activity at a concentration of 20 mg/ml.

Figure 3 demonstrates the neutralization of cholera toxin and cholera cytotoxin activity produced by 0139 V. cholerae using SYNSORB 16, 41, 72, li ..lctual property ofi-. 1 of n.z. ■i IM DEC 1999 75 and 88 at a concentration of 20 mg/ml. Several SYNSORBs were effective at neutralizing both activities.

Figure 4 demonstrates the neutralization of cholera toxin and cholera cytotoxin activity produced by 01 (H Tor biotype) V. cholerae using SYNSORB 16, 41, 72, 75 and 88 at a concentration of 20 mg/ml. Several SYNSORBs were effective at neutralizing both activities.

Figure 5 illustrates the effectiveness of SYNSORBs 16 and 75 at reducing cholera toxin-mediated fluid secretion in rabbit intestinal loops. SYNSORB 75 utilized at a dose of 0.5 g/kg significantly reduced fluid secretion in rabbit intestinal loops that had been treated with purified cholera toxin.

Figure 6 illustrates the effectiveness of SYNSORBs 16 and 75 at reducing cholera toxin-mediated mannitol permeability in rabbit intestinal loops. SYNSORB 75 utilized at a dose of 0.1 g/kg and SYNSORB 16 at a dose of 0.5 g/kg significantly reduced intestinal permeability in rabbit intestinal loops that had been treated with purified cholera toxin.

Figure 7 demonstrates the effectiveness of SYNSORB in binding 01 V. cholerae (classical). The results show that classical biotypes of V. cholerae bind to the surface of SYNSORBs 1, 41, 57 and 90.

Figure 8 demonstrates the effectiveness of SYNSORB in binding 01 V. cholerae (El Tor). The results show that HI Tor biotypes of V. cholerae bind to the surface of SYNSORBs 1, 5, 57 and 72.

Figure 9 demonstrates the effectiveness of SYNSORB in binding 0139 7. cholerae. The results show that 0139 serotypes of V, cholerae bind to SYNSORBs 2, 5, 57 and 90. 12 332531 detailed description of tfte invention a. Definitions As used herein the following terms have the following meanings: The term "cholera" refers to an acute epidemic infectious disease caused by Vibrio cholerae, wherein a soluble toxin elaborated in the intestinal tract by the Vibrio alters the permeability of the mucosa, causing a profuse watery diarrhea, extreme loss of fluid and electrolytes, and a state of dehydration and circulatory collapse, but no gross morphologic change in the intestinal mucosa.

The term "biocompatible" refers to chemical- inertness with respect to human tissues or body fluids. Biocompatible materials are non-sensitizing.

The term "compatible linker arm" refers to a moiety which serves to space the saccharide structure from the biocompatible solid support and which is biofunctional wherein one functional group is capable of binding to a reciprocal functional group of the support and the other functional group is capable of binding to a reciprocal functional group of the saccharide structure. Compatible linker arms preferred in the present invention are non-peptidyl spacer arms.

The term "saccharide" refers to a saccharide group of at least one sugar unit and also encompasses oligosaccharide groups of at least two sugar units.

The term "solid support" refers to an inert, solid material to which the saccharide sequences may be bound via a compatible linker arm. Where use is in vivo, the solid support will be biocompatible.

The term "SYNSORB" refers to synthetic 8-methoxycarbonyloctyl saccharide structures covalently coupled to Chromosorb P™ (Manville Corp., Denver, Colorado) [11], which is a derivatLzed silica particle. 13 lctual property ofh. _ of nz 2 4 DEC 1999 332531 The term "cholera toxin" refers to an enterotoxin of V. cholerae which initiates cholera and related conditions. This toxin has a lectin-like activity.

For purpose of this application, all sugars are referenced using conventional three letter nomenclature. All sugars are assumed to be in the D-form unless otherwise noted, except for fucose, which is in the L-form.

Further all sugars are in the pyranose form.

B. Synthesis Chemical methods for the synthesis of saccharide structures can be accomplished by methods known in the art. These materials are generally assembled using suitably protected individual monosaccharides.

The specific methods employed are generally adapted and optimized for each individual structure to be synthesized. In general, the chemical synthesis of all or part of the saccharide glycosides first involves formation of a glycosidic linkage on the anomeric carbon atom of the reducing sugar or monosaccharide. Specifically, an appropriately protected form of a naturally occurring or of a chemically modified saccharide structure (the glycosyl donor) is selectively modified at the anomeric center of the reducing unit so as to introduce a leaving group comprising halides, trichloroacetimidate, acetyl, thioglycoside, etc. The donor is then reacted under catalytic conditions well known in the art with an aglycon or an appropriate form of a carbohydrate acceptor which possesses one free hydroxyl group at the position where the glycosidic linkage is to be established. A large variety of aglycon moieties are known in the art and can be attached with the proper configuration to the anomeric center of the reducing unit.

Appropriate use of compatible blocking groups, well known in the art of carbohydrate synthesis, will allow selective modification of the synthesized 14 • < —ectuat property oft ; of n.2. 2 M DEC 1999 structures or the further attachment of additional sugar units or sugar blocks to the acceptor structures.

After formation of the glycosidic linkage, the saccharide glycoside can be used to effect coupling of additional saccharide unit(s) or chemically modified at selected positions or, after conventional deprotection, used in an enzymatic synthesis. In general, chemical coupling of a naturally occurring or chemically modified saccharide unit to the saccharide glycoside is accomplished by employing established chemistry well documented in the literature [12-28].

The solid supports to which the saccharide structures of the present invention are bound may be in the form of sheets or particles. A large variety of biocompatible solid support materials are known in the art. Examples thereof are silica, synthetic silicates such as porous glass, biogenic silicates such as diatomaceous earth, silicate-containing minerals such as kaolinite, and synthetic polymers such as polystyrene, polypropylene, and polysaccharides. Solid supports made of inorganic materials are preferred. Preferably the solid supports have a particle size of from about 10 to 500 microns for in vivo use. In particular, particle sizes of 100 to 200 microns are preferred.

The saccharide structure(s) is covalently bound or noncovalently (passively) adsorbed onto the solid support. The covalent bonding may be via reaction between functional groups on the support and the compatible linker arm of the saccharide structure. It has unexpectedly been found that attachment of the saccharide structure to the biocompatible solid support through a compatible linking arm provides a product which, notwithstanding the solid support, effectively removes toxin. Linking moieties that are used in indirect bonding are preferably organic bifunctional molecules of appropriate length (at least one carbon atom) which serve simply to distance the saccharide structure from the surface of the solid support.

IS -fcctual property ofh of n.z. 2 4 DEC 1999 332531 The compositions of this invention are preferably represented by the formula: (SACCHARIDE-Y-R)B- SOLID SUPPORT where SACCHARIDE represents a saccharide group of at least 1 sugar units which group binds to cholera toxin and/or V. cholerae, Y is oxygen, sulfur or nitrogen, R is an aglycon linking arm of at least 1 carbon atom, SOLID SUPPORT is as defined above, and n is an integer greater than or equal to 1. Preferred aglycons are from 1 to about 10 carbon atoms.

Saccharide sequences containing about 1 to 10 saccharide units may be used. Sequences with about 1 to 3 saccharide units are preferred. Preferably, n is an integer such that the composition contains about 0.25 to 2.50 micromoles saccharide per gram of composition.

Numerous aglycon linking arms are known in the ait. For example, a linking arm comprising a para-nitrophenyl group (i.e., -OC^pNOj) has been disclosed [29]. At the appropriate time during synthesis, the nitro group is reduced to an amino group which can be protected as N-trifluoroacetamido. Prior to coupling to a support, the trifluoroacetamido group is removed thereby unmasking the amino group.

A linking arm containing sulfur has been disclosed [30]. Specifically, the linking arm is derived from a 2-bromoethyl group which, in a substitution reaction with thionucleophiles, has been shown to lead to linking arms possessing a variety of terminal functional groups such as -0CH2CH2SCH2C03CH, and -OCH^H^QIVpNH^ These terminal functional groups permit reaction to complementary functional groups on the solid support, thereby forming a covalent linkage to the solid support. Such reactions are well known in the art. 16 .., ..tCTUAL PROPERTY Of*;,: OF N.Z. 24 DEC 1999 332531 A 6-trifluoroacetamido-hexyl linking arm (-CHCH^-NHCOCFj) has been disclosed [31] in which the trifluoroacetamido protecting group can be removed, unmasking the primary a<v\uio group used for coupling.

Other exemplifications of known linking arms include the 7-methoxycarbonyl-3,6, dioxahepty 1 linking arm [32] (-OCHj-CH^OCHjCOjCHj); the 2-(4-methoxycarbonylbutancarboxamido)ethyl [33] (-0CH2CH2NHC(0)(CH2)4C0,CH3); the allyl linking arm [34] (-OCH2CH=CH2> which, by radical co-polymerization with an appropriate monomer, leads to co-polymers; other allyl linking arms [35] are known (-0(CH2CH20)2CH2CH=CHJ. Additionally, allyl linking arms can be derivatized in the presence of 2-aminoethanethiol [36] to provide for a linking arm -OCH2CH2CH2SCH2CH2NH2. Other suitable linking arms have also been disclosed [12-14, 16, 17].

The particular linking employed to covalently attach the saccharide group to the solid support is not critical.

Preferably, the aglycon linking arm is a hydrophobic group and most preferably, the aglycon Unking arm is a hydrophobic group selected from the group consisting of -(CH^gCfO)-, -(CH2)50CH2CH2CH2- and -(CH^gCHiO-.

We have found that synthetic saccharide sequences covalently attached to a biocompatible solid support, e.g., Chromosorb P™ (SYNSORB) may be used to bind cholera toxin and/or V. cholerae. These compositions are useful to treat cholera and associated conditions. SYNSORB is particularly preferred for these compositions because it is non-toxic and resistant to mechanical and chemical deposition. In studies using rats (a widely accepted model for preclinical studies, since they are predictive of human response), SYNSORBs have been found to pass unaffected through the rat gastrointestinal 17 ... —ectual property off,...

OF N.Z. j 2 M DEC 1999 33253 1 tract. They were found to be eliminated completely and rapidly (99% eliminated in 72 hours) following oral administration.

Additionally, the high density of saccharide moieties on SYNSORB is particularly useful for binding cholera toxin, since the toxin is thought to possess multiple saccharide binding sites [2]. The high density of saccharide ligands on SYNSORB is also useful for binding large numbers of V. cholerae.

Non-peptidyl linking arms are preferred for use as the compatible linking arms of the present invention. The use of glycopeptides is not desirable because glycopeptides contain several, often different, saccharides linked to the same protein. Glycopeptides are also difficult to obtain in large amounts and require expensive and tedious purification. Likewise, the use of BSA or HSA conjugates is not desirable, for example, due to questionable stability in the gastrointestinal tract when given orally.

Covalent attachment of a saccharide group containing a cholera toxin or V. cholerae binding unit through a non-peptidyl spacer arm to an inert solid support permits efficient binding and removal of cholera toxin and/or microorganism from a sample to be analyzed for the presence of cholera toxin and/or organism or from the intestine of a patient suffering from cholera.

When the saccharide is synthesized with this compatible linker arm attached (in non-derivatized form), highly pure compositions may be achieved which can be coupled to various solid supports. is -t-ctual property ofh " of n.z. i 2 4 DEC 1999 C. Pharmaceutical Compositions The methods described herein are achieved by using pharmaceutical compositions comprising one or more oligosaccharide structures which bind one or more serotypes of V, cholerae attached to a solid support.

When used for oral administration, which is preferred, these compositions may be formulated in a variety of ways. It will preferably be in liquid or semisolid form. Compositions including a liquid pharmaceutically inert carrier such as water may be considered for oral administration. Other pharmaceutically compatible liquids or semisolids, may also be used. The use of such liquids and semisolids is well known to those of skill in the art.

Compositions which may be mixed with semisolid foods such as applesauce, ice cream or pudding may also be preferred. Formulations, such as SYNSORBs, which do not have a disagreeable taste or aftertaste are preferred. A nasogastric tube may also be used to deliver the compositions directly into the stomach.

Solid compositions may also be used, and may optionally and conveniently be used in formulations containing a pharmaceutically inert carrier, including conventional solid carriers such as lactose, starch, dextrin or magnesium stearate, which are conveniently presented in tablet or capsule form. The SYNSORB itself may also be used without the addition of inert pharmaceutical carriers, particularly for use in capsule form.

Doses are selected to provide neutralization and elimination of cholera toxin and/or elimination of V, cholerae found in the gut of the affected patient. Preferred doses are from about 0.25 to 1.25 micromoles of« saccharide/kg body weight/day, more preferably about 0.5 to 1.0 micromoles of saccharide/kg body weight/day. Using SYNSORB compositions, this 19 "■ IW i I UrtL Pho("'ui'i I V Ci'MuL I Or W.Z. ;; 1 J J V H jO jj RECEIVED j 332531 means about 0.5 to 1.0 gram SYNSORB/kg body weight/day, which gives a concentration of SYNSORB in the gut of about 20 mg/ml. Administration is expected to be 3 or 4 times daily, for a period of one week or until clinical symptoms are resolved. The dose level and schedule of administration may 5 vary depending on the particular saccharide structure used and such factors as the age and condition of the subject. Optimal time for complete removal of cholera toxin activity was found to be about 1 hour at 37° C, using a concentration of SYNSORB of 20 mg in 1 ml sample. Similar conditions can be used to effectively bind and remove V. cholerae from the gut.

Administration of the saccharide-containing compositions during a period of up to seven days will be useful in treating cholera and associated conditions. Also, prophylactic administration will be useful to prevent colorization of the gut by V. cholerae and subsequent development of the disease.

As discussed previously, oral administration is preferred, but formulations may also be considered for other means of administration such as per rectum. The usefulness of these fonnulations may depend on the particular composition used and the particular subject receiving the treatment. These formulations may contain a liquid carrier that may be oily, aqueous, emulsified or contain certain solvents suitable to the mode of administration.

Compositions may be formulated in unit dose form, or in multiple or subunit doses. For the expected doses set forth previously, orally administered liquid compositions should preferably contain about 1 micromole saccharide/ ml. -euuai property off,.. of n.z. 24 DEC 1999 D. Methodology 3 2531 We have found that V. cholerae toxin may be neutralized by certain saccharide sequences which bind the toxin. In particular, synaietic saccharides covalently attached to solid supports via non-peptidyl compatible linker arms have been found to neutralize cholera toxin effectively. Examples of such compositions are certain SYNSORBs, which bind and neutralize cholera toxin activity.

We have also found that V. cholerae bind to certain saccharide sequences that are covalently attached to solid supports via non-peptidyl compatible linker arms. Examples of such compositions are certain SYNSORBs, which bind V. cholerae, thereby preventing the organism from attaching to its host cell receptor in the intestinal tract before it is eliminated.

We have tested the ability of several saccharide sequences attached to Chromosorb P via an 8-methoxylcarbonyloctyl (MCO) spacer arm to neutralize cholera toxin and bind V. cholerae. The structures tested, also referred to as SYNSORBs, are presented in Table 1. As shown in Figures 1-4, the SYNSORBs tested varied in their ability to neutralize at least about 50% of the cholera toxin activity. Figures 7-9 demonstrate the ability of SYNSORB to bind V. cholerae.

The saccharide sequences attached to solid supports useful in the present invention include those which bind cholera toxin. The binding affinity of a saccharide to cholera toxin is readily detectable by a simple in vitro test, as for example, set forth in Example 1 below. For the purposes of this invention, saccharide sequences attached to solid supports which bind cholera toxin means those compositions which reduce endpoint titers from cytotonic activity in Chinese Hamster Ovary (CHO) cell assays by at least 50%, using the assay set forth in the Examples section. 21 ACTUAL PROPERTY off,. OF N.Z. 2 h DEC 1999 332531 Other saccharide sequences attached to solid supports useful in the present invention are those which can bind V. cholerae significantly better (p^O.OS, using appropriate standard statistical methods, such as the Wilcoxon or Student's T-test) than a control support that does not contain any attached saccharide sequences (e.g., Chromosorb P). The binding affinity of an saccharide for V. cholerae is determined as outlined in Example 6 below.

The binding of shiga-like toxins (SLTs) and Clostridium difficile toxin A to chemically synthesized oligosaccharide sequences has been studied [37-41], SLTs are a group of cytotoxins which are made up of two parts: an A subunit and a B oligomer. The B oligomer is the binding portion of the toxin that allows it to bind to host cell receptors. The SLT toxins bind to glycolipid receptors containing the aGal(l-4)£Gal determinant. The A subunit has an enzymatic activity (N-glycosidase) that depurinates 28S ribosomal RNA in mammalian cells. This enzymatic activity abolishes the ability of the toxin-infected cell to perform protein synthesis.

The site for SLT action is endothelial cells found in the kidneys and mesenteric vasculature, and SLTs may cause damage that can result in renal failure and hemoglobin in the urine. SLTs are the causative agent in the hemolytic-uremic syndrome. SLTs may also be partially involved in the pathogenesis of hemorrhagic colitis (bloody diarrhea).

Clostridium difficile toxin A is an enterotoxin that induces fluid secretion, mucosal damage and intestinal inflammation. It serves as a chemoattractant for human neutrophils. Toxin A is a single protein. It causes activation and results in the release of cytokines in monocytes. These inflammatory effects may play an important role in inducing the colonic inflammation seen in pseudomembranous colitis. 22 -ectual PROPERTY OFF, OF N.Z, 2 ♦ DEC 1999

Claims (1)

1. 3'S 2 Vi 1 Toxin A appears to bind to a glycoprotein receptor, the structure of which has yet to be determined. The mechanism of action is not totally understood, but toxin A is thought to enter cells via receptor-mediated endocytosis and affect the actin cytoskeleton of the cell. The toxin A receptor 5 is thought to be linked to a guanine regulatory protein. Toxin A is the first step in the production of CD AD and PMC. In contrast, cholera toxin is an ABS hexameric protein with five identical B subunits and one A subunit. The B-pentamer recognizes and binds to the cells of the intestine through a glycolipid receptor (ganglioside GM1). The A 10 subunit, which is enzymatically active, is then transported to the interior of the cell, where it causes elevated levels of cyclic AMP, leading to the massive loss of fluids which characterizes cholera and related conditions. Previous studies defining the saccharide binding specificity of cholera toxin have identified several structural requirements for toxin binding 15 [1,5-10]. The major structural requirement for cholera toxin binding is /3Gal(l-3)/SGalNAc(l-4)[aNeuAc(2-3)]£Gal [7]. Cholera toxin has also been shown to bind to galactose affinity columns, indicating that terminal galactose sugars are important for toxin binding [8], The importance of terminal galactose sugars is also confirmed in reduced binding of cholera toxin to the ganglioside GM2 20 (/SGalNAc( 1 -4)[aNeuAc(2-3)]£Gal( 1 -4)£Glc-ceramide) [6]. Sialic acid plays a major role in cholera toxin binding [1,5]. Removal of sialic acid from GM1 to form asialo GM1 03Gal(l-3)/SGalNAc(M)£Gal(l-4)/2Glc-ceramide dramatically reduces cholera toxin binding [6], The SYNSORBs chosen for toxin neutralization studies include carbohydrates that incorporate selected segments 25 of the GM1 saccharide structure. Other additional SYNSORBs selected for binding studies contain saccharide sequences that represent analogs of selected sequences in the GM1 ganglioside structure. Saccharide structures comprising a terminal 0Gal(l-3)/?Gal(l-4)$Gal(l) moiety are also useful in the present invention. 23 -ectual property ofh 0FN.Z. 2M DEC 1999 332531 The amount of cholera toxin adsorption to SYNSORB was determined by assaying supernatants for percent of toxin activity remaining relative to controls without any added SYNSORB. Results are shown in Figures 1 and 2. SYNSORBs 16, 19, 41, 72, 75 and 88 were found to effectively remove cholera toxin activity. Four of these SYNSORBs (41, 72, 75 and 88) contained saccharide sequences not previously shown to bind cholera toxin. Thus, we have found that the ability to neutralize cholera toxin is directly related to the saccharide sequences attached to the inert support. The results in Figures 1 and 2 show the importance of the 0Gal(l-3)/SGalNAc linkage for high affinity toxin binding. In addition, we have found that saccharide sequences which possess /2Gal(l-3)/3GalNAc(l-4)/SGal and cnNeuAc(2-3)/3Gal show high affinity toxin binding. -We have further found that cholera toxin binds saccharide sequences having /?Gal(l-3)£Gal linkage. This structure represents an analog of the £Gal(l-3)£GalNAc sequence found in the GM1 structure. The results presented in Figures 1 and 2 show percent toxin activity remaining. These results were obtained in tissue culture assays using Chinese hamster ovary (CHO) cells that showed a reduction in endpoint dilution relative to controls when SYNSORB was added to purified cholera toxin. Several different saccharide sequences attached to solid supports via compatible linker arms have been found to have the ability to neutralize cholera toxin activity. These sequences, and others that also bind cholera toxin, may be used to treat cholera and related conditions. Optimal time for complete removal of cholera toxin activity was found to be about 1 hour at 37° C, using a concentration of SYNSORB of 20 mg in 1 ml sample. Since each gram of SYNSORB contains approximately 0.25 to 1.0 micromoles saccharide, the total amount of saccharide to be given in a daily dose would range from 7.5 to 30 micromoles, using a gut volume of four liters. 24 actual property ofh : of n.z. 2 4 DEC 1999 35 2.5 3 1 The utility of saccharide sequences attached to a solid support via a compatible linker arm to treat cholera was also demonstrated by the ability of SYNSORB compositions to neutralize cholera toxin in an in vivo animal model using rabbits. The results in Figures 5 and 6 and Table 3 show that SYNSORB 5 75 can effectively reduce cholera toxin-mediated fluid secretion and mannitol permeability in ligated rabbit intestinal loops. Further, the conditions used in the rabbit model best approximate the actual conditions found in the human intestine. Treatment of cholera or related conditions may be accomplished by oral 10 administration of compositions containing saccharide sequences covalently bound to a solid support via a compatible linker arm (e.g. SYNSORBs). For example, the SYNSORB has been found to pass through the stomach of rats intact. It then contacts the cholera toxin in the intestinal tract. Subsequent elimination of the intact SYNSORB with cholera toxin bound to it results in 15 elimination of cholera toxin from the patient. The primary virulence factor responsible for attachment of V. cholerae to epithelial cells in the intestine is the toxin coregulated pili. The host cell receptors used for the attachment process have not been determined, but there is indirect evidence that suggests that attachment may be mediated by blood 20 group saccharide sequences found on epithelial cells. The SYNSORBs chosen (Table 1) for bacterial attachment studies include carbohydrates related to the A, B and O blood group structures. Additional SYNSORBs chosen contain saccharide sequences that were shown to bind to cholera toxin. The amount of V. cholerae binding to the surface of SYNSORB was 25 determined by plating suspensions of SYNSORB that had been incubated with a culture of either 01 (Classical and HI Tor) or 0139 V. cholerae (1 x 10s colony forming units (CFU)/ml). Control incubations were done with V. cholerae and Chromosorb P, which does not have any attached saccharide 25 -cCTUAl PROPERTY OFFi .J OF N.Z. 2 4 DEC 1999 •; t ! sequences. The results in Figures 7-9 show that SYNSORBs 1, 2, 5, 571 72 and 90 bind one or more serotypes of V. cholerae. All six of these SYNSORBs contain (saccharide sequences that have not been previously shown to bind V. cholerae. These results also confirm epidemiological evidence that suggests 5 a relationship between blood group and an individual's susceptibility to cholera. Thus, we have found that the ability to bind V. cholerae is directly related to the saccharide sequences attached to the inert support. The results in Figures 7-9 show the importance of the aGalNAc(l-3)[aFuc(l-2)0Gal (Blood group A), aGal(l-3)[aFuc(l-2)0Gal (Blood group B) and aFuc(l-10 2)£Gal(l-4)0GlcNAc (H(O) blood group) linkages for V. cholerae binding. In addition, we have found that saccharide sequences which possess /3GalNAc(l-4)0Gal and 0Gal(l-3)/SGal can also effectively bind V. cholerae. Accordingly, > saccharide sequences comprising #Gal(l-4)/3Gal(2) will be useful in the present invention. 15 Treatment of cholera or related conditions may be accomplished by oral administration of compositions containing (Saccharide sequences covalently bound to a solid support via a compatible linker arm (e.g. SYNSORBs). For example, the SYNSORB has been found to pass through the stomach of rats intact. It then contacts the organism V. cholerae in the intestinal tract. 20 Subsequent elimination of the intact SYNSORB with V. cholerae bound to it results in elimination of the organism from the patient. Also described is the rapid efficient binding of physiological concentrations of cholera toxin or V. cholerae present in biological samples, thus permitting assay of the presence and/or quantity of 25 cholera toxin or organism in these samples. Typically, the biological sample will be a stool sample. The sample may be extracted and prepared using standard extraction techniques. The sample or extract is then contacted with the toxin or organism binding saccharide sequences covalently bound to 26 ' N I l-uLlG i Ij/aL i*1!i T;ur i'j.z-;\r, p*' ;i I \J 1(1 >1 U RECEIVED solid supports via a compatible linker arm under conditions where any cholera toxin or V. cholerae in the sample is absorbed. Cholera toxin or V. cholerae may be measured directly on the surface of the saccharide-containing support using any suitable detection system. For example, radioactive, biotinylated or fluorescently labelled monoclonal or polyclonal antibodies specific for cholera toxin may be used to determine the amount of cholera toxin bound to the support. A wide variety of protocols for detection of formation of specific binding complexes analogous to standard immunoassay techniques is well known in the art. A panel of SYNSORBs (Table 1) was screened for the ability to neutralize purified CT activity. The results in Figure 1 show that SYNSORBs 16, 19, 41, 72 75 and 88 removed 80%, 80%, 80%, 96%, 96% and 80% (n = 2) respectively. The SYNSORBs that bound to CT with higher affinities fit very well with data obtained from X-ray crystallographic studies which showed that the terminal disaccharide sequence (/JGal(l-3)/SGalNAc) as well as the sialic acid sugar from the GM1 structure played major roles in the interaction between toxin and carbohydrate [2]. The results from Figure 1 also showed that Chromosorb P did not appear to bind to CT. Variable amounts of each SYNSORB were incubated with purified CT in order to determine optimal binding conditions. The results from neutralization experiments (Figure 2) showed that SYNSORB used at a concentration of 20 mg/ml should be effective at neutralizing CT activity. To determine whether the optimized conditions were effective at adsorbing CT activity from 01 serotypes of V. cholerae. Crude culture supematants from Classical and HI Tor biotypes of V. cholerae were incubated with SYNSORBs 16, 41, 72,.75 and 88. The results from neutralization experiments with a classical biotype of 01 V. cholerae indicted that CT activity 27 ,... -LCTUAL PROPERTY OFF; ..J OF N.Z. 2 4 DEC 1999 was reduced by 94 ± 3%, 90 ± 0%, 77 ± 0%, 97 ± 0% and 97 ± 0% (n = 4) respectively for each of the SYNSORBs listed above. Using two culture supematants from El Tor biotypes of 01 V. cholerae (NIH V86 and 95-0031), SYNSORBs 16, 41, 72, 75 and 88 reduced CT activity by 81 ± 0%, 75 ± 5 0%, 89 ± 0%, 81 ± 0% and 75 ±0% (n = 2) and 50 ± 0%, 75 ± 0%, 88 ± 0%, 66 ± 0% and 94 ±0% (n = 2) respectively. Preliminary CT neutralization experiments with four 0139 V. cholerae clinical isolates obtained from Dr. W. Johnson, LCDC, Ottawa revealed the presence of a cytotoxic activity that is not found with the classical 01 serotypes 10 of V. cholerae. Two tissue culture assays are useful for detecting CT activity. The classical CT assay involves exposing Chinese hamster ovary (CHO) cells to solutions containing toxin and determining the cytotonic (cell elongation) end point after 24 hours. The second involves HT 29 cells which produce large pleomorphic vacuoles when exposed to CT. Culture supematants from 0139 15 clinical isolates had the ability to rapidly kill CHO cells (100% death in less than 24 hours) and induced vacuolization in HT 29 cells (Table 2). The results from preliminary experiments indicate some differences between the 0139 culture supematants and purified CT. To further explore the differences, neutralization experiments were done 20 with anti-CT antiserum. Dilutions of purified CT and 0139 culture supematants were combined with anti-CT serum and incubated for 30 minutes prior to adding the toxin dilutions to CHO and HT 29 cells. After incubating with toxin for 24 hours, the results indicated that the cytotoxic activity observed with CHO cells was not neutralized by the anti-CT antiserum. 25 Antibody neutralization experiments using HT 29 cells revealed that the antiserum effectively reduced the formation of vacuoles, suggesting the presence of CT in the culture supematants. Control assays using purified CT showed good neutralization in both the CHO and HT 29 cells. 28 332531 The data obtained from the neutralization assays suggest that two toxin activities are produced by 0139 strains. One of the activities is CT, which causes vacuolization in HT 29 cells. The second activity, a cholera cytotoxin (CC) that kills CHO cells. Additional evidence to support the presence of CC in 0139 culture supematants was obtained by incubating toxin containing solutions with Vero cells which have been shown to be resistant towards the effects of CT. Incubating 0139 culture supematants with Vero cells resulted in rapid death of the cells confirming the presence an additional cytotoxic activity. El Tor biotypes of V. cholerae are known to possess an additional cytotoxic/hemolytic activity that is similar to CC produced by 0139 serotypes. Preliminary neutralization studies with SYNSORBs 16, 41, 72, 75 and 88 have shown that SYNSORB has the ability to adsorb CC and CT from culture supematants. The extent of CC neutralization was determined by comparing the cytotoxic end points of SYNSORB treated culture supematants with untreated control samples using CHO cells. CT neutralization experiments were done in a similar manner except that HT 29 cells were used to assess toxin levels. The results in Figure 3 show that SYNSORBs 16, 41, 72, 75 and 88 had the ability to neutralize greater than 50% of CT activity in most cases. The results also show that the cytotoxic activity produced by 0139 serotypes and Ol El Tor biotypes may utilize saccharide receptors similar to those used by CT for interacting with host cells. The ability of SYNSORB to neutralize CT activity from 0139 V. cholerae strains was somewhat reduced when compared to the results obtained with the 01 serotype. The reduced affinities for the various SYNSORBs may be due to slight differences between the two CT activities. E. Examples 29 -ACTUAL PROPERTY OFF;.: OF N.2. 2 4 DEC 1999