[Sialic acids and O-acetyl groups as markers of biological activity of microbial polysaccharides in plague and cholera agents].

AIM: To determine sialic acids and O-acetyl groups content in Yersinia pestis and Vibrio cholerae antigens in order to establish their association with biological activity.

MATERIALS AND

METHODS

The following antigens of Y. pestis EV NIIEG strain--capsular antigen (F1), major somatic antigen (MSA), lipopolysaccharide (LPS), Pla-protease, allergen pestin PP--as well as O-antigens (O-AG) of V. cholerae serogroups O1 and O139 were used in the study. Sialic acids were identified by the thiobarbituric method, and O-acetyl groups--according to Alicino. Specific polysaccharides in the MSA and O-antigens were detected by the immunodiffusion assay.

RESULTS

Sialic acids were found in LPS, Pla-protease, allergen pestin PP, and all cholera O-AG; their absence was demonstrated in MSA and F1. O-acetyl groups were identified in cholera O-AG of both studied serogroups as well as in LPS, Pla-protease, MSA and pestin PP of Y. pestis. Tendency to correlation between O-acetyl groups content in MSA and serological activity titer was observed.

CONCLUSION

Sialic acids and O-acetyl groups identified in carbohydrate-containing antigens of Y. pestis and V. cholerae could be characterized as reaction-active markers of pathogenetic mechanisms of cholera and plague infections as well as immunochemical activity of microbial polysaccharides.