Production and Characterization of Immune Ascitic Fluids to Vibrio cholerae R-Variant Strains

The aim of the work was to obtain immune ascitic fluids (IAF) of mice to whole cells of R-variant cholera vibrios and to evaluate the possibility of their use for detection and characterization of atypical cholera vibrios. Materials and methods. A cycle of immunization of nonlinear white mice was performed. It included four injections of antigen with and without adjuvant, induction of ascitic fluid accumulation through intraperitoneal inoculation of murine myeloma cells. Experimental IAFs were studied in serologic and immunologic reactions on a set of strains of R-variant Vibrio cholerae , V. cholerae nonO1/nonO139, V. cholerae O1 and heterologous microorganisms. Results and discussion. The obtained IAFs are notable for high antibody titers in indirect enzyme immunoassay (up to 1:640000), and agglutinate atypical cholera vibrios at dilutions from 1:8 to 1:32 in slide-agglutination reaction. Cross-reactions were found in the three groups of V. cholerae strains studied, indicating the presence of similar antigens. Based on the results of electrophoretic separation and immunoblotting of cell lysates of the strains, the presence of common major proteins in the region of 55–60 and 25 kDa was established. Evident differences were observed for several minor proteins in the 30–55 kDa region, in particular, they were absent in the typical strains. It is also shown that experimental IAFs contain antibodies to epitopes of the core part of LPS and surface proteins, most of them being common to the studied groups of cholera vibrios. The obtained data allow us to draw the following conclusions: the possibility of detecting a larger number of V. cholerae R-variants is increased if the ELISA kit to R-vibrios is used; the use of ELISA method is preferable to the slide-agglutination reaction for serologic analysis of atypical strains. Combining IAFs in the form of a single preparation seems promising, as it allows for characterizing the spectrum of surface antigenic determinants of altered strains and expanding the possibilities of their detection.