[Evaluation of the effectiveness of group-A and -C meningococcal polysaccharide vaccines by molecular parameters]. / Otsenka éffektivnosti meningokokkovykh polisakharidnykh vaktsin grupp A i C po molekuliarnym parametram.

Chromatographic properties of meningococcal polysaccharides and vaccines of serogroups A and C prepared at the G. N. Gabrichevskii Moscow Research Institute of Epidemiology and Microbiology were studied during determination of their molecular parameters by gel filtration on sepharose 4B. It was shown that the character of the polysaccharide elution was not affected by the composition of the eluent and pH changes within the ranges of 6.5-8.5. The ionic strength of the solvent should be at least 0.2 mol/l. Immunochemical methods such as countercurrent and rocket immunoelectrophoresis were standardized and recommended for quantitative evaluation of the content of meningococcal polysaccharides of groups A and C in the eluates. Rocket immunoelectrophoresis was shown to be more accurate and reproducible.

[Isolation and characteristics of a specific polysaccharide of group-B meningococci]. / Vydelenie i kharakteristika spetsificheskogo polisakharida meningokokkov gruppy B.

The optimum conditions for the isolation and purification of the specific polysaccharide of group B meningococci have been developed. The advantages of the use of synthetic culture media for growing the initial bacterial culture have been demonstrated. The purified polysaccharides have been found to contain about 70% of sialic acid and less than 1% of protein and nucleic acid admixtures. The molecular parameters of group B polysaccharide depended on the growth phase of the bacterial culture. The most valuable culture was obtained at the exponential phase of growth. High serological activity and specificity of the polysaccharide in the passive hemagglutination test recommend it for studies on the development of diagnostic and prophylactic preparations.

[Immunologic properties of purified and complex preparations of group-B meningococcal polysaccharide]. / Immunologicheskie svoistva ochishchennykh i kompleksnykh preparatov polisakharida meningokokkov gruppy B.

The complex preparations of group B meningococcal polysaccharide have been found to be capable of inducing primary immune response in mice, while purified group B polysaccharide has proved to be immunologically inert. As revealed in this investigation, the intravenous injection to mice of the optimum doses of the complex preparation of group B polysaccharide leads to the increased number of specific B-antibody-forming cells in their spleens and to a rise in B-antibody titers in their sera; besides, the time course of the process has been studied. Both preparations have been found capable of forming the immunological memory in mice if booster immunization is made with the complex preparation of group B polysaccharide. The immunological inertness of purified group B polysaccharide is attributed, supposedly, to the action of some specific suppressor mechanism. Considering the pronounced antigenic activity of the complex preparation of group B polysaccharide and the insignificant admixture of endotoxin in this preparation, the suitability of its future use as vaccine for the prophylaxis of meningitis caused by group B meningococcus is indicated and the tentative immunization schedules are discussed.