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Aim: To study effect of recombinant heat-shock protein (rHSP70) of Mycobacterium tuberculosis on immunogenicity of Haemophilus influenzae type b capsular polysaccharide (CPSHib)., Materials and Methods: Capsular polysaccharide was obtained by precipitation with cetavlon, antibody titers and Toll-like receptors (TLRs) were detected by enzyme immunoassay and flow cytometry respectively., Results: rHSP70 modified immune response to chemically conjugated and unconjugated CPSHib. rHSP70 enhanced expression of TLRs 2, 4, 9 on mice splenocytes; increased levels of CD3+, CD8+, NK, CD3/NK (NKT) lymphocytes. Levels of CD4+, CD25+ (markers of early activation of T-helpers) as well as MHC class II molecules were increased that could be appraised as a shift from T-independent to T-dependent immune response. Difference in antibody titers after 2- or 3-dose immunization of mice with 5 mcg/dose of CPSHib in mixture or conjugated with rHSP70 was not revealed. Level of antibodies to rHSP70 in serum samples of mice immunized with CPSHib conjugated with rHSP70 was 6.55 - 8.4 times higher compared to unimmunized animals. Antibodies, which have common antigenic epitopes to human organs and tissues, were not detected., Conclusion: rHSP70 modifies immune response to CPSHib.

Test-system using index of phagocytosis of noncapsulated mutant loaded by one of the several capsular antigenic complexes was developed and used for screening for both immunogenic and protective capsular antigens of B. mallei. Direct correlation between index of phagocytosis, level of delayed-type hypersensivity, and protective effect of capsular antigens has been shown on the model of experimental melioidosis in susceptible white mice, guinea pigs and white rats. Obtained results let to use the developed test-system for initial selection of B. mallei protective capsular antigens and their further study as potential components of preparations for specific prophylaxis of glanders and melioidosis.