THE INEFFECTIVENESS OF BCG TO PROTECT AGAINST TUBERCULOSIS INFECTION IN MICE OF B10.M LINE (H2F) AND THE IMMUNE RESPONSE TO MYCOBACTERIAL ANTIGENS

Objective: to identify specific features of the immune response making BCG vaccine ineffective in mice carrying H2 f allele of the main complex of tissue compatibility. Subjects and methods . Inbred lines of B10.M (H2 f ) and B10 (H2 b ) mice vaccinated and not vaccinated with BCG and infected with M. tuberculosis H 37 Rv, were compared in terms of survival after the infection, the number of mycobacteria in the lungs, the ability of T-lymphocytes to recognize mycobacterial antigens and produce interferon- γ (IFN- γ ) in response to mycobacterial antigens and non-specific stimulation of T-receptors. Results. It was found out that B10.M mice were unable to produce T-cells by the lymphoid organs (spleen) and lungs to produce IFN- γ in response to long-term stimulation of mycobacterial antigens in chronic infection, although the recognition of these antigens, as well as the ability to produce IFN- γ in response to non-specific binding of T-receptors with anti-CD3 antibodies, were completely preserved. It was demonstrated that the defect in IFN- γ production manifested at a late stage of infection regardless of prior BCG vaccination, and hypothesized that it was rather associated with the phenomenon of specific "immunological depletion" of T-cells in mice carrying some allelic variants of H2 complex.