[Features of immunogenesis in simians infected with attenuated strains of tick-borne encephalitis and Langat virus].

Certain parameters of humoral and cellular immunity induced by attenuated tick-borne encephalitis (TBE) and Langat virus strains were studied in monkeys. The immunogenic activity of the strains inoculated subcutaneously and intracerebrally was manifested by two processes: synthesis of specific antibody and cellular immune response. The highest titers of humoral immunity in N, HI, and CF tests were observed to homologous viruses. The immune response to both homologous and heterologous viruses could be optimized by increasing the number of antigenic stimulations. The sequence of antibody synthesis of the macro- and microglobulin series was similar in monkeys infected with virulent and attenuated strains. Cellular immunity reactions were detected and changes in the quantity and functional activity of T- and B-lymphocytes were determined. Most marked immunological changes were observed with the virulent TBE virus strain as compared with naturally and experimentally attenuated Langat virus strains.