[Antigenic drift of epidemic strains of influenza A virus (H3N2) in 1985].

The study included 230 strains of influenza A (H3N2) virus isolated in the epidemic of 1985. A high degree of heterogeneity of the virus population was established with polyclonal sera, monoclonal antibodies and the method of kRNA-bRNA hybridization for the determination of the genome composition. Among the strains of one epidemic (1985) three antigenically heterogenous groups of strains were detected similar with reference A/Philippines/2/82, A/Ken/1/84, and A/Mississippi/1/85 strains. It was shown that in the process of antigenic drift in some strains there occurred a reversion of the antigenic determinants similar to those of previously circulating epidemic A/Texas/1/77 strain.