[Antigenic determinants in the composition of the hemagglutinins of the influenza virus H1N1 isolated in 1977 and of the H1N1 viruses isolated in 1947--1956].

A comparative analysis of hemagglutinins (HA) of the A/USSR/090/77 (H1N1) virus isolated in 1977 and A/FM/47, A/Leningrad/49, A/Pan/52, and A/Netherlands/56 viruses with the antigenic formula (H1N1) was done. By the method of cross adsorption of rabbit influenza antisera, HA of the viruses under study were found to contain three antigenic determinants: one is common for all the variants studied, another characterizes the relationships of individual variants isolated in different years, and the third is strain-specific, determining the antigenic differences between the variants. According to our results, the influenza A/USSR/090/77 (H1N1) virus has in its HA three antigenic determinants closely related or identical to those of HA of a/leningrad/49 and A/Pan/52 viruses.