[Antigenic composition of the hemagglutinins of influenza viruses H2N2]

A comparative immunological analysis of the antigenic structure of hemagglutinins of influenza H2N2 viruses isolated in 1957-1967 was carried out by the method of specific adsorption of highly active antiviral rabbit sera. The hemagglutinins of the viruses under study were shown to contain at least three antigenic determinants changing in the course of evolution, one of them shared by all the viruses of the H2N2 subtype remaining antigenically stable since 1957 until 1967.