[Antigenic structure of hemagglutinins of influenza H1N1 (Hsw1N1) virus isolated from humans and ducks].

The method of specific adsorption followed by the use of antisera in HI test and competitive enzyme immunoassay was used to study the antigenic composition of hemagglutinins (HA) Hsw1 in influenza viruses isolated in 1982 from humans in Bulgaria and in 1976 in Canada from ducks as well as their antigenic relationships with HA of Hsw1 variant isolated from swine and man. Hemagglutinins of Hsw1 strains isolated from man in Bulgaria and Alma-Ata were found to be similar to HA of A/New Jersey/8/76 virus in two determinants and with hemagglutinin of the classic virus of swine in three determinants. The HA of A/duck/Alberta/35/76 virus was similar in three determinants to HA of A/New Jersey/8/76 virus and in two determinants with other Hsw1 variants. The similarities and differences in antigenic determinants of HA in Hsw1 viruses isolated from man and animals attest to their common origin and different modes of variability.