[Isolation of strain-specific and cross-reacting antibodies to influenza virus hemagglutinins from heterogenous populations of hyperimmune influenza sera].

A population of monoreceptor cross-reacting antibodies to a common antigenic determinant H1.1 present on the surface of hemagglutinin molecules of H0, H1 and Hsw1 subtypes has been isolated from a heterogenous population of antihemagglutinating antibodies of influenza hyperimmune sera. Selective adsorption yields highly active strain-specific sera to HA of A/FM/1/47 and A/Netherlands/36/56 viruses. Populations of strain-specific antibodies to HA of A/Moscow/Pan/52 and A/USSR/090/77 viruses were found to be identical, attesting to the complete similarity of the antigenic composition of HA of these viruses. The hyperimmune serum of A/Brazil/11/78 virus was found to contain a population of strain-specific antibodies different from HA of other H1N1 viruses studied. This shows that drift variants of A/USSR/090/77 virus appeared in 1978.