Studies on the origin of pandemic influenza. I. Antigenic analysis of A 2 influenza viruses isolated before and after the appearance of Hong Kong influenza using antisera to the isolated hemagglutinin subunits.

Animals Antigens/analysis Antigens, Viral/analysis Chick Embryo Cross Reactions Disease Outbreaks/microbiology Epitopes Erythrocytes/immunology Genetics, Microbial Hemagglutination Inhibition Tests Hemagglutination Tests Hemagglutinins, Viral/analysis,isolation & purification Hong Kong Humans Immune Sera Immunodiffusion Influenza, Human/microbiology Neuraminidase/analysis Orthomyxoviridae/enzymology,immunology Rabbits/immunology Recombination, Genetic Species Specificity Virus Cultivation

Antigens Antigens, Viral Epitopes Hemagglutinins, Viral Immune Sera Neuraminidase