antigenic variants of influenza a/hong kong/1/68 ( h3n2 ) were obtained in vitro by letting virus multiply in the allantosis-on-shell system in the presence of anti-haemagglutinin antibodies , prepared from immune goat serum to purified haemagglutinin antigen , and in vivo by giving mice antibody intraperitoneally one day before challenge with a sublethal dose of live virus .
C0020960
immune
C0003241
antibody