title: Immunological studies with the HA1 and HA2 polypeptides of influenza A virus haemagglutinin.
abstract: HA1 and HA2 polypeptides of influenza A virus haemagglutinin (HA) were separated in purified form using electrophoresis in SDS containing polyacrylamide gels (PAGE) or chloroform-methanol extraction. The populations of HA1 polypeptides were immunogenic but considerably less so than the intact HA molecule and induced antibody which cross-reacted with influenza A and B viruses. After absorption with heterologous influenza B virus, the cross-reacting antibodies were removed and the HA1 antisera then possessed antibodies which reacted only with the cross-reactive (CR) determinants of the HA of the homologous influenza A virus and viruses of the same subtype. Neither strain-specific (SS) nor virus-neutralizing antibodies were detected in these anti-HA1 sera. HA2 polypeptides were less immunogenic and anti-HA2 antisera after absorption with influenza B virus failed to react with influenza A virus in immuno double diffusion tests and only reacted with partially denatured HA in the more sensitive single radial diffusion tests.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000956:Antigens, Viral; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes; D006389:Hemagglutinins, Viral / Q000276:immunology* / Q000302:isolation & purification; D005779:Immunodiffusion; D009980:Influenza A virus / Q000276:immunology*; D010455:Peptides / Q000276:immunology*; D011817:Rabbits
chemical_list: D000956:Antigens, Viral; D000939:Epitopes; D006389:Hemagglutinins, Viral; D010455:Peptides