title: Antigenicity and evolution amongst recent influenza viruses of H1N1 subtype.
abstract: The sequence of the HA1 subunit region of the haemagglutinin gene of influenza A/USSR/90/77, and A/Brazil/11/78, A/Lackland/3/78, A/England/333/80 and A/India/6263/80 was determined by dideoxy-sequencing methods using total virion RNA and specific oligonucleotide primers for reverse transcriptase. These 1977-1980 strains share a minimum of 85% amino acid sequence homology with influenza A/PR/8/34. Most of the surface amino acid substitutions which occurred during the evolution of A/PR/8/34 to A/USSR/90/77 and subsequently in the 1978-1980 strains are located in the 4 antigenic sites previously defined by an analysis of laboratory-selected mutants of A/PR/8/34. We deduce an evolutionary pathway for the 1977-80 strains and suggest their different epidemic properties may be a consequence of only a few amino acid changes.
mesh_terms: D000956:Antigens, Viral / Q000235:genetics*; D001483:Base Sequence; D005075:Biological Evolution; D006387:Hemagglutination, Viral; D006389:Hemagglutinins, Viral / Q000235:genetics*; D053118:Influenza A Virus, H1N1 Subtype; D009980:Influenza A virus / Q000235:genetics / Q000276:immunology*; D012367:RNA, Viral / Q000235:genetics; D013045:Species Specificity; D014771:Virion / Q000235:genetics
chemical_list: D000956:Antigens, Viral; D006389:Hemagglutinins, Viral; D012367:RNA, Viral