Nonimmunoselected intrastrain genetic variation detected in pairs of high-yielding influenza A (H3N2) vaccine and parental viruses

J Infect Dis. 1994 Dec;170(6):1432-8. doi: 10.1093/infdis/170.6.1432.


Seven influenza A (H3N2) high-yielding vaccine candidate strains were examined. Antigenic analysis revealed that 5 of the strains could be distinguished antigenically from their corresponding wild type parent viruses. Comparative sequence data for the HA1 domains of the HA (hemagglutinin) genes for these 5 high-yielding viruses and the corresponding wild type parents demonstrated one to three amino acid substitutions within each virus pair, with at least one amino acid change being located in a previously defined antigenic site. Comparison of the HA sequences of the 2 antigenically indistinguishable virus pairs revealed no amino acid differences in 1 and one amino acid change in the other. Examination of 1 additional wild type virus, A/Guangdong/39/89, and its three high-yielding derivatives obtained either by serial egg passage or by reassortment revealed an additive effect of the HA and M genes in creating the high-yielding phenotype.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Genes, Viral / genetics*
  • Genetic Variation / genetics*
  • Hemagglutination Inhibition Tests
  • Hemagglutinin Glycoproteins, Influenza Virus
  • Hemagglutinins, Viral / genetics*
  • Humans
  • Influenza A Virus, H3N2 Subtype*
  • Influenza A virus / genetics*
  • Influenza Vaccines / genetics
  • Molecular Sequence Data
  • RNA, Viral / genetics
  • Reassortant Viruses / genetics*
  • Sequence Analysis, DNA
  • Viral Structural Proteins / genetics*


  • Hemagglutinin Glycoproteins, Influenza Virus
  • Hemagglutinins, Viral
  • Influenza Vaccines
  • RNA, Viral
  • Viral Structural Proteins

Associated data

  • GENBANK/L18994
  • GENBANK/L18995
  • GENBANK/L18996
  • GENBANK/L18997
  • GENBANK/L18998
  • GENBANK/L18999
  • GENBANK/L19000
  • GENBANK/L19001
  • GENBANK/L19002
  • GENBANK/L19003
  • GENBANK/L19004