Identification of sequence changes in the cold-adapted, live attenuated influenza vaccine strain, A/Ann Arbor/6/60 (H2N2)

Virology. 1988 Dec;167(2):554-67.


Nucleotide sequences have been obtained for RNA segments encoding the PB2, PB1, PA, NP, M1, M2, NS1, and NS2 proteins of the influenza A/Ann Arbor/6/60 (H2N2) wild-type (wt) virus and its cold-adapted (ca) derivative that has been used for preparing investigational live attenuated vaccines. Twenty-four nucleotide differences between the ca and wt viruses were detected, of which 11 were deduced to code for amino acid substitutions in the ca virus proteins. One amino acid substitution each was predicted for the PB2, M2, and NS1 proteins. Two amino acid substitutions were predicted for the NP and the PA proteins. Four substitutions were predicted for the PB1 protein. The biological significance of mutations in the PB2, PB1, PA, and M2 genes of the ca virus is suggested by currently available genetic data, a comparison with other available influenza gene sequences, and the nature of the predicted amino acid changes. In addition, the sequence data confirm the close evolutionary relationship between the genomes of influenza A (H2N2) and influenza A (H3N2) viruses.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Capsid / genetics
  • Cold Temperature
  • DNA-Directed RNA Polymerases / genetics
  • Genes, Viral
  • Influenza A Virus, H2N2 Subtype*
  • Influenza A virus / genetics*
  • Influenza Vaccines / genetics*
  • Molecular Sequence Data
  • RNA, Messenger / genetics
  • RNA, Viral / genetics
  • Ribonucleoproteins / genetics
  • Vaccines, Attenuated / genetics*
  • Viral Core Proteins / genetics
  • Viral Matrix Proteins / genetics
  • Viral Nonstructural Proteins
  • Viral Proteins / genetics


  • Influenza Vaccines
  • RNA, Messenger
  • RNA, Viral
  • Ribonucleoproteins
  • Vaccines, Attenuated
  • Viral Core Proteins
  • Viral Matrix Proteins
  • Viral Nonstructural Proteins
  • Viral Proteins
  • DNA-Directed RNA Polymerases