title: Genetic stability of cold-adapted A/Leningrad/134/47/57 (H2N2) influenza virus: sequence analysis of live cold-adapted reassortant vaccine strains before and after replication in children.
abstract: We previously reported that the A/Leningrad/134/47/57 (H2N2) cold-adapted virus (A/Len/47) used in preparing reassortant live attenuated vaccines for children acquired 14 (11 coding) mutations in genes coding for proteins other than haemagglutinin and neuraminidase during cold-adaptation. Preservation of these mutations in genomes of viruses isolated from children on the second, fifth, or eighth day after vaccination was examined by sequence analysis. The sequence data demonstrated that all nine coding mutations selected for examination were conserved in the genomes of all 11 strains investigated, indicating that the mutations accompanying cold-adaptation and attenuation of the A/Len/47 master vaccine are highly stable.
authors.affiliation: Influenza Branch G-16, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
authors.forename: A I
authors.initials: AI
authors.lastname: Klimov
authors.forename: A Y
authors.initials: AY
authors.lastname: Egorov
authors.forename: M I
authors.initials: MI
authors.lastname: Gushchina
authors.forename: T E
authors.initials: TE
authors.lastname: Medvedeva
authors.forename: W C
authors.initials: WC
authors.lastname: Gamble
authors.forename: L G
authors.initials: LG
authors.lastname: Rudenko
authors.forename: G I
authors.initials: GI
authors.lastname: Alexandrova
authors.forename: N J
authors.initials: NJ
authors.lastname: Cox
mesh_terms: D000064:Acclimatization; D000595:Amino Acid Sequence; D001483:Base Sequence; D002648:Child; D003062:Codon; D003080:Cold Temperature; D017124:Conserved Sequence; D017931:DNA Primers; D016679:Genome, Viral; D006801:Humans; D053121:Influenza A Virus, H2N2 Subtype; D009980:Influenza A virus / Q000235:genetics* / Q000276:immunology / Q000502:physiology*; D007252:Influenza Vaccines; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012426:Russia; D014613:Vaccines, Attenuated; D014779:Virus Replication
chemical_list: D003062:Codon; D017931:DNA Primers; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated