title: Nucleotide sequences of the neuraminidase genes of influenza A/Leningrad/134/57 (H2N2) virus and two of its live, attenuated, cold-adapted variants.
abstract: The nucleotide sequences of the neuraminidase (NA) genes of the A/Leningrad/134/57 (H2N2) wild-type (Len/wt) virus as well as two of its live attenuated, cold-adapted (ca) variants, A/Leningrad/134/17/57 (Len/17) and A/Leningrad/134/47/57 (Len/47), were determined. In comparison with Len/wt, one nucleotide change (C-225 to A) was found in the NA gene of Len/17. This change codes for a Thr-to-Asn substitution at position 69 of NA. The NA gene of the more attenuated Len/47 ca virus has one silent (T-814 to C) and two coding nucleotide substitutions, C-78 to T (Ala-20 to Val) and C-225 to A (Thr-69 to Asn). These sequence data were used to design a PCR-restriction technique to determine the origin of the NA gene in candidate live, attenuated vaccine reassortants made by reassorting these ca strains with current field viruses.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004279:DNA, Viral; D014644:Genetic Variation; D006801:Humans; D053121:Influenza A Virus, H2N2 Subtype; D009980:Influenza A virus / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D009439:Neuraminidase / Q000235:genetics*; D016865:Reassortant Viruses / Q000235:genetics
chemical_list: D004279:DNA, Viral; D009439:Neuraminidase