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

Abstract

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.

Origin and evolutionary characteristics of antigenic reassortant influenza A (H1N2) viruses isolated from man in China

“…These nucleotide sequences were determined in this study. Sequences published previously are: PB2, CHL83 (Schrier et al, 1988) and NT68 (Jones et aL, 1983); PB1, WI88 (Kawaoka et at., 1989), AA60 (Cox et al, 1988) and NT68 (Bishop et al, 1982a); PA, AAG0 (Cox et al, 1988) and NT68 (Bishop et aL, 1982b); HA, YA86 (Yamada et al, 1991), NT68 (Both & Sleigh, 1980), VIC75 (Min et al, 1980) and BK79 (Both & Sleigh, 1981); NP, AA60 (Cox et al, 1988), NT68 (Huddleston & Brownlee, 1982) and UDO72 (Buckler-White & Murphy, 1986); NA, NT68 (Bentley&Brownlee, 1982), UDO72 (Markoff& Lai, 1982), VIC75 (Rompuy et al, 1982) and BK79 (Martinez et al, 1983); M, AAG0 (Cox et al, 1988), UDO72 (Lamb et aL, 1981) and BK79 ; NS, USSR77 (Buonagurio et al, 1986), CHL83 (Schreier et al, 1989), AAG0 (Buonagurio et al, 1986) and UDO72 (Lamb & Lai, 1980). § HK, Hong Kong virus isolates.…”

Influenza A virus haemagglutinin polymorphism: pleiotropic antigenic variants of A/Shanghai/11/87 (H3N2) virus selected as high yield reassortants

“…RNA sequencing. RNA sequence analysis was performed by the dideoxynucleotide chain termination method, using synthetic oligodeoxynucleotide primers and reverse transcriptase essentially as described elsewhere (Cox et al, 1988) except that 10 gCi of [aSS]dATP (Amersham; specific activity > 1000Ci/mmol) for each 5.5 ~tl of reaction mixtures was used and reverse transcriptase incubations and chase were done at 42 °C for 20 min. The HA1 domains of the HA genes of the X-99aE and Sh/ly (low yield) viruses (Table 1) were amplified by the PCR method (Saiki et al, 1988;X.…”

Molecular studies of influenza B virus in the reverse genetics era

“…The importance of mutations in the M1 protein of the att phenotype is of interest. In the equivalent influenza A viruses developed as live attenuated vaccine backbones, analysis revealed that the phenotypes were mediated by mutations in the polymerase genes (Cox et al, 1988;Snyder et al, 1988) and although the M gene has previously been implicated in conferring the att phenotype (Snyder et al, 1988), mutations in the M1 protein did not play a role in the attenuation (Cox et al, 1988;Sweet et al, 2004). This suggested a different mode of attenuation for the influenza A and influenza B virus vaccine backbones.…”