2010年南京人群甲型H3N2流感分离毒株全基因组特性分析

Analysis on genomic characteristics of H3N2 subtype influenza A virus isolated in Nanjing,2010

目的分析2010年南京地区甲型H3N2流感病毒的分子特征和演化趋势。方法测定2010年期间所分离3株病毒的8个RNA片段的核苷酸序列。构建各个基因基于核苷酸序列的系统发生树,并分析分离毒株与参考毒株11个基因特定氨基酸位点的变异情况。结果在3株病毒中,未发生片段间的重配。以A/Perth/16/2009为参考,3个分离毒株发生在HA和NA蛋白抗原决定簇的氨基酸变异均数分别为5.7和1.3;以A/Brisbane/10/2007为参考,3株病毒PB1的第375位发生突变(S→G),Nanjing/1655和Nanjing/1663的PB1-F2蛋白第26位缺失。另外3株病毒M2的金刚烷胺耐药位点(31位)为N。结论所测3株流感病毒HA基因的氨基酸变异可能导致新流行株的形成,病毒对金刚烷胺耐受而对神经氨酸酶抑制剂敏感。病毒的PB1第375位和PB1-F2第26位的变异可能成为H3N2病毒新的进化方向。

The molecular characteristics and evolutionary features of H3N2 subtype influenza A viruses in 2010 were to be determined. Eight RNA segments of 3 virus were sequenced. The phylogenetie trees were constructed for analysis of evolu- tionary characteristics, and variations of important amino acid sites of all eleven kinds of protein were analyzed. No reassort- ment was observed in our isolates. Compared with isolate A/Perth/16/2009, average variations number of amino acid site of HA and NA protein antigenic determinants were 5.7 and 1.3 respectively. Compared with isolate A/brisheme 10/2997, the a- mino-acid position 375 of PB1 protein in all isolates had varied （S→G） and position 25 of PB1-F2 protein in both Nanjing/1655 and Nanjing/1663 were deleted. In addition, position 31 of M2 protein in all three isolates were N, which was considered as one bio-marker of amantadine resistance. In conclusion the amino acid site variations in HA antigenic determinants of three H3N2 isolates probably result in emergence of new epidemic influenza strains. All three isolates were tolerable to amantadine but susceptible to NA inhibitors. What＇s more, variations of PB1 （position 375） and PB1-F2 （position 25） might represent the future evolutionary direction of H3N2 viruses.