目的 分析2009-2012年湖州市甲3亚型流感病毒主要抗原基因血凝素(HA)和神经氨酸酶(NA)的分子变异特征。 方法 选择浙江省湖州市2009-2012年流感流行期间分离的甲3亚型代表株11株,提取病毒RNA,扩增HA1和NA基因,进行序列测定,用MegAlign软件分析处理。 结果 湖州市近几年甲3亚型流感流行株在HA1区的核苷酸长度均为987 bp,编码329个氨基酸;在NA区的核苷酸长度为1362 bp,编码454个氨基酸。2009-2012年甲3亚型流感病毒分离株HA1区与NA区的氨基酸同源性分别在94.7%～99.9%与96.2%～100.0%之间,HA1区的变异较NA区更大。4个流感流行期分离的甲3亚型流感毒株相比HA和NA发生了多个氨基酸位点的替换。此外,近几年来世界卫生组织推荐的甲3亚型流感疫苗株与当年的流感流行株之间存在一定的差异。 结论 2009-2012年湖州市甲3亚型流感病毒流行株发生明显变异,基因重配和抗原漂移是病毒发生变异的主要机制。
Objective To understand the genetic variation of hemagglutinin(HA) and neuraminidase(NA) of influenza A3 virus circulated in Huzhou during 2009-2012. Methods The RNA of 11 influenza A3 virus strains, circulated in Huzhou during this period, were extracted. The HA1 and NA regions were amplified and sequenced. All the sequence data were analyzed using MegAlign. Results The HA1 and NA regions of all strains belonged to 987nt and 1362nt, encoding protein of 329 and 454 amino acids respectively. The strains shared amino acid homology of 94.7%-99.9% and 96.2%-100.0% in HA1 and NA regions respectively, the variation in HA1 region was greater than that in NA region. Multi amino acid loci variation had occurred compared with the influenza A3 virus strains isolated in previous years. In addition, there were some differences between the vaccine strains recommended by WHO and the circulated strains. Conclusion Obvious genetic variation had occurred among the strains of influenza A3 virus isolated in Huzhou from 2009 to 2012. Genetic reassortment and antigenic drift seemed to be the major evolutionary mechanism of influenza A3 virus.