浙江省宁波市2014～2015年H3N2流行性感冒病毒HA1基因与NA基因特性分析

Genetic Analysis of HA1 and NA Regions of Influenza Virus Subtype A3 Isolates in Ningbo City of Zhejiang Province

目的分析2014~2015年宁波市H3N2流行性感冒（流感）的流行特征和流行株血凝素（HA）基因和神经氨酸酶（NA）基因的变异情况。方法选择宁波市2014~2015年流感流行期间分离的H3N2代表株17株,进行HA1基因和NA基因扩增、测定,用DNAstar的Meg Align序列分析软件进行分析处理。结果宁波市2014~2015年H3N2流感毒株HA1基因的核苷酸长度均为987 bp,编码329个氨基酸;NA基因的核苷酸长度均为1 410 bp,编码469个氨基酸。2014年H3N2流感病毒HA1基因与2015年相比该区域有10~12个氨基酸位点存在差异,其中有5个氨基酸位点涉及HA1区3个抗原决定簇,在158~160位氨基酸上增加了一个糖基化位点;NA基因发生了6~8个氨基酸位点的替换,2015年与2014年相比在245~247位增加了一个糖基化位点。在基因进化树上2014年与2015年的流行株也都形成了独立的分支。结论宁波市2014~2015年间H3N2流感病毒无论是HA1基因还是NA基因均产生了较大的变异,流感病毒的流行应与病毒的抗原性漂移有关。

Objective To study genetic mutations at HA and NA regions of influenza virus subtype A3 isolates of Ningbo during 2014 to 2015.Methods RNA of 17 influenza virus subtype A3 isolates that circulated in Ningbo during 2014 to 2015 was extracted.HA1 and NA regions were amplified and sequenced.The sequence data were analyzed using the DNAstar software.Results HA1 and NA regions of al1 isolates belonged to 987 bp and 1 410 bp,encoding proteins of 329 and 469 amino acids,respectively.Compared with isolates in 2014,10-12 amino acids at the HA1 region of isolates in 2015 were substituted,5 of which involved 3 antigenic determinant sites,and 6-8 amino acids at the NA region were substituted.Influenza virus subtype A3 isolates in 2015 had one more glycosylation site at 158-160 sites of the HA1 region and at 245-247 sites of the NA region,respectively.Isolates in 2014 and in 2015 were different branches.Conclusions Significant mutations at the HA1 or NA region were observed in isolates during 2014-2015.There was a correlation between antigenic drift of influenza virus subtype A3 and epidemics in Ningbo.