2014-2016年镇江地区甲型H1N1流感病毒分子进化特征研究

目的 了解镇江地区甲型H1N1流感病毒流行和变异特点。方法 收集2014-2016年镇江地区哨点医院流感样病例标本，进行核酸检测和病毒分离。在病毒流行期按月随机抽取13株甲型H1N1毒株，设计特异性的引物扩增血凝素（hemagglutinin，HA）、神经氨酸酶（neuraminidase，NA）基因，进行测序并分析其遗传进化特征。结果 13株分离株与疫苗株A/California/07/2009的HA基因核苷酸和氨基酸的同源性分别为97.3%~100.0%和96.6%~100.0%；NA基因核苷酸和氨基酸同源性分别为95.6%~97.5%和93.8%~96.6%。系统进化分析表明，13株病毒HA和NA基因分属于不同的进化谱系。分子特征表现为12株HA氨基酸序列均发生了抗原位点Sa区K173Q突变，1株同时发生了Sa区K181E突变；3株还发生了Ca1区V183I突变。受体结合位点和糖基化位点的氨基酸序列均未发生变异。结论 2014-2016年镇江地区甲型H1N1流感病毒与疫苗株相比，其HA、NA基因出现了一定程度的变异，但是抗原性并未发生改变，需进一步加强监测。

Study on molecular evolution characteristics of influenza A(H1N1)pdm09 virus in Zhenjiang from 2014 to 2016

Objective To study the epidemiological characteristics and variation of the influenza A(H1N1)pdm09 virus. Methods The throat swabs were collected from patients with influenza-like illness(ILI) in sentinel surveillance hospital in Zhenjiang from 2014 to 2016. These throat swabs were collected for influenza virus RNA detection and isolation. 13 strains of A(H1N1)pdm09 virus were randomly selected in the epidemic period,then specific primers were designed to sequence the hemagglutinin (HA) and neuraminidase (NA) genes and the genetic characterization of these 13 isolates were analyzed. Results Compared to the vaccine strain A/California/07/2009, the 13 isolated strains shared high nucleic acid sequence similarity in HA and NA genes(97.3%-100.0% and 95.6%-97.5%, respectively), and high amino acid sequence similarity (96.6%-100.0% and 93.8%-96.6%, respectively). The phylogenetic analysis showed that the HA and NA genes of 13 isolated strains were divided into different evolutionary lineages. The molecular characteristics indicated at Sa antigenic site in HA1 domain, 12 isolates had mutations of K173Q,while one had the mutation of K181E. At Ca1 antigenic site in HA1 domain, three isolates had mutations of V183I. Sequence analysis indicated there was no mutation in the receptor binding sites and glycosylation sites. Conclusions Though the HA and NA genes of 13 isolated showed varying degrees of genetic variation compared those of vaccine strain,the antigenicity characteristic remained unchanged. The further monitoring for influenza virus in Zhenjiang is very necessary.