华东地区高致病性H5N6禽流感病毒血凝素蛋白分子特征分析

Genetic characteristic of the hemagglutinin gene of highly pathogenic H5N6 avian influenza A viruses in live-poultry market,Eastern China

目的分析2017年以来中国华东地区高致病性H5N6禽流感病毒的HA基因分子特征。方法 H5N6核酸阳性标本采用9~11日龄鸡胚进行病毒分离,病毒基因测序采用下一代测序技术,相关的参考序列下载自GISAID或NCBI网站,序列比对和进化树构建采用ClustalX、Blasts及Mega 6.1等生物信息学软件。结果 2017年以来,在江苏省活禽市场和禽流感患者的标本中,成功分离出43株H5N6禽流感病毒,对33株病毒进行了基因组测序。选择其中的27株H5N6病毒的HA基因进行分子进化分析,clade 2.3.4.4h有20株,clade 2.3.4.4e有3株,另外4株归类于clade 2.3.4.4b;多个碱性氨基酸出现在病毒HA蛋白的裂解位点,是高致病性禽流感病毒的典型分子特征;HA蛋白受体结合位点的222和224位氨基酸分别是Q和G,具有结合禽类受体α2-3半乳糖苷唾液酸(SAα2-3Gal)的特性,158位点糖基化位点丢失,但新的糖基化位点出现在124位点上。结论 2017年HA基因clade 2.3.4.4h是我国华东地区H5N6病毒优势基因型,病毒处于持续动态进化中,需要继续对病毒进化进行监测。

Objective To analyze the genetic characteristics of HA gene of highly pathogenic H5 N6 avian influenza virus in East China since 2017.Methods h5 n6 nucleic acid positive samples were isolated from 9-11 day old chicken embryos.The next generation sequencing technology was used for virus gene sequencing.The related reference sequences were downloaded from gisaid or NCBI website.The bioinformatics software clustalx,blasts and mega 6.1 were used for sequence alignment and phylogenetic tree construction.Results Since 2017,43 strains of H5 N6 avian influenza virus were successfully isolated from the samples of live poultry market and patients with avian influenza in Jiangsu Province,and 33 strains were sequenced.The HA genes of 27 strains of H5 N6 virus were selected for molecular evolution analysis.There were 20 strains of clade 2.3.4.4 h,3 strains of clade 2.3.4.4 e,and the other 4 strains were classified as clade 2.3.4.4 b;multiple basic amino acids appear in the cleavage site of HA protein,which is a typical molecular feature of highly pathogenic avian influenza virus;the amino acids at 222 and 224 of HA protein receptor binding site are Q and G,respectively,which have the characteristics of binding to avian receptorα2-3 galactoside sialic acid(SAα2-3 gal).The glycosylation site at 158 site is lost,but the new glycosylation site appears at 124 site It’s on.Conclusion clade 2.3.4.4 hof HA gene in 2017 is the dominant genotype of H5 N6 virus in East China,and the virus is in continuous dynamic evolution,so it is necessary to continue to monitor the virus evolution.