淮安市H3N2亚型流感病毒全基因组序列的遗传特征分析

Sequence analysis of whole genome of influenza A(H3N2)virus in Huai′an

目的了解江苏省淮安市H3N2亚型流感病毒的生物学特性和变异情况,为流感疫情防控与疫苗研发提供参考依据。方法选取4株2022年淮安市流感监测网络实验室分离的流感毒株,通过全基因组核酸提取、文库构建,应用Nanopore三代测序平台对H3N2亚型毒株进行全基因组序列测定,利用生物信息学软件比对基因组序列相似性、构建系统发育树,解析氨基酸变异特征。结果8个基因节段之间的核苷酸相似性为97.1%~100.0%,相似性差异最大的是HA基因(97.1%~99.9%),差异最小的是MP基因(98.6%~99.9%)。核苷酸位点变异频率最高和最低的节段分别是HA基因(3.06%)和MP基因(1.43%),不同基因节段核苷酸变异率有统计学意义(χ^(2)=14.293,P=0.046)。HA和NA基因发育树拓扑结构基本一致,3株隶属3C.2a1b.2a.1a进化簇,1株独立属于3C.2a1b.1b进化分支且糖基化位点相较于另外3株在HA1蛋白142NWT、149NGT和NA蛋白436NLS位点发生丢失。4株淮安株均对NA抑制剂和金刚烷胺类药物敏感。结论1株淮安株抗原性发生了改变,与当年疫苗株匹配性较低,建议持续加强H3N2流感病毒的基因监测,为流感防控及流感疫苗筛选提供科学依据。

Objective To study the biological traits and mutations of the influenza A(H3N2)virus in order to produce a vaccine and offer references for controlling and preventing influenza epidemics.Methods Four strains of the influenza A(H3N2)virus were chosen from the Huai′an surveillance network laboratory.Nucleic acid extraction,library building,and sequencing(CridION x5 MKI Nanopore)were used to produce the whole-genome sequences.Using homologous alignments of whole-genome sequences,phylogenetic tree construction,and amino acid variant screening,bioinformatics analysis was carried out.Results The nucleotide identity between 8 gene segments ranged from 97.1%to 100.0%.The gene that differed the most from the reference sequences was HA(97.1%-99.9%),and the gene that differed the least was MP(98.6%-99.9%).The HA gene(3.06%)and MP gene(1.43%)were the regions with the greatest and lowest frequencies of nucleotide site change,respectively.The rates of nucleotide change varied significantly between the genes(χ^(2)=14.293,P=0.046).Four influenza A(H3N2)virus strains′whole-genome phylogenies from each of the eight gene segments maintained a roughly consistent topological structure.One strain was linked to the 3C.2a1b.1b clade,which was lost at the 142NWT,149NGT(HA1),and 436NLS(NA).Three strains were linked to the 3C.2a1b.2a.1a clade lineage.Amantadine and NA inhibitors were effective against all Huai′an strains.Conclusions The antigenicity of one strain of Huai'an strain changed and its matching with the vaccine strain of that year was low.It is suggested that the genetic surveillance of H3N2 influenza virus should be continuously strengthened to provide scientific basis for influenza prevention and control and influenza vaccine screening.