2016-2024年湖北省麻疹病毒流行株血凝素基因特征

Characteristics of hemagglutinin genes of measles viruses circulating or observed in Hubei province from 2016 to 2024

目的分析湖北省麻疹病毒(Measles virus,MV)流行株血凝素(Hemagglutinin,H)基因特征。方法收集2016-2024年湖北省麻疹病例咽拭子MV核酸阳性标本,进行MV分离培养和H基因序列扩增,构建MV的H基因序列系统进化树,分析核苷酸同源性和氨基酸变异。结果共获得32株MV分离株,其中2016-2018年H1a基因型25株、2019年B3基因型3株、2021-2024年A基因型(疫苗株)4株,各基因型分离株的H基因核苷酸同源性分别为99.4%-100%、100%、99.8%-100%,与中国疫苗株S-191相比的同源性分别为94.6%-94.9%、96.1%、99.6%;2016-2019年MV分离株H蛋白存在L131F、R243G、Y481N、N484T和D506G共同氨基酸变异,在238-240位区域缺少1个N-糖基化位点,在主要表位上发生N178T、G211S、S240N、P397L、A400V、H448R、K460R和G546S变异。结论2016-2024年湖北省优势基因型MV流行株从H1a和B3基因型转变为A基因型,分离株H蛋白多个抗原表位发生氨基酸变异。

Objective To analyze characteristics of hemagglutinin(H)genes of measles viruses(MV)circulating or observed in Hubei province.Methods We collected throat swab samples in Hubei from 2016 to 2024 that were positive to MV nucleic acid for MV isolation and H gene sequence amplification.We constructed a phylogenetic tree of MV H gene sequences and determined nucleotide homology and amino acid variations.Results A total of 32 MV strains were isolated,including 25 strains of H1a genotype from 2016 to 2018,3 strains of B3 genotype from 2019,and 4 strains of A genotype(vaccine strains)from 2021 to 2024.Nucleotide homologies of H genes within the three genotypes were 99.4%-100%,100%,and 99.8%-100%,respectively.Compared with the vaccine strain S-191,nucleotide homologies of H genes for the three genotypes were 94.6%-94.9%,96.1%,and 99.6%.Five common amino acid variation of L131F,R243G,Y481N,N484T,and D506G were identified in H proteins of MV isolates from 2016 to 2019,with one N-glycosylation site in the 238-240 regions missing.Variations of N178T,G211S,S240N,P397L,A400V,H448R,K460R,and G546S occurred at major epitopes of H proteins.Conclusion Dominant genotypes of MV circulating or observed in Hubei during 2016-2024 changed from H1a and B3 genotypes to A genotype,and amino acid variations occurred at multiple antigen epitopes of H proteins.