2016年盐城地区麻疹病毒分子分型及血凝素蛋白基因特征分析

Molecular genotyping of measles viruses in Yancheng area in 2016 and analysis of the genetic characterization of hemagglutinin genes

目的 鉴定2016年流行于盐城地区的麻疹野病毒的基因型别,并对血凝素蛋白基因进行分子进化特征分析.方法 通过实时荧光RT-PCR方法对2016年盐城市疑似麻疹病例咽拭子标本进行核酸检测,对麻疹病毒核酸阳性标本RT-PCR扩增核蛋白、血凝素蛋白基因并测序,采用相应的生物信息软件对核苷酸及氨基酸序列比对及基因亲缘关系进化特征分析.结果 2016年盐城地区麻疹病毒经基因型分型为H1a基因亚型和D8基因型.5株H1a代表株与江西代表株（KJ136545）聚集成簇形成独立的进化小分支,属H1a-1进化基因群分支;7株D8代表株与2009年美国代表株（JN635404）聚集成簇,属D8-3-2小分支基因群毒株.与疫苗株沪S191相比,盐城地区5株H1a基因亚型代表株240位氨基酸发生了S240 N的变异,丢失了238位N-连接的糖基化位点,7株D8基因型代表株未发生N-糖基化位点的变化.结论 2016年盐城地区麻疹病毒流行株主要为中国本土H1a优势基因亚型和D8输入基因型;除5株H1a基因亚型代表株丢失了238位N-连接的糖基化位点,盐城地区12株麻疹病毒HA基因大部分重要中和抗原位点未发生变异.

Objective To analyze the genotypes and the genetic evolution of the hemagglutinin genes of measles viruses in the city of Yancheng in 2016.Methods Using a set of primers and probes for screening positive for measles viruses,specimens of throat swab were detected using the method of real time RT-PCR.The sequences of the nucleoprotein and hemagglutinin genes of measles viruses were amplified through one step RT-PCR method and the PCR products were sequenced.The sequences of nucleotide and amino acid of the nucleoprotein and hemagglutinin genes of measles viruses were analyzed and the evolutional trees were generated using bioinformatics software.Results The genotypes of measles viruses in the Yancheng area in 2016 included subgenotype H1 a and genotype D8.Phylogenetic trees analysis showed that the five representative strains of subgenotype H1a in Yancheng area and Jiangxi representative strain （KJ136545） clustered into independent evolutionary branches,belonged to the clade of H1a-1 evolutionary genes.The seven representative strains of genotype D8 in Yancheng area were clustered with the American representative strain in 2009 （JN635404）,belonged to the D8-3-2 small clade genes.Compared with vaccine strain of Shanghai S191,the amino acid site in 240th of the five representative strains of subgenotype H1a in Yancheng area mutated from serine to asparagine,leading to a loss of the N-glycosylation site NLS238-240.The seven representative strains of genotype D8 in Yancheng area had no change in Nglycosylation.Conclusions In 2016,the prevalent strains of measles viruses in Yancheng area were mainly Chinese H1 a dominant subgenotype and D8 imported genotype.In addition to a loss of the N-glycosylation site NLS238-240 in 240th of the five representative strains of subgenotype H1 a,most of the major neutralizing antigen sites of hemagglutinin gene of measles viruses in Yancheng area did not mutate.The Chinese vaccine of Shanghai S191 can effectively prevent infection caused by subgenotype H1a and subgenotype D8 strains.