铜川市2013-2015年A型流感病毒HA基因特性研究

Characteristics of HA gene of influenza A virus in Tongchuan City,2013-2015

目的应用生物信息学数据库和工具,了解2013-2014年铜川市A型H1N1和2013-2015年A型H3N2流感病毒血凝素(HA)基因特性及其抗原变异情况。方法收集铜川市哨点医院流感样病例标本,采用MDCK细胞分离流感病毒。用RT-PCR对部分A型H1N1、H3N2流感病毒进行HA基因序列扩增和纯化,序列测定,并用MEGA软件构建种系发生树分析。结果 2013-2015年铜川市流感核酸检测标本共2 333份,流感阳性476份,阳性率20.40%。4株A型H1N1亚型流感病毒与WHO推荐A/California/07/2009(H1N1)疫苗株氨基酸序列比对,共发生11次氨基酸突变,其中3个氨基酸位点突变发生在抗原决定簇。3株A型H3N2亚型与WHO推荐的北半球2013-2014年A/Victoria/361/2011(H3N2)疫苗株比对共有9个氨基酸位点发生了突变,其中3个氨基酸位点发生在抗原决定簇;与WHO推荐的北半球2014-2015年A/Texas/50/2012(H3N2)疫苗株比对共有10个氨基酸位点发生了突变,有5个氨基酸位点发生在抗原决定簇。结论 2013-2015年铜川市流行的A型H1N1、H3N2亚型流感病毒氨基酸发生突变导致抗原漂移。

Objective To define the genetic characteristics of hemagglutinin of influenza A （H1N1） virus from 2013 to 2014 and of influenza A （H3N2） virus from 2013 to 2015 as well as their antigen mutations in Tongchuan City by bioinformatics data-base and tools. Methods Nasopharyngeal swab specimens were collected from patients with influenza-like illness in sentinel hospitals in Tongchuan City. Influenza viruses were isolated with MDCK cells. Hemagglutinin genomic sequences of parts of type A H1N1 and H3N2 influenza viruses were amplified and purified by RT-PCR, and then sequenced and analyzed with phylogenetic tree using MEGA software. Results A total of 2,333 suspected influenza specimens were detected for nucleic acid in Tongchuan City from 2013 to 2015, and 476 were positive for influenza viruses, with the positive rate of 20.40%. Comparison of amino acid sequences of four strains of H1N1 virus with A/California/07/2009 （H1N1） vaccine strain recommended by WHO showed that there were a total of 11 amino acid mutations, with 3 mutations occurring in the antigenic determinant. As for the amino acid sequences of three strains of type A H3N2 influenza viruses, when they were compared with A/Victoria/361/2011（H3N2） vaccine strains for the northern hemisphere in 2014-2015 recommended by WHO, 9 amino acid mutations were found, with 3 mutations in the antigenic determinant. When they were compared with A/Texas/50/2012 （H3N2） vaccine strains for the northern hemisphere in 2014-2015 recommended by WHO, 10 amino acid mutations were found, with 5 mutations in the antigenic determinant. Conclusions Amino acid mutations occur in the hemagglutinin antigenic sites in type A H1N1 and H3N2 influenza viruses prevalent in Tongchuan City in 2013-2015, which results in antigenic drift.