天津市2018-2020年人轮状病毒株VP7、VP4和NSP4基因特征  

Gene characterization of human rotavirus strains VP7,VP4 and NSP4 in Tianjin,2018-2020

作　　者：雷玥[1] 庄志超 田宏[1] 李晓燕[1] LEI Yue;ZHUANG Zhi-chao;TIAN Hong;LI Xiao-yan(Department of Pathogen Detection,Tianjin Center for Disease Control and Prevention,Tianjin 300011)

机构地区：[1]天津市疾病预防控制中心病原生物检测室,天津300011

出　　处：《中国热带医学》2021年第7期639-647,共9页China Tropical Medicine

基　　金：国家科技重大专项传染病监测技术平台项目(No.2017ZX10103007-002);天津市科技局重点项目(No.20JCZDJC00130);天津市卫生健康委面上项目(No.MS20014)。

摘　　要：目的对天津流行的人A组轮状病毒VP7、VP4和NSP4基因进行分型和序列特征分析。方法收集2018—2020年天津市急性腹泻A组轮状病毒(Rotavirus group A,RVA)阳性病例的粪便标本,提取核酸,进行RT-PCR扩增VP7、VP4和NSP4基因片段全长并进行测序和进化树分析。结果本次研究所有RVA均属于G9P[8]基因型,进化树分析其VP7和VP4基因分别属于G9-VI和P[8]-3亚型。分析NSP4基因片段发现19株为E1型,12株为E2型。TJ株VP7、VP4、NSP4与疫苗株和参考株比对发现在关键位点有氨基酸替代现象。31个TJ-VP7氨基酸序列与Rotavac G9和Rotasiil G9 VP7相比,各有4个和3个替换位点。31例天津株VP8*核苷酸序列与Rotarix P[8]-1和RotaTeq相比,各有6个和3个氨基酸差异。天津株VP5*核苷酸与两种疫苗相比,仅在RotaTeq的5-1区I388L这一处发现氨基酸位点变异情况,其余11个氨基酸位点高度保守;而与Rotarix5-1到5-5区氨基酸序列完全一致。TJ E1株与疫苗株的NSP4序列相比在ASI和ASII区分别有2和3个氨基酸位点发生变异;TJ E2株与疫苗株的NSP4序列相比在ASI-ASIV分别有3、8、2和5个氨基酸位点发生替换。2018—2020年在天津地区检测到19株G9P[8]-E1型RVA,12株G9P[8]-E2型RVA,这是首次在天津发现G9P[8]-E2重组基因型。结论与同基因型疫苗株和参考株相比,位于TJ株VP7、VP4和NSP4抗原位点的改变对于疫苗保护效力的影响还需进一步研究。需要对轮状病毒分子变异和重组现象进行持续监测,不只是单一监测G/P分型情况,要考虑多基因片段共同分析和全基因组测序,以便及时追踪和掌握轮状病毒的重组和变异情况。Objectives To identify VP7,VP4 and NSP4 genotypes and analyze their sequence characterization of group A rotavirus(RVA)strains prevalent in Tianjin.Methods acute diarrhea in Tianjin during 2018-2020 were collected and viral RNA were extracted.VP7,VP4 and NSP4 gene fragments were amplified by RT-PCR and PCR products were sequenced to analysis phylogenetic tree.ResultsThe genotyping results showed that all RVA prevalent in Tianjing(TJ)strains in this study were G9 P[8].Phylogenetic analysis confirmed that VP7 and VP4 belonged to lineages G9-VI and P[8]-3.Phylogenetic analysis of NSP4 confirmed that 19 RVAs belonged to E1 and 12 RVAs belonged to E2.Comparison with vaccine strains and international epidemic strains showed VP7,VP4 and NSP4 genes of TJ strains had amino acid substitution at key sites.Thirty-one TJ-VP7 amino acid sequences were found with 4 and 3 substitution sites each compared to Rotavac G9 and Rotasiil G9.Six and three amino acid differences were found for thirty-one TJ-VP8*nucleotide sequences each compared with Rotarix P[8]-1 and RotaTeq.Compared with the two vaccines,only one amino acid site variation of TJ-VP5*was found in I388 L of 5-1 region of RotaTeq,and the other 11 amino acid sites were highly conserved,while the amino acid sequence of the Rotarix 5-1 to 5-5 region is identical.Compared with the vaccine strain,TJ-E1 strain had 2 and 3 amino acid mutations in ASI and ASII regions,respectively;TJ E2 strain had 3,8,2,and 5 amino acid substitutions in ASI-ASIV,respectively,compared to the NSP4 sequence of the vaccine strain.19 G9 P[8]-E1 and12 G9 P[8]-E2 were detected in Tianjin from 2018 to 2020,which is the first time a G9 P[8]-E2 reassortant(IGR)strains was found in Tianjin.ConclutionCompared to the same genotypic vaccines strains and epidemic strains,the effect of amino acids variations located in VP7,VP4 and NSP4 epitope regions of TJ strains on the protective efficacy of the vaccine needs to be further investigated.Continued monitoring of rotavirus molecular mutation and recombination phe

关 键 词：轮状病毒 基因型 重组 系统进化分析 

分 类 号：R512.5[医药卫生—内科学]