1998-2009年浙江省H3N2亚型流行性感冒病毒全序列变异的研究

目的 比较1998-2009年浙江省H3N2亚型流行性感冒(简称流感)流行株HA基因进化与全基因进化状况的一致性,并探讨全基因组序列上可能存在的潜在抗原区域.方法 选择浙江省CDC流感实验室于1998-2009年流感疫情中分离保存的H3N2亚型流感流行代表株19株,采用RT-PCR法进行全基因组序列扩增,并将这些毒株与10株同期H3N2亚型流感疫苗株进行全序列及HA1基因的系统进化比较;通过氨基酸替换比较、熵值计算及正向选择位点的筛选,确定各基因上的氨基酸易变位点.结果 H3N2亚型流感病毒的全序列长度为4466个氨基酸,其中有137个氨基酸位点发生稳定变异.在HA基因上第144和158位氨基酸分别经历了4次和3次替换,NA基因的第93、143、307、370、372位氨基酸和NP基因的第450位氨基酸经历了2次替换,且HA基因和NA基因上分别有29%(12/41)和77%(24/31)的变异位点位于已知抗原决定簇之外的区域.氨基酸位点熵值分析显示,HA基因非抗原决定簇的3、225、361位,NA基因非抗原决定簇的93、143、147、150、372位,PB1基因的113、576、586位,PA基因的101、256、382、421、437位,NP基因的377、450位,M1基因的218位及M2基因的31位氨基酸均为易变位点.结论 浙江省1998-2009年H3N2亚型流感病毒在HA和NA已知抗原决定簇之外的区域与部分内部基因上,可能存在着一些尚未被发现或者新形成的抗原位点.与HA基因的系统进化比较,全序列能更为全面地反映出流感流行株之间的亲缘关系与进化规律.

Abstract：

Objective To analyze the consistency of evolution condition between HA gene and the whole genome of influenza virus subtype A/H3N2 strains isolated in Zhejiang province from 1998 to 2009,and to study the potential antigenic region on the whole genome.Methods The sequences of whole genome of 19 Zhejiang influenza virus isolates circulated from 1998 to 2009,which conserved by influenza laboratory of Zhejiang Provincial Centre for Disease Prevention and Control,were amplified using RT-PCR assays.The obtained sequences were used to conduct phylogenetic analysis with 10 contemporaneous vaccine strains.Three methods,including comparison of the amino acid substitutions,calculation of the entropy value and the filtering of positive selection sites,were used to confirm the mutable sites on each gene.Results The whole genome of influenza virus subtype A/H3N2 was 4466 amino acids in length,with 137 stable mutations.The 144,158 aa of HA gene mutate four and three times respectively; 93,143,307,370,372 aa of NA gene and 450 aa of NP gene mutate twice,and there were 29%(12/41) and 77%(24/31) mutations of HA and NA genes occurred on the non-epitope regions respectively.Analysis of the entropy value suggest that many amino acid sites on the non-epitope regions were prone to mutation,including 3,225,361 aa of HA gene; 93,143,147,150,372 aa of NA gene; 113,576,586 aa of PB1 gene; 101,256,382,421,437 aa of PA; 377,450 aa of NP gene; 218 aa of M1 gene and 31 aa of M2 gene.Conclusion Based on the whole genome of influenza virus subtype A/H3N2 strains isolated in Zhejiang province in 1998 to 2009,there may be several unknown or new antigen sites existing on the non-epitope regions of HA and NA genes and parts of internal genes.The phylogenetic tree constructed based on the complete sequence was more comprehensive than on the HA gene to reflect the genetic relationship and law of evolution among the influenza virus strains.

Study on the mutations within the whole genome of influenza virus subtype A/H3N2 strains circulated in Zhejiang province from 1998 to 2009

Objective To analyze the consistency of evolution condition between HA gene and the whole genome of influenza virus subtype A/H3N2 strains isolated in Zhejiang province from 1998 to 2009,and to study the potential antigenic region on the whole genome.Methods The sequences of whole genome of 19 Zhejiang influenza virus isolates circulated from 1998 to 2009,which conserved by influenza laboratory of Zhejiang Provincial Centre for Disease Prevention and Control,were amplified using RT-PCR assays.The obtained sequences were used to conduct phylogenetic analysis with 10 contemporaneous vaccine strains.Three methods,including comparison of the amino acid substitutions,calculation of the entropy value and the filtering of positive selection sites,were used to confirm the mutable sites on each gene.Results The whole genome of influenza virus subtype A/H3N2 was 4466 amino acids in length,with 137 stable mutations.The 144,158 aa of HA gene mutate four and three times respectively; 93,143,307,370,372 aa of NA gene and 450 aa of NP gene mutate twice,and there were 29%(12/41) and 77%(24/31) mutations of HA and NA genes occurred on the non-epitope regions respectively.Analysis of the entropy value suggest that many amino acid sites on the non-epitope regions were prone to mutation,including 3,225,361 aa of HA gene; 93,143,147,150,372 aa of NA gene; 113,576,586 aa of PB1 gene; 101,256,382,421,437 aa of PA; 377,450 aa of NP gene; 218 aa of M1 gene and 31 aa of M2 gene.Conclusion Based on the whole genome of influenza virus subtype A/H3N2 strains isolated in Zhejiang province in 1998 to 2009,there may be several unknown or new antigen sites existing on the non-epitope regions of HA and NA genes and parts of internal genes.The phylogenetic tree constructed based on the complete sequence was more comprehensive than on the HA gene to reflect the genetic relationship and law of evolution among the influenza virus strains.