The present paper aims to compare the hemagglutinin (HA ) gene of a seasonal influenza A (H1N1) virus isolated in 2011 with the gene from reported seasonal influenza A (H1N1 ) viruses . The HA fragment and full-genome of A/Shanghai /1167/2011 (H1N1) were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR ). Molecular biology software was used to analyze the sequences and draw the phylogenetic tree. The anti-virus antibody level in healthy people was detected by hemagglutination inhibition test. The results showed that the HA gene of A/Shanghai/ll67/2011 (H1N1) was similar to the HA genes from previous reported seasonal influenza A (H1N1) viruses, with homology of 99.2% to the 2008-2009 seasonal influenza A(H1N1) vaccine strain A/Brisbane/59/2007 (H1N1), and 72.4% to the A/ California/07/2009 vaccine strain respectively. The HA cleavage site was PSIQSR ↓ GLF, and highly pathogenic molecular characteristics had not appeared yet . HA fragment, encoding 557 amino acids , has nine potential glycosylation sites . Its amino acid sequence was compared with the World Health Organization (WHO) vaccine strains of influenza A/NewCaledonia/20/l999(HlNl) , A/SolomonIslands/3/2006(HlNl) , and A/Brisbane/59/2007 (H1N1 ) respectively. The identified amino acid differences were 15, 12 and 4 respectively, and part of these differences (5 A 5, 5/12 and 2/5) were located inside the critical epitope clusters (Sa, Sb, Cal, Ca2 and Cb) . Our results indicated that in 2011, 34 .33% of healthy people carried antibodies against the isolated strain in their sera , and the geometric mean titer (GMT) was 10.38. A/ Shanghai/1167/2011 (H1N1) is a seasonal influenza A(H1N1) strain isolated in Shanghai in 2011 . Although no significant differences were identified when comparing it to seasonal influenza A (H1N1 ) viruses , its detection after A(HlNl)pdm09 was identified as the predominant strain should arouse people 's attention . Its antibody level in population is low , and can easily cause a pandemic . The monitoring of such strains in influenza-like population should be improved .%本文通过比较2011年分离培养的1株季节性甲型H1N1流行性感冒(简称流感)病毒(A/Shanghai/1167/2011(H1N1))与历年季节性甲型H1N1流感病毒的血凝素(HA)基因,追溯该病毒的基因变异与来源,探讨该毒株的出现对流感防控工作的意义.采用反转录-聚合酶链反应(RT-PCR)方法扩增病毒的HA和神经氨酸酶(NA)片段,并进行测序;应用分子生物学软件对获得的序列进行分析,绘制基因进化树;同时,通过血凝抑制试验检测2011年下半年健康人群中该流感病毒的抗体水平.结果显示,A/Shanghai/1167/2011(H1N1)的HA基因序列与世界卫生组织(WHO)2007～2008年季节性甲型H1N1流感病毒疫苗株A/Brisbane/59/2007(H1N1)最接近,同源性达99.2%,与新型甲型H1N1流感病毒A/California/07/2009疫苗株同源性仅为72.4%.其HA基因裂解位点为PSIQSR↓GLF,尚未出现高致病性的分子特征.HA片段共编码557个氨基酸,有9个潜在的糖基化位点,序列与2009年前WHO疫苗株A/NewCaledonia/20/1999(H1N1)、A/SolomonIslands/3/2006(H1N1)和/Brisbane/59/2007(H1N1)相比,分别有15、12和4处不同,这些差异分布在Sa、Sb、Ca1、Ca2、Cb 5个抗原决定簇的氨基酸差异分别有5、5和2处.该毒株在健康人群血清的抗体阳性率为34.33%,几何平均效价(GMT)为10.38.A/Shanghai/1167/2011(H1N1)是2011年出现在上海地区的一个季节性甲型H1N1流感病毒毒株,其抗原变异与既往季节性甲型H1N1流感病毒相比不大,但在以A(H1N1)pdm09为主要流行株的年份检测到散在发生的既往季节性甲型H1N1流感病毒毒株应当引起重视,其在人群中的抗体水平较低,易引起流行,需要提高对类流感人群中此种毒株的持续监测.
展开▼
