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目的了解北京市房山区2014—2015年H3N2亚型流感病毒HA1基因变异情况。方法随机分别选择2014—2015年流感病原学监测中分离到的H3N2型毒株共26株,采用RT-PCR法扩增病毒目的基因片段后进行序列测定,与WHO推荐的北半球疫苗株及常见H3N2毒株进行比对并构建进化树。采用MEGA6软件对测序结果进行分析,同源性计算使用BLAST网站,利用NetNGlyc 1.0软件进行糖基化位点预测。结果 2014—2015年房山区H3N2亚型流感病毒HA1目的基因片段序列测定拼接后最长核苷酸片段为703 bp最短核苷酸片段为696 bp,没有核苷酸的丢失,编码氨基酸为232-234个;抗原表位A抗原表位和D抗原表位有变异;受体结合位点第228位由丙氨酸变为丝氨酸,第130位由丝氨酸变为苏氨酸;做进化树分析,发现该分析中的H3N2亚型流感病毒位于2个分支上,分别为A/Switzerland/9 715 293/2013和A/HongKong/5 738/2014,大部分与前者在一个分支。结论北京市房山区2014—2015年H3N2流感病毒的血凝素重链区HA1基因特性有部分变化,抗原表位A抗原表位和D抗原表位有变异,且在基因进化上与当年的疫苗株分属不同分支,具有一定的进化距离,相似度较低,可能导致H3N2流行。
Objective To investigate the variation of HA1 gene of H3N2 subtype influenza virus in Fangshan District of Beijing from 2014 to 2015. Methods A total of 26 strains of H3N2 were randomly selected from influenza aetiology surveillance in 2014-2015. The amplified products of the target gene were sequenced by RT-PCR and compared with the WHO-recommended northern vaccine strains and common H3N2 Strains were aligned and the phylogenetic tree constructed. Sequencing results were analyzed using the MEGA6 software, homology calculations using the BLAST website and NetNGlyc 1.0 software for glycosylation site prediction. Results The sequence of HA1 gene fragment in Fangshan H3N2 subtype influenza virus from 2014 to 2015 was determined to be 696 bp with the longest nucleotide fragment of 703 bp after splicing. There was no nucleotide loss and the amino acid sequence of 232- 234; the antigenic epitope A antigen epitope and the D antigenic epitopes have variation; the binding site of the 228th from alanine to serine, 130th from serine to threonine; do phylogenetic tree analysis, The H3N2 subtype influenza virus in this assay was found to be located on two branches, A / Switzerland / 9 715 293/2013 and A / HongKong / 5 738/2014, respectively, most of which were in a branch with the former. Conclusion The characteristics of HA1 gene in hemagglutinin heavy chain region of H3N2 influenza virus in Fangshan District of Beijing from 2014 to 2015 are partially changed. The epitopes of antigenic epitopes A and D are mutated. Strains belonging to different branches, with a certain degree of evolutionary distance, low similarity, may lead to H3N2 epidemic.