2019-2020年山东省A(H1N1)pdm09亚型流感病毒抗原性及血凝素基因特征分析

Analysis of the genetic characteristics of hemagglutinin and the antigenicity of influenza A(H1N1) pdm09 virus strains isolated in Shandong from 2019-2020

目的了解山东省2019-2020年分离株A(H1N1)pdm09亚型流感病毒的抗原性及血凝素(hemagglutinin, HA)基因变异情况。方法采用单向红细胞凝集抑制试验对2019-2020监测年分离的15株A(H1N1)pdm09亚型流感病毒进行抗原性分析;PCR扩增病毒的HA基因并测序,进行进化分析,以及糖基化位点、抗原变异位点、受体结合位点的变异分析。结果 2019-2020年流行株A(H1N1)pdm09亚型流感病毒均为疫苗株A/Brisbane/02/2018的类似株。HA基因均属于6B.1分支,毒株HA基因核苷酸序列与当季疫苗株A/Brisbane/02/2018的同源性为98.5%~99.0%,与最新疫苗株A/Guangdong-Maonan/SWL1536/2019的核苷酸同源性为99.3%~99.8%。所有毒株与当季疫苗株相比均出现了T185I位点变异。结论 2019-2020监测年度山东省流行的A(H1N1)pdm09亚型流感病毒与WHO推荐的疫苗组分匹配性良好,疫苗株推荐存在滞后性。HA基因与其编码的氨基酸持续变异,因此应加强对病毒变异的监测,为疫苗筛选及流感防控措施的制定提供参考。

Objective To analyze the antigenicity, genetic characteristics, and variation of the hemagglutinin(HA) protein of the influenza A(H1 N1)pdm09 virus circulating in Shandong from 2019-2020. Methods Fifteen strains of influenza virus subtype A(H1 N1)pdm09 that were isolated from 2019-2020 were analyzed via a hemagglutination inhibition test. The HA gene of these strains was sequenced and their genetic characteristics were analyzed, including evolutionary analysis and analysis of glycosylation sites, sites of antigenic variation, and variations in receptor binding sites. Results Antigenicity analysis indicated that all of the monitored strains were similar to vaccine strain A/Brisbane/02/2018. Sequencing indicated that the HA gene of the influenza A(H1 N1) pdm09 subtype that was prevalent from 2019 to 2020 all belonged to the 6 B.1 clade. The nucleotide sequence of the HA gene of the monitored strain was 98.5-99.0% similar to the current seasonal influenza vaccine strain A/Brisbane/02/2018 and 99.3-99.8% similar to the latest vaccine strain A/Guangdong Maonan/SWL1536/2019. All strains exhibited the T185 I mutation. Conclusion Strains of the influenza virus subtype A(H1 N1)pdm09 circulating in Shandong closely matched the vaccine strain A/Brisbane/02/2018 as recommended by the WHO, but there is a lag in the recommendation of influenza virus vaccine strains. The HA gene and the amino acids it encodes continue to mutate, so surveillance of influenza virus variation needs to be monitored in order to provide effective data for vaccine screening and influenza prevention and control.