2019—2020年9株H9N2亚型禽流感病毒抗原性分析及候选疫苗株筛选  

The antigenicity of 9 strains of H9N2 subtype avian influenza virus in 2019-2020 and screening of candidate vaccine strain

作　　者：蒋文明[1,2] 张琳 彭程 刘朔[1,2] 尹馨 李金平[1,2] 侯广宇 刘华雷 JIANG Wenming;ZHANG Lin;PENG Cheng;LIU Shuo;YIN Xin;LI Jinping;HOU Guangyu;LIU Hualei(China Animal Health and Epidemiology Center,Qingdao 266032,China;Key Laboratory of Animal Biosafety Risk Prevention and Control(South),Qingdao 266032,China;Ulanqab Vocational College,Ulanqab 012000,China)

机构地区：[1]中国动物卫生与流行病学中心,山东青岛266032 [2]农业农村部动物生物安全风险预警及防控重点实验室(南方),山东青岛266032 [3]乌兰察布职业学院,内蒙古乌兰察布012000

出　　处：《畜牧与兽医》2023年第11期72-78,共7页Animal Husbandry & Veterinary Medicine

基　　金：山东省重点研发计划资助项目(2022CXGC010606)。

摘　　要：为了解近年来H9N2亚型禽流感病毒的分子特征和抗原变异情况,本研究对选自2019—2020年的9株H9N2亚型禽流感病毒的血凝素(HA)基因序列进行分析,进一步利用交叉血凝抑制试验和中和试验对抗原性进行分析,并以此筛选出候选疫苗株,开展免疫原性和攻毒保护试验研究。9株病毒HA基因核苷酸同源性为91.2%~98.9%,表明这些毒株之间HA基因分化明显。9株病毒HA蛋白裂解位点序列均为RSSR,符合低致病性禽流感病毒分子特征。所有9株病毒HA均含有7个潜在的糖基化位点。9株病毒HA关键受体结合位点的234位氨基酸由谷氨酰胺变为亮氨酸,提示这些毒株具有结合α2,6-Sialidase受体的能力。交叉血凝抑制试验显示各毒株之间出现最大64倍的抗原性差异,交叉中和试验显示各毒株之间出现最大1024倍的抗原性差异。根据中和试验结果,利用AntigenMap制作抗原图谱,可以看出9株病毒可以分为2个主要抗原群。筛选的Y2432毒株制备灭活疫苗免疫鸡群后21 d,针对同源毒株平均血凝抑制(HI)抗体效价达到13.6 log_2,使用同源毒株和异源毒株进行攻毒,保护率均为100%。Y2432免疫SPF鸡,14 d即可产生高水平抗体,最高可达到14.4 log_2,且抗体可维持140 d以上。筛选的候选疫苗株免疫原性和免疫保护效果较好,为预防H9N2亚型禽流感的流行提供了重要技术储备。To identify the molecular characteristics and antigen variation of H9N2 subtype avian influenza virus(AIV)in recent years,the HA gene sequences of the 9 strains of H9N2 subtype AIVs isolated in 2019-2020 were analyzed in this study.The antigenicity was further analyzed by cross-hemagglutination inhibition test and neutralization test,and a candidate vaccine strain was then screened out.Subsequent⁃ly,the immunogenicity and challenge protection tests were carried out.The results showed that the nucleotide homology of the HA gene of the 9 strains was 91.2%to 98.9%,indicating that the differentiation of the HA genes was obvious among these strains.The cleavage site se⁃quence of the HA protein of the 9 strains was RSSR,which was consistent with the molecular characteristics of low pathogenic AIV.All the 9 stains contained 7 potential glycosylation sites in the HA protein.The mutation of the amino acid site 234 changed from glutamine to leucine in the HA key receptor binding site,suggesting that these strains had the ability to bind theα2,6-Sialidase receptor.The cross-hemaggluti⁃nation inhibition(HI)test showed up to 64 times the antigenicity difference between the different strains,and the cross-neutralization test showed up to 1024 times the antigenicity difference between the different strains.According to the results of the neutralization test,the anti⁃genic map was made by the AntigenMap,which indicated that the nine virus strains could be divided into two main antigen groups.21 days after the chickens were vaccinated with the Y2432 inactivated vaccine,the average HI titer against the homologous strain reached 13.6 log2.The homologous and heterologous strains were used for challenge,and the protection efficiency was 100%.By immunizing SPF chickens with Y2432,a high level of antibody,up to 14.4 log2,were produced 14 days later,and the antibody could maintained for more than 140 days.The screened candidate vaccine presented high immunogenicity and immune protection efficiency,providing an important technic

关 键 词：禽流感 H9N2 抗原性 疫苗 

分 类 号：S852[农业科学—基础兽医学]