一株H9N2亚型禽流感病毒抗原变异株产生原因的分析  

Analysis of the Antigen Variation of A H9N2 Avian Influenza Virus Strain

作　　者：乔淑媛 滕巧泱[2] 李雪松[2] 刘芹防[2] 张志飞 王思琪 李泽君[2] 杨健美[2] 王彩云[1] QIAO Shuyuan;TENG Qiaoyang;LI Xuesong;LIU Qinfang;ZHANG Zhifei;WANG Siqi;LI Zejun;YANG Jianmei;WANG Caiyun(College of Veterinary Medicine,Inner Mongolia Agricultural University,Hohhot 010018,China;Shanghai Veterinary Research Institute,CAAS,Shanghai 200241,China)

机构地区：[1]内蒙古农业大学兽医学院,呼和浩特010018 [2]中国农业科学院上海兽医研究所,上海200241

出　　处：《中国动物传染病学报》2024年第4期39-45,共7页Chinese Journal of Animal Infectious Diseases

基　　金：中国农业科学院创新工程基金(CAAS-ASTIP-SHVRI-2014-4);国家青年科学基金项目(31700136);上海市科技兴农项目(2021-02-08-00-12-F00746);中央级公益性科研院所基本科研业务费专项(JB03)。

摘　　要：目前,H9N2亚型禽流感病毒是我国最主要的低致病性禽流感病毒,造成禽养殖业的严重经济损失。H9N2禽流感病毒灭活疫苗是防控该疫病的最有效方式,然而,H9N2病毒在免疫压力下容易产生抗原变异,导致疫苗免疫失败,其机制尚不清楚。在前期研究中,我们通过模拟H9N2禽流感免疫压力筛选出携带HA_(D201N)单点突变的逃逸株,但HA_(D201N)如何导致H9N2病毒逃逸株出现的原因尚不明确。为此,本研究利用8质粒反向遗传技术方法拯救出1株A/Chicken/Shanghai/1/2006(H9N2)(简称SH1)及其免疫逃逸株rSH1-HA_(D201N)。为了鉴定HA_(D201N)是否通过影响H9N2禽流感病毒复制能力而导致病毒发生免疫逃逸,用0.001 MOI的病毒接种MDCK并测定其生长曲线,结果表明HA_(D201N)点突变可显著降低rSH1病毒的复制能力,且病毒复制能力的变化不是rSH1病毒发生逃逸的主要原因。为了研究HA_(D201N)是否通过影响H9N2病毒抗原变异而产生病毒逃逸株,将原毒株与突变毒株加入佐剂后免疫鸡以制备多克隆抗体血清,利用交叉HI试验,计算R值并分析抗原变异,结果表明rSH1与rSH1-HA_(D201N)的R值为2,说明HA_(D201N)会导致rSH1发生显著的抗原变异,从而使病毒在免疫压力下逃逸。本研究为探索H9N2禽流感病毒抗原变异规律及其疫苗研发奠定了基础。At present,the H9N2 subtype avian influenza virus is the most important low pathogenic variant in China,causing serious economic losses to the poultry industry.The inactivated H9N2 avian influenza virus vaccine is the most effective way to prevent and control the disease.However,the H9N2 virus is prone to antigenic variation under immune pressure,resulting in the failure of vaccine immunity.The mechanism is still unclear.In the previous study,we screened escape strains carrying a single point mutation of HA_(D201N)by simulating the immune stress of H9N2 avian influenza but the reason why HA_(D201N)led to the emergence of H9N2 virus escape strains was still unclear.In the present study,we rescued a strain of A/Chicken/Shanghai/1/2006(H9N2)(rSH1)and its immune escape strain rSH1-HA_(D201N)by using the 8-plasmid reverse genetic technology.In order to identify whether HA_(D201N)caused immune escape of the virus by affecting the replication ability of H9N2 avian influenza virus,MDCK cells were inoculated with the rSH1 virus at 0.001 MOI and its growth curve was measured.The results showed that the point mutation of HA_(D201N)significantly reduced the replication ability of rSH1 virus but the change of virus replication ability was not the main reason for the escape of rSH1 virus.In order to investigate whether HA_(D201N)produced virus escape strains by affecting the antigenic variation of H9N2 virus,the original virus and mutant virus were emulsified with adjuvant to immunize chickens for preparation of antiserum.Cross-HI test was used to calculate the R value and analyze the antigenic variation.The R value of rSH1-HA_(D201N)was 2,indicating that HA_(D201N)caused significant antigenic variation in rSH1,allowing the virus to escape immune stress.This study laid a foundation for further exploring the antigenic variation of H9N2 avian influenza virus and vaccine development.

关 键 词：H9N2亚型禽流感病毒 反向遗传技术 点突变 免疫逃逸 

分 类 号：S852.65[农业科学—基础兽医学]