2株H9N2亚型AIV分离株的遗传演化及其对小鼠的致病性研究  

Phylogenetic analysis and pathogenicity of two H9N2 subtype avian influenza virus strains isolated from mice

作　　者：田苗 范梦璐 郑一青 平继辉[1] TIAN Miao;FAN Menglu;ZHENG Yiqing;PING Jihui(College of Veterinary Medicine,Nanjing Agricultural University,Nanjing 210095,China)

机构地区：[1]南京农业大学动物医学院,江苏南京210095

出　　处：《畜牧与兽医》2021年第6期90-98,共9页Animal Husbandry & Veterinary Medicine

基　　金：国家自然科学基金(31772775);国家重点研发计划(2016YFD0500206);兽医病原生物学国家重点实验室开放基金(SKLVEB2018KFKT006)。

摘　　要：为了解江苏地区H9N2亚型禽流感病毒(AIV)流行株的生物学特性,从江苏某养殖场分离到2株H9N2亚型AIV,A/chicken/Jiangsu/25/2019(CK/JS/25/19)和A/chicken/Jiangsu/43/2019(CK/JS/43/19),进行病毒纯化、全基因组测序、遗传进化分析,并研究其对小鼠的致病性。结果显示:2株分离株具有较高的同源性,与BJ/94、Y280、G1、F/98等代表性毒株同源性较低;HA、NA基因位于Y280分支,PB2、M基因位于G1分支,PB1、PA、NP、NS基因位于F/98分支,符合当前H9N2流行趋势;HA基因裂解位点的氨基酸组成为RSSR↓GLF,符合低致病性AIV特征;抗原性、受体结合特性、致病性等关键位点存在一定的变化,且HA、NA存在潜在糖基化位点的增加或缺失;小鼠试验表明,CK/JS/43/19对小鼠的致病性更强,且聚合酶活性更高。提示:近年来江苏地区H9N2亚型AIV发生了较大程度的进化,具有感染哺乳动物的潜在威胁,相关研究结果为监测和防控H9N2亚型AIV提供了理论参考。To investigate the biological characteristics of the H9 N2 subtype avian influenza virus(AIV)epidemic strains in Jiangsu Province,two H9 N2 subtype AIV isolates were obtained,namely A/chicken/Jiangsu/25/2019(CK/JS/25/19)and A/chicken/Jiangsu/43/2019(CK/JS/43/19).After virus purification,we performed whole genome sequencing,phylogenetic analysis,and pathogenicity in mice.The results showed that the two isolates were highly homologous,but they were of low homology with BJ/94,Y280,G1,F/98 and other H9 N2 representative strains.Phylogenetic analysis indicated that the HA and NA genes of the two isolates belonged to the Y280 branch,the PB2 and M genes were located in the G1 branch,and the PB1,PA,NP and NS genes were attached to the F/98 branch;all of which matched the current epidemic trend of H9 N2 viruses.Sequence analysis showed that the HA cleavage site of the two strains was RSSR↓GLF,which was consistent with the characteristics of the low pathogenic AIV.The key sites of antigenicity,receptor binding and pathogenicity were changed;meanwhile,the potential glycosylation sites in HA and NA were increased or deleted.The pathogenicity-in-mice data suggested that CK/JS/43/19 was more pathogenic and had higher polymerase activity than that of CK/JS/25/19.All these data indicated that the H9 N2 subtype AIV had wide variations and prompted potential threat to mammals.Therefore,this study provided a theoretical reference for monitoring,prevention and control of the H9 N2 subtype AIV.

关 键 词：H9N2 禽流感病毒 遗传进化 致病性 聚合酶活性 

分 类 号：S852.6[农业科学—基础兽医学]