一株野鸟源H1N1亚型禽流感病毒的遗传演化及其对小鼠的致病性分析  

Genetic evolution of a wild bird H1N1 subtype avian influenza virus and its pathogenicity in mice

作　　者：王冬雪 穆国冬[2] 侯玉杰[1] 李斌 邓国华[1] 崔鹏飞[1] 施建忠[1] 陈化兰[1] WANG Dong-xue;MU Guo-dong;HOU Yu-jie;LI Bin;DENG Guo-hua;CUI Peng-fei;SHI Jian-zhong;CHEN Hua-lan(State Key Laboratory of Veterinary Biotechnology,National Poultry Laboratory Animal Resource Center,Harbin Veterinary Research Institute,Chinese Academy of Agricultural Sciences,Harbin 150069,China;Jilin Province Center for Animal Disease Control and Prevention,Changchun 130000,China)

机构地区：[1]中国农业科学院哈尔滨兽医研究所兽医生物技术国家重点实验室/国家禽类实验动物资源库,黑龙江哈尔滨150069 [2]吉林省动物疫病预防控制中心,吉林长春130000

出　　处：《中国预防兽医学报》2022年第9期915-920,共6页Chinese Journal of Preventive Veterinary Medicine

基　　金：国家重点研发项目(2021YFD1800200、2021YFC2301700);国家自然基金重大项目(32192451)。

摘　　要：为了解野鸟源H1N1亚型禽流感病毒(AIV)的分子特征及其对哺乳动物小鼠模型的致病风险,本研究对2020年分离到的一株H1N1亚型AIV A/wildbird/Jilin/SM199/2020(H1N1)(简称WB/JL/SM199/2020)进行基因组序列及遗传演化分析,并评估了其对BALB/c小鼠的致病力。序列分析结果显示,分离株的8个基因节段分别与GISAID数据库中的野鸟源H1N1、H6N1、H11N9、H7N7、H1N2、H12N8和H3N8亚型AIV各基因节段的同源性较高,达98%以上,表明该病毒基因来源复杂,具有明显的遗传多样性。系统发育分析结果显示,该病毒的HA和NA基因均属于欧亚分支。各蛋白氨基酸序列分析结果显示,该病毒HA蛋白裂解位点基序为^(324)PSIQSR↓GLFG^(333),符合低致病性AIV(LPAIV)特征;其内部蛋白氨基酸序列存在多处对小鼠致病力增强的氨基酸突变,如PB1蛋白的D^(622)G、NS1蛋白的I^(106)M、C_(138)F和V^(149)A突变、M1蛋白的I^(43)M和T^(215)A突变。小鼠致病性试验结果显示,该病毒仅能在小鼠的鼻甲和肺脏中有效复制,病毒滴度均在3log_(10)EID_(50)/mL以上。而在小鼠的脑、脾脏和肾脏中均未检测到该病毒,且感染组与阴性对照组小鼠均无相应临床症状,体质量均无明显降低。以上结果表明该H1N1亚型AIV对小鼠呈低致病力。本研究为野鸟源H1N1亚型AI的防控提供了数据参考,并为其生物学特征的进一步研究奠定了基础。To investigate the molecular characteristics of the H1N1 subtype avian influenza virus(AIV)and its pathogenic risk to mammals,one virus,A/wild bird/Jilin/SM199/2020(H1N1)(WB/JL/SM199/2020),isolated from fecal samples collected in the wild bird habitants in 2020 in this study,it's genome sequence and genetic evolution were analyzed,and the pathogenicity was evaluated in BALB/c mice.Genetic analysis showed that the 8 gene segments of the isolated strain have high homology of more than 80%with the gene segments of wild bird H1N1,H6N1,H11N9,H7N7,H1N2,H12N8 and H3N8 subtypes AIV in Gisaid database,indicating that the virus has complex gene sources and distinct genetic diversity.Phylogenetic analysis showed that the HA and NA genes of the virus belonged to the Eurasian branch.The HA cleavage site of the H1N1 virus was^(324)PSIQSR↓GLFG^(333),which was consistent with the characteristic of lowly pathogenic avian influenza virus.Moreover,several amino acid changes related to increased replication and virulence in mammals were detected in the internal genes of the H1N1 isolate,such as D^(622)G in PB1,^(106)M,C^(138)F and V^(149)A in NS1,I^(43)M and T^(215)A in M1.The pathogenicity and virulence test of the H1N1 virus in mice showed that the virus replicated effectively in the nasal turbinate and lungs with viral titers all above 3log_(10)EID_(50)/mL,but the virus was not detected in the brain,spleen,and kidneys of the infected mice.In addition,the infectious mice had no corresponding clinical symptoms and no significant reduction in body weigh compared with the mice in the negative control group,and suggested that the H1N1 virus was low-pathogenic in mice.Our study provides data support for the prevention of H1N1 AI in wild birds and emphasizes the need for continuous surveillance of influenza in China.

关 键 词：H1N1亚型禽流感病毒 野鸟 遗传演化分析 致病性 

分 类 号：S852.65[农业科学—基础兽医学]