四株分离自同一猪场的H3N2亚型猪流感病毒的进化分析  

Phylogenetic Analysis of Four Strains of H3N2 Swine Influenza Virus Isolated from the Same Pig Farm

作　　者：余良政 丁仰保 何剑桥 刘林林 崔柏杨 韦祖樟[1] 欧阳康[1] 黄伟坚[1] 陈樱[1] YU Liangzheng;DING Yangbao;HE Jianqiao;LIU Linlin;CUI Baiyang;WEI Zuzhang;OUYANG Kang;HUANG Weijian;CHEN Ying(Laboratory of Animal Infectious Disease and Immunology,College of Animal Science and Technology,Guangxi University,Nanning 530004,China)

机构地区：[1]广西大学动物科学技术学院家畜传染病与分子免疫学实验室,南宁530004

出　　处：《畜牧兽医学报》2020年第4期801-809,共9页ACTA VETERINARIA ET ZOOTECHNICA SINICA

基　　金：广西自然科学基金青年基金项目(2016GXNSFBA380219);广西自然科学基金联合资助培育项目(2018GXNSFAA294048);广西创新驱动发展专项资金项目(桂科AA17204057-1)。

摘　　要：猪作为流感病毒异源毒株间发生基因重组的“混合容器”,其呼吸道上皮细胞上同时存在着能够感染人(SAα-2,6-Gal)和禽(SAα-2,3-Gal)两种流感病毒的受体,具备产生新型流感病毒的潜力。在我们的前期研究中,连续两年(2013年和2014年)从南宁地区某个规模化养猪场当中分离获得了2株新型甲型流感病毒重配的H3N2亚型猪流感病毒(swine influenza viruses,SIVs)。为了解SIVs在同一地方的遗传进化规律,我们在2018年至2019年间对该猪场进行了持续的监测,并于2019年再次成功分离获得了2株H3N2亚型的三源重组毒株,命名为A/swine/Guangxi/JG13/2019(简称JG13/2019)和A/swine/Guangxi/JG20/2019(简称JG20/2019)。遗传进化分析表明其基因重配形式与2013年分离株A/swine/Guangxi/JGB4/2013(简称JGB4/2013)和2014年分离株A/swine/Guangxi/JG1/2014(简称JG1/2014)相同,表面基因HA和NA来源于类人H3N2谱系,内部基因NP、M、PA、PB 1和PB 2来源于2009年甲型H1N1大流感谱系(pdm/09H1N1),NS基因来源于古典型H1N1谱系。此外,新分离株JG13/2019和JG20/2019同早期分离株JGB4/2013和JG1/2014 HA和NA基因的核苷酸相似性分别为95.3%~97.4%和93.9%~97.0%,内部基因(NP、M、PA、PB 1和PB 2)的核苷酸相似性为96.2%~98.1%,NS基因的核苷酸相似性为97.1%~97.6%。通过分析比较这些年代不同毒株之间的关键氨基酸位点差异,结果发现JG20/2019和JG13/2019的HA蛋白仍旧保持了与人型受体结合的分子特征(190D、226I和228S),却也出现了V223I或P227S的新变化,JG13/2019的PA蛋白(R356K)和PB2蛋白(I588T)也与之前的毒株有所不同。这些位点上的氨基酸改变是否影响到病毒的致病能力、复制能力以及跨种间传播能力,有待今后进一步研究。历经6年,携带有pdm/09 H1N1多种内部基因片段(PB 2、PB 1、PA、M、NP)和类人表面基因(HA和NA)的H3N2亚型SIVs依旧在同一个猪场的猪群中流行,虽然其关键的功能区域出现了基因突变,但是Pigs are regarded as a“mixing vessel”of influenza viruses,who could reassort with heterologous strains.They pose a potential threat to human health,due to the existence of the human-type(SAα-2,6-Gal)and the avian-type(SAα-2,3-Gal)receptors on the respiratory epithelial cells.Our previous study showed that two novel reassortants H3N2 swine influenza viruses(SIVs)with 2009 pandemic H1N1 internal genes were isolated in 2013 and 2014 from a large-scale pig farm of Nanning.To understand the genetic evolution of SIVs in the same pig farm,the consecutive surveillance was performed from 2018 to 2019.Two triple-reassortant H3N2 SIVs named as A/swine/Guangxi/JG13/2019(JG13/2019)and A/swine/Guangxi/JG20/2019(JG20/2019)were isolated once more in the pig farm mentioned above in 2019.The analysis of phylogenetic tree demonstrated that their reassortant form were similar to previous strains,A/swine/Guangxi/JGB4/2013(JGB4/2013)and A/swine/Guangxi/JG1/2014(JG1/2014),containing the surface genes HA and NA derived from the human-like H3N2 lineage,the internal genes NP,M,PA,PB 1 and PB 2 derived from the pdm09/H1N1 lineage and the NS gene derived from the classical swine H1N1 lineage.Besides,the homologies of HA and NA genes between the new isolates and previous isolates were 95.3%-97.4%and 93.9%-97.0%,respectively at the nucleotide level.The internal genes(NP,M,PA,PB 1 and PB 2)were 96.2%-98.1%,NS genes were 97.1%-97.6%.It was found that the protein HA still remained 190D,226I and 228S which bind to human receptor.However,there were still two mutations at the position 223(V→I)and 227(P→S).Furthermore,there were two sites different from previous strains on PA protein and PB2 protein,which were R→K at the position 356 and I→T at the position 588.Whether these changes could affect the pathogenicity,replication and the ability of cross-species transmission needs to be further studied in future.After six years,H3N2 SIVs carrying internal gene fragments(PB 2,PB 1,PA,M and NP)of pdm/09 H1N1 and human-like surface genes(HA an

关 键 词：H3N2亚型 猪流感病毒 进化分析 分子特征 

分 类 号：S852.659.5[农业科学—基础兽医学]