H3N2犬流感病毒PB2 D701N位点突变对小鼠致病性的影响

Effects of PB2 D701N mutation on the pathogenicity of H3N2 canine influenza virus in mice

为探究PB2基因D701N突变对犬流感病毒(canine influenza virus,CIV)H3N2的致病性影响,利用本实验室构建的CIV H3N2(A/canine/Guangdong/02/2011,C/GD/02)反向遗传系统和定点突变技术,获得了2株拯救病毒(原毒株:r C/GD/02,突变株:r C/GD/02-701N)。聚合酶活性试验结果显示,突变株的聚合酶活性显著强于原毒株(P<0.05),说明PB2 D701N的突变能显著增强CIV H3N2聚合酶活性;病毒生长曲线显示,突变株比原毒株在MDCK细胞中的生长复制能力有所下降;小鼠致病性试验显示,两毒株均导致了小鼠的体重增长速率轻微下降,但毒株间无显著差异,且均未导致小鼠死亡。结果表明,PB2基因D701N的突变不会显著影响CIV H3N2对小鼠的致病性。

In order to explore the effect of PB2 D701N mutation on the pathogenicity of H3N2 canine influenza virus（CIV）,we rescued two viruses（wild-type virus：rC/GD/02,mutation virus：rC/GD/02-701N） by reverse genetic system and site-directed mutagenesis technology. The polymerase activity assay showed that the polymerase activity of the mutant virus was significantly stronger than that of the wild-type virus（P〈0.05）,indicating PB2 D701N mutation could significantly enhance the polymerase activity of HZN2 CIV.The virus growth curve showed that,comparing wild-type virus,the virus replication ability of mutation virus was decreased slightly in MDCK cells. The mice experiment showed that the two strains resulted in a slight decrease in the weight gain rate in mice,hut there was no significant difference between two groups and did not cause the mice to die,indicating that PB2 D701N mutation has no significant effects on the pathogenicity of CIV H3N2 in mice.