为了防控猪场塞内卡谷病毒(SVV)和圆环病毒2型(PCV2)的混合感染,本试验建立了一种猪SVV、PCV2嵌合病毒样颗粒疫苗的制备方法并进行抗体检测.试验将猪SVV P1基因部分VP3序列替换为PCV2ORF2基因C端部分多肽序列,利用杆状病毒表达系统获得表达猪SVV、PCV2嵌合重组蛋白的重组杆状病毒,将病毒培养物纯化,经蛋白检测及电镜观察确定成功构建猪SVV、PCV2嵌合病毒样颗粒(大小约30 nm).结果 表明,制备的猪SVV、PCV2嵌合病毒样颗粒疫苗可使试验猪同时产生针对猪SVV和PCV2的特异性抗体,充分显示出其作为一种针对猪场SVV和PCV2合并感染的安全有效疫苗的前景.

Lethal infection of wild birds with different subtypes of H5 viruses continuously occur. To investigate the genetic evolution and pathogenicity of H5 viruses in wild birds, we performed a detailed genetic and biologic analysis of 27 viruses, including H5N1, H5N2, H5N6, and H5N8 subtypes, that were responsible for avian influenza outbreaks in wild birds in China over the past decade. We found that these 27 viruses, bearing different clades/subclades of HA, were complicated reassortants and formed 12 different genotypes. Ten of the viruses tested were highly pathogenic in chickens, but showed distinct pathotypes in ducks and mice. Five of these 10 viruses, which were all from clade2.3.4.4, could bind human-type receptors. Our findings reveal the diversity of the genetic and biologic properties of H5 viruses circulating in wild birds and highlight the need to carefully monitor and evaluate the risks these viruses pose to animal and public health.

A H5N1 subtype avian influenza virus(AIV) A/palm-civet/Guangxi/26/2011(H5N1)(PC/GX/26/11(H5N1)) was isolated from palm civet in Southern China during the routine epidemiologic survey in 2011.The sequence data of hemagglutinin(HA) gene showed that the isolate was categorized as highly pathogenic AIV(HPAIV),with four typical HA cleavage site of-RRRR-,and belonging to clade 2.3.2.The phylogenic analysis indicated that PC/GX/26/11 shared 99.0% to 99.6% homology with the previously reported A/muscovyduck/Vietnam/LBM57/2011(H5N1) and A/Hubei/1/2010(H5N1) isolate.The pathogenicity test indicated that the virus was highly pathogenic in mice with a median lethal dose(MLD50) of 4.9 log10 EID50.This study also highlights the importance of continues surveillance of AIV in mammalian animals.

为研究H5N1亚型禽流感病毒(AIV)的抗药机制,本研究选取Clade2.3.4亚群中一株对金刚烷胺敏感的人源AIV A/Guangxi/1/2005(H5N1) (S-GX05),用抗流感病毒药物金刚烷胺对其进行定向诱导,筛选出一株抗药性病毒株,命名为R- A/Guangxi/1/2005 (R-GX05).通过全基因测序并与S-GX05全基因序列进行对比,结果显示S-GX05只在其M2蛋白中有一个氨基酸位点发生突变,即A30P；抗药性鉴定这两株病毒的半数药物抑制浓度(IC50)分别为0.9 μM和48.9 μM,表明R-GX05对金刚烷胺表现出一定程度的抗性.动物实验证实,这两株病毒对BALB/c小鼠的致病性基本一致,均表现出高致病性,其MLD50分别为4.7 log 10 EID50和5.0 log10 EID50,两株病毒在小鼠体内各组织脏器中的分布及增殖能力也基本相同.这些结果表明,S-GX05在药物压力下产生抗药性后,并未引起其它生物学特性的改变.A30P的发现为进一步从分子水平上研究H5N1亚型AIV的抗药机制及新型抗流感新药的研发奠定了基础.