中文摘要：

为研究马传染性贫血病毒（EIAV）驴白细胞弱毒疫苗EIAVDLV121的S2基因在马体内的变异规律,本研究选用4匹成年马,其中2匹（#1、#2）接种EIAVDLV121,另外2匹作为对照。免疫后监测马体温、血小板含量以及病毒载量结果显示,免疫马未出现马传染性贫血体征。通过RT-PCR方法检测病毒S2基因在感染马体内不同时期的基因序列,结果显示,免疫马体内EIAVDLV121 S2蛋白的突变主要发生在氨基酸第17位、22位、39位、41位、51位和55位。另外,#1马免疫后70 d以及#2马免疫后第14 d和第28 d检测疫苗毒S2蛋白序列与EIAVDLV121亲缘关系较近,而#1马免疫后第42 d、第112 d和第140 d的疫苗毒S2蛋白序列与EIAVDLV121的致病性亲本强毒株EIAVLN40亲缘关系最近。本研究结果有助于对EIAV及EIAV疫苗株在马体内感染进程的研究。

英文摘要：

The variation of S2 gene of the equine infectious anemia virus（EIAV） attenuated vaccine adapted to cultivated donkey leukocytes was investigated by analysing virus replicated in experimentally infected horses.Two horses,#1 and #2,were inoculated with EIAVDLV121.Body temperature,viral RNA copy and platelet count of these horses were monitored for 6 months.Furthermore,the S2 gene of EIAVDLV121 was amplified by RT-PCR from plasma at different time points and sequenced.Results of sequence analysis showed that there were 6 consentaneous mutations in the S2 gene,which caused substitutions of translated amino acid residues in EIAV replicated in the hosts.In addition,the S2 genes amplified at the 70th day from horse #1 and at the 14th and 28th day from horse #2 had the highest homology to the consensus sequence of EIAVDLV121 S2 gene before inoculation.On the other hand,the S2 gene sequences of samples at the 42nd,122nd,and 140th day from horse #1 appeared reduced divergence to the consensus S2 sequence of pathogenic strain EIAVLN40,which was the parental strain of EIAVDLV121.Our data on the EIAV S2 gene variation in vivo facilitate the studies on procedures of infection of pathogenic EIAV and vaccine strains.