Evolutionary Patterns of the Proviral gp90 V3 to V5 Regions of Equine Infectious Anemia Virus Associated with Immune Selection in Progressors and Nonprogressors  

作　　者：YUAN Xiu-fang ZHOU Tao HOU Shao-hua TU Ya-bin PENG Jin-mei WEN Jian-xin QIU Hua-ji WU Dong-lai TONG Guang-zhi 

机构地区：[1]National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences Harbin 150001, P.R.China [2]Institute of Animal Science and Veterinary Medicine, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, P.R. China [3]Shanghai Veterinary Research institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, P,R.China

出　　处：《Agricultural Sciences in China》2011年第1期126-135,共10页中国农业科学（英文版）

基　　金：supported by grants from the National High Technology R&D Program of China (863 Program,2001AA223041);the National Natural Science Foundation of China (30170706)

摘　　要：The aim of this study was to determine the genomic evolutionary pattern of virulent equine infectious anemia virus （EIAV） during persistent infection. The evolutionary dynamics of proviral genomes were examined by challenging an EIAV seronegative equine （pony 1） and three EIAV vaccinated equines （ponies 4, 7, and 8） with the Chinese virulent strain EIAV- L. Ponies 1 and 7 succumbed to disease and were called progressors, while ponies 4 and 8 lacked clinical symptoms and were considered nonprogressors. Sequences spanning the V3, V4, and V5 hyper-variable regions of the EIAV-L envelope gp90 gene were sequenced from each pony as evolutionary markers of the provirus. The proviral genome of the EIAV-L inoculum evolved during persistent infection and displayed different patterns between EIA progressors and nonprogressors. Inoculum-like variants were isolated from nonprogressors during persistent infection, but only from progressors during acute infection. Variant mutations from nonprogressors were dispersed throughout the sequenced region, while those from progressors were predominantly localized to V3. Humoral immunity and virus variant population selection analyses indicated that immune selection was positive in chronically infected progressors and weak in nonprogressors. In-frame stop codons were frequently localized to a defect ＂hot spot＂. The high number of defective variants in nonprogressors may promote disease survival.The aim of this study was to determine the genomic evolutionary pattern of virulent equine infectious anemia virus （EIAV） during persistent infection. The evolutionary dynamics of proviral genomes were examined by challenging an EIAV seronegative equine （pony 1） and three EIAV vaccinated equines （ponies 4, 7, and 8） with the Chinese virulent strain EIAV- L. Ponies 1 and 7 succumbed to disease and were called progressors, while ponies 4 and 8 lacked clinical symptoms and were considered nonprogressors. Sequences spanning the V3, V4, and V5 hyper-variable regions of the EIAV-L envelope gp90 gene were sequenced from each pony as evolutionary markers of the provirus. The proviral genome of the EIAV-L inoculum evolved during persistent infection and displayed different patterns between EIA progressors and nonprogressors. Inoculum-like variants were isolated from nonprogressors during persistent infection, but only from progressors during acute infection. Variant mutations from nonprogressors were dispersed throughout the sequenced region, while those from progressors were predominantly localized to V3. Humoral immunity and virus variant population selection analyses indicated that immune selection was positive in chronically infected progressors and weak in nonprogressors. In-frame stop codons were frequently localized to a defect ＂hot spot＂. The high number of defective variants in nonprogressors may promote disease survival.

关 键 词：equine infectious anemia virus PROVIRUS gp90 V3 PND immune selection 

分 类 号：S852.652[农业科学—基础兽医学] S852.4[农业科学—兽医学]