Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses; College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
International Corporation Laboratory of Agriculture and Agricultural Products Safety, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
Virol J. 2019 Aug 27;16(1):108. doi: 10.1186/s12985-019-1207-8.
Bovine leukemia virus (BLV) causes enzootic bovine leucosis and is widely spread worldwide, except several European countries, Australia and New Zealand. Although BLV is highly prevalent in China, information about the genetic diversity and evolutionary dynamics of BLV among Chinese dairy herds is still lacking. To determine the genetic variability of BLV, 219 cows from four cities of Ningxia province of China were screened for BLV infection by fluorescence resonance energy transfer (FRET)-PCR and sequencing, 16 selected positive samples were subjected to molecular characterization. Phylogenetic analysis using the neighbor-joining (NJ) method on complete sequences of envelope (env) gene of BLV obtained from China and those available in GenBank (representing BLV genotypes 1-10) revealed that those Chinese strains belonged to genotypes 4 and 6. Totally, 23 mutations were identified and 16 of them were determined to be unique mutations among Chinese strains. Alignment of the deduced amino acid sequences demonstrated six mutations in glycoprotein 51 (gp51) and three mutations in glycoprotein 30 (gp30) located in the identified neutralizing domain (ND), CD8 T cell epitope, E-epitope, B-epitope, gp51N12 and cytoplasmic domain of transmembrane protein. This study reported for the first time the BLV genotype 4 in China, and further studies are warranted to compare its immunogenicity and pathogenicity with other BLV genotypes.
牛白血病病毒（BLV）引起地方性牛白血病，广泛分布于世界各地，除了一些欧洲国家、澳大利亚和新西兰。尽管 BLV 在我国高度流行，但有关中国奶牛群中 BLV 的遗传多样性和进化动态的信息仍然缺乏。为了确定 BLV 的遗传变异性，我们通过荧光共振能量转移（FRET）-PCR 和测序对来自中国宁夏四个城市的 219 头牛进行了 BLV 感染筛查，对 16 个选定的阳性样本进行了分子特征分析。基于中国获得的 BLV 包膜（env）基因的完整序列和 GenBank 中可用的序列（代表 BLV 基因型 1-10），采用邻接法（NJ）对 BLV 进行系统进化分析，结果表明这些中国分离株属于基因型 4 和 6。总共鉴定出 23 个突变，其中 16 个被确定为中国分离株中的独特突变。推导的氨基酸序列比对显示，在确定的中和域（ND）、CD8 T 细胞表位、E 表位、B 表位、gp51N12 和跨膜蛋白胞质域中，糖蛋白 51（gp51）有 6 个突变，糖蛋白 30（gp30）有 3 个突变。本研究首次报道了中国的 BLV 基因型 4，有必要进一步研究其与其他 BLV 基因型的免疫原性和致病性。
