Department of Internal Medicine, Affiliated Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China.
J Med Virol. 2013 Apr;85(4):627-35. doi: 10.1002/jmv.23504. Epub 2013 Jan 30.
Rabbit hepatitis E virus (HEV) in China may represent a novel HEV genotype, although no consensus has been reached. It is unclear whether the ORF2 capsid protein containing the immunodominant epitopes from rabbit HEV differs from those of human HEV. In this study, 661 bile samples collected from domestic rabbits in Jiangsu province, eastern China were amplified by RT-nPCR using a set of HEV universal ORF2 primers. All 42 (6.4%) positive PCR products were sequenced. Phylogenetic analysis using the ORF2 sequences of 557 bp in length showed the Jiangsu isolates were separate from HEV genotypes 1, 2, 3, 4, avian HEV and rat HEV, and clustered together with rabbit HEV sequences. These 42 isolates were divided into five branches including two newly identified in the present study. Comparison with rabbit HEV sequences from China available in GenBank, using a 298 bp ORF2 segment, showed these sequences clustered together into a unique rabbit HEV clade, and were divided into eight sub-branches with high genetic heterogeneity. In addition, 267 serum samples collected from domestic rabbits, serial serum samples from two rhesus monkeys experimentally infected with HEV genotype 1 or 4, and serial serum samples from two New-Zealand rabbits infected experimentally with rabbit HEV were tested simultaneously by EIA using recombinant truncated ORF2 capsid proteins derived from rabbit and human HEV. The virtually identical results obtained suggest that rabbit and human HEV ORF2 antigens contain very similar immunodominant epitopes. All these data are helpful to identify the biological characteristics of the newly identified rabbit HEV.
中国的兔型肝炎 E 病毒 (HEV) 可能代表一种新型的 HEV 基因型，尽管尚未达成共识。目前尚不清楚来自兔型 HEV 的含有免疫优势表位的 ORF2 衣壳蛋白是否与人类 HEV 的 ORF2 衣壳蛋白不同。在这项研究中，使用一组 HEV 通用 ORF2 引物，通过 RT-nPCR 扩增了来自中国东部江苏省的 661 份家兔胆汁样本。所有 42 个（6.4%）阳性 PCR 产物均进行了测序。使用 557bp 长的 ORF2 序列进行的系统发育分析表明，江苏分离株与 HEV 基因型 1、2、3、4、禽 HEV 和鼠 HEV 分开，并与兔 HEV 序列聚类在一起。这 42 个分离株分为五个分支，其中两个是本研究新鉴定的。与 GenBank 中可获得的来自中国的兔 HEV 序列相比，使用 298bp 的 ORF2 片段，这些序列聚集在一起形成一个独特的兔 HEV 分支，并分为 8 个子分支，具有高度遗传异质性。此外，同时使用来自兔和人 HEV 的重组截短 ORF2 衣壳蛋白，通过 EIA 检测了从家兔中收集的 267 份血清样本、2 只感染 1 型或 4 型 HEV 的恒河猴的系列血清样本以及 2 只感染兔 HEV 的新西兰兔的系列血清样本。通过实验感染获得的结果几乎相同，表明兔和人 HEV ORF2 抗原含有非常相似的免疫优势表位。所有这些数据有助于鉴定新鉴定的兔 HEV 的生物学特征。
