Bactrian camel hepatitis E virus (HEV) is a novel HEV belonging to genotype 8 (HEV-8) in the Orthohepevirus A species of the genus Hepevirus in the family Hepeviridae. HEV-8 cross-transmits to cynomolgus monkeys and has a potential risk for zoonotic infection. Until now, neither a cell-culture system to grow the virus nor a reverse genetics system to generate the virus has been developed. To generate replication-competent HEV-8 and to establish a cell-culture system, we synthesized capped genomic HEV-8 RNAs by in vitro transcription and used them to transfect into PLC/PRF/5 cells. A HEV-8 strain, HEV-8M2, was recovered from the capped HEV-8 RNA–transfected cell-culture supernatants and subsequently passaged in the cells, demonstrating that PLC/PRF/5 cells were capable of supporting the replication of the HEV-8, and that a cell-culture system for HEV-8 was successfully established. In addition to PLC/PRF/5 cells, A549 and Caco-2 cells appeared to be competent for the replication, but HepG2 C3/A, Vero, Hela S3, HEp-2C, 293T and GL37 cells were incompetent. The HEV-8M2 strain was capable of infecting cynomolgus monkeys by an intravenous inoculation, indicating that HEV-8 was infectious and again carried a risk for zoonotic infection. In contrast, HEV-8 did not infect nude rats and BALB/c nude mice, suggesting that the reservoir of HEV-8 was limited. In addition, the replication of the HEV-8M2 strain was efficiently abrogated by ribavirin but not by favipiravir, suggesting that ribavirin is a drug candidate for therapeutic treatment of HEV-8-induced hepatitis. The infectious HEV-8 produced by a reverse genetics system would be useful to elucidate the mechanisms of HEV replication and the pathogenesis of type E hepatitis.

中文翻译：

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反向遗传系统产生双峰驼戊型肝炎病毒

双峰驼戊型肝炎病毒 (HEV) 是一种新型 HEV，属于Hepeviridae家族Hepevirus属的Orthohepevirus A种中的基因型 8 (HEV-8) 。HEV-8 可交叉传播给食蟹猴，并有潜在的人畜共患感染风险。到目前为止，既没有开发出培养病毒的细胞培养系统，也没有开发出产生病毒的反向遗传学系统。为了产生具有复制能力的 HEV-8 并建立细胞培养系统，我们在体外合成了加帽的基因组 HEV-8 RNA。转录并用它们转染到 PLC/PRF/5 细胞中。从加帽的 HEV-8 RNA 转染细胞培养上清液中回收 HEV-8 菌株 HEV-8M2，随后在细胞中传代，证明 PLC/PRF/5 细胞能够支持 HEV- 8、成功建立HEV-8细胞培养体系。除 PLC/PRF/5 细胞外，A549 和 Caco-2 细胞似乎具有复制能力，但 HepG2 C3/A、Vero、Hela S3、HEp-2C、293T 和 GL37 细胞无能力进行复制。HEV-8M2 菌株能够通过静脉接种感染食蟹猴，表明 HEV-8 具有传染性，并再次具有人畜共患感染的风险。相比之下，HEV-8 不会感染裸鼠和 BALB/c 裸鼠，表明 HEV-8 的储存库是有限的。此外，HEV-8M2 毒株的复制被利巴韦林有效地消除，但不能被法匹拉韦有效地消除，这表明利巴韦林是治疗 HEV-8 诱导的肝炎的候选药物。由反向遗传系统产生的传染性 HEV-8 将有助于阐明 HEV 复制的机制和 E 型肝炎的发病机制。