Genetic viral and host adaptations to breach species barriers of HCV

描述(申请人提供)：丙型肝炎仍然是一种全球流行病。至少有1.3亿人患有慢性丙型肝炎，这是由丙型肝炎病毒(丙型肝炎病毒)引起的，丙型肝炎病毒是黄病毒家族的一种阳性单链RNA病毒。丙型肝炎病毒有很高的慢性感染倾向。如果不进行治疗，慢性丙型肝炎病毒携带者会发展成严重的肝病，包括纤维化、肝硬变和肝细胞癌。抗病毒治疗只有部分有效，费用昂贵，而且往往耐受性差。目前尚不存在预防或治疗丙型肝炎病毒的疫苗。由于缺乏合适的小动物模型，更有效的治疗方法和疫苗的开发一直受到阻碍。基于我们之前观察到的CD81和occludin(OCLN)包括使小鼠细胞允许体外进入丙型肝炎病毒所需的最低人类因素集，我们尝试通过遗传方法使小鼠人源化。我们证明了这两个人类基因的表达足以使完全免疫能力的近交系小鼠感染丙型肝炎病毒。我们提供了全面的初步数据，证明先天和获得性免疫反应的组合限制了这些小鼠中持续的丙型肝炎病毒复制。我们证明，在表达人CD81和OCLN的小鼠中钝化抗病毒免疫会导致低水平的病毒血症，持续数周。这一观察结果为使丙型肝炎病毒在条件性近交系小鼠中高效复制的可行性提供了关键证据。我们现在建议通过利用丙型肝炎病毒显著的遗传可塑性，系统地克服丙型肝炎病毒跨物种生长的额外障碍。我们的研究最终将导致一种完全免疫活性的丙型肝炎病毒感染小鼠模型，我们将使用该模型来研究丙型肝炎病毒相关的肝病。支持整个丙型肝炎病毒生命周期的近交系小鼠模型为从基因上剖析体内丙型肝炎病毒感染打开了前所未有的机会，并为测试和优先选择候选药物和疫苗提供了一个重要的临床前平台。

DESCRIPTION (provided by applicant): Hepatitis C remains a global epidemic. At least 130 million individuals suffer from chronic hepatitis C, which is caused by hepatitis C virus (HCV) - a positive sense, single-stranded RNA virus of the Flaviviridae family. HCV has a high propensity for establishing chronic infection. If untreated chronic HCV carriers can develop severe liver disease including fibrosis, cirrhosis and hepatocellular carcinoma (HCC). Antiviral treatment is only partially effective, costly and often poorly tolerated. A prophylactic or therapeutic vaccine for HCV does not exist. Development of more effective therapies and vaccines has been hampered by the lack of a suitable small animal model. Building on our previous observation that CD81 and occludin (OCLN) comprise the minimal set of human factors required to render mouse cells permissive for HCV entry in vitro, we attempted murine humanization via a genetic approach. We demonstrated that expression of the two human genes is sufficient to allow HCV infection of fully immunocompetent inbred mice. We provide comprehensive preliminary data demonstrating that a combination of innate and adaptive immune responses restricts persistent HCV replication in these mice. We demonstrate that blunting antiviral immunity in mice expressing human CD81 and OCLN results in low level, viremia over several weeks. This observation provides critical evidence for the feasibility of adapting HCV to replicate efficientlyin conditioned inbred mouse strain. We now propose to systematically overcome additional blocks to interspecies growth of the HCV by exploiting HCV's remarkable genetic plasticity. Our studies will ultimately lead to a fully immunocompetent mouse model for HCV infection, which we will use to study HCV-associated liver disease. An inbred mouse model that supports the entire HCV life-cycle opens unprecedented opportunities to genetically dissect HCV infection in vivo and provides an important preclinical platform for testing and prioritizing drug and vaccine candidates.