乙型肝炎病毒核衣壳内DNA诱导固有免疫应答机理的研究

Hepatitis B virus (HBV) is a major risk factor of liver cirrhosis and hepatocellular carcinoma. Currently approved antiviral drugs cannot cure HBV infection. Elimination of HBV is mainly dependent on the HBV-specific cytotoxic CD8+ T lymphocytes mediated cytolytic effect that also causes hepatic inflammation， which results in liver fibrosis as well as liver cirrhosis. Thus, non-cytolytic elimination can be an ideal strategy to cure HBV infection. Recently, it has been reported that host innate immune system could be activated by HBV and induce cytokines such as interferon (IFN) , which may contribute to non-cytolytic elimination of HBV. Our previous study showed that, in an immortalized mouse hepatocyte-AML12HBV10 cell, viral DNAs inside the structurally loosened HBV nucleocapsids (NCs) could be recognized by host DNA sensor and induces innate immune response to limit HBV replication. However, how the HBV DNA inside NC activates innate immune response in human hepatocytes or in human liver is unclear. .Therefore, in this grant application, we propose to investigate HBV-NC associated DNA induction of innate immune response in human hepatocyte cell lines that express structurally loosened HBV-NC. These studies will provide the rationale for non-cytolytic elimination of HBV by understanding the signaling pathway of innate immune response.

乙肝病毒(HBV)是引起肝硬化和原发性肝细胞癌的主要危险因子之一。目前尚无治愈HBV感染的药物。机体主要依赖适应性免疫应答清除HBV感染, 但同时导致感染靶细胞损伤并引起肝组织炎症。因此，非靶细胞损伤性清除HBV是治疗HBV感染的最理想的治疗方法。研究表明，HBV可激活固有免疫应答并诱导干扰素（IFN）等细胞因子，而此时诱导的IFN可能与非靶细胞损伤性清除HBV有紧密联系。我们的研究表明，在AML12HBV10细胞（鼠源肝细胞）中HBV核衣壳（NC）结构的松弛性变化可使NC内DNA暴露于NC外环境并被宿主DNA受体所识别后诱导固有免疫应答，继而抑制HBV表达。但是在人源肝细胞或肝组织中HBV DNA激活固有免疫应答的机制尚不清楚。本研究拟利用表达松弛型HBV-NC的HBV突变株在人源肝细胞株中深入研究HBV-NC内 DNA激活固有免疫应答的机制，为非靶细胞损伤性治疗HBV感染提供理论依据。

前期研究表明，在AML12HBV10细胞（鼠源肝细胞）中HBV核衣壳（NC）结构的松弛性变化可使NC内DNA暴露于NC外环境并被宿主DNA受体所识别后诱导固有免疫应答，继而抑制HBV表达。但是在人源肝细胞或肝组织中HBV DNA激活固有免疫应答的机制尚不清楚。本研究中拟利用表达松弛型HBV-NC的HBV突变株在人源肝细胞株中深入研究HBV-NC内 DNA激活固有免疫应答的机制，为非靶细胞损伤性治疗HBV感染提供理论依据。.为此，研究中首先构建了表达HBV 野生型和HBcI126A突变株的质粒，并验证了其有效性。继而在可表达HBV 野生型和HBc I126A 突变株病毒颗粒的人源肝细胞中建立了稳定细胞株，为j筛查参与HBV感染后参与固有免疫应答的宿主因子，如cGAS等基因的表达奠定了基础。