A Mouse Model for Studying the Clearance of Hepatitis B Virus In Vivo Using a Luciferase Reporter

Hepatitis B virus(HBV) infection remains a global problem, despite the effectiveness of the Hepatitis B vaccine in preventing infection. The resolution of Hepatitis B virus infection has been believed to be attributable to virus-specific immunity. In vivo direct evaluation of anti-HBV immunity in the liver is currently not possible. We have developed a new assay system that detects HBV clearance in the liver after the hydrodynamic transfer of a reporter gene and over-length, linear HBV DNA into hepatocytes, followed by bioluminescence imaging of the reporter gene (Fluc). We employed bioluminescence detection of luciferase expression in HBV-infected hepatocytes to measure the Hepatitis B core antigen (HBcAg)-specific immune responses directed against these infected hepatocytes. Only HBcAg-immunized, but not mock-treated, animals decreased the amounts of luciferase expression, HBsAg and viral DNA from the liver at day 28 after hydrodynamic infection with over-length HBV DNA, indicating that control of luciferase expression correlates with viral clearance from infected hepatocytes.

乙型肝炎病毒（Hepatitis B virus, HBV）感染仍是全球性公共卫生难题，尽管乙型肝炎疫苗在预防感染方面效果确切。既往认为，乙型肝炎病毒感染的清除有赖于病毒特异性免疫应答，但目前尚无法在活体中直接评估肝脏内的抗HBV免疫状态。本研究开发了一种新型检测系统：将报告基因与超长线性HBV DNA通过水动力转染导入肝细胞后，可检测肝脏内的病毒清除情况，随后通过生物发光成像对报告基因（荧光素酶Fluc）进行检测。我们利用HBV感染肝细胞中荧光素酶表达的生物发光检测，定量分析针对受感染肝细胞的乙型肝炎核心抗原（Hepatitis B core antigen, HBcAg）特异性免疫应答。实验结果显示，仅经HBcAg免疫的动物，在接受超长HBV DNA水动力感染后的第28天，其肝脏内的荧光素酶表达量、乙型肝炎表面抗原（HBsAg）与病毒DNA水平均显著下降，而模拟处理组未出现此类变化，这表明荧光素酶表达的调控与受感染肝细胞内的病毒清除密切相关。