隐匿性乙型肝炎病毒感染分子机制的细胞及动物模型验证研究

Occult hepatitis B virus (HBV) infection (OBI) is an atypical form of HBV infection, which is defined as the persistence of HBV DNA, despite with undetectable HBsAg. Because the OBI is undetectable by routine regular immunoassays, it is a major source of HBV transmission by transfusion or organ transplantation. Although most of OBI cases are infected with HBV in an inactive or latent status, it is also a risk factor for HCC development and is a possible etiological factor in some case of cryptical liver diseases. Data from our previous study suggests secretion deficiency induced by characteristic viral gene mutations possibly play a key role in the occurrence of OBI, thus we'd like to perform further investigation for this hypothesis through current project. In this proposal, we aim to find specific viral mutation associated with OBI based on complete genomic sequencing of HBV. The in vitro and in vivo phenotypic characteristics of representative OBI strains will be systematically investigated in HBV-transfected hepatoma cell lines, HBV-susceptible HepaRG cell and human hepatocyte chimeric FRG mice. We expect the results of this study will confirm our hypothesis regarding the molecular mechanism of OBI occurrence. The interpretation of the OBI mechanism will provide more better understanding of underlying virological characteristic of HBV facilitate the improvement and development of strategies for prevention, diagnosis and treatment of HBV infection.

隐匿性乙型肝炎病毒感染（OBI），是乙型肝炎病毒（HBV）感染的一种特殊类型，表现为HBV表面抗原阴性而病毒核酸阳性。由于不能被常规手段检出，OBI感染者捐献的血液及器官是造成HBV经输血或经器官移植传播的重要潜在威胁；尽管病毒载量通常较低，OBI感染者仍具有罹患肝癌的风险，并可能是部分隐源性肝病的病因。在前期工作中，课题组发现特征性病毒基因变异导致的HBV分泌能力降低可能是OBI产生的重要原因，拟通过本研究进行系统性验证。本课题将从HBV全基因组角度对OBI感染者所携HBV进行全面分析，找出OBI特征性变异，并进一步在肝癌细胞转染模型，HepaRG细胞感染模型和FRG人肝嵌合小鼠感染模型中系统研究OBI毒株的体内外表型特征，以求证前期研究提出的关于OBI分子机制的科学假说。阐释OBI分子机制，对深入理解HBV的病毒学特征，HBV感染的预防、诊断及临床治疗策略的改进和提高具有重要指导价值。

血清表面抗原阴性而病毒核酸阳性的隐匿性乙型肝炎病毒感染(OBI)是乙型肝炎病毒(HBV)感染的一种特殊状态。OBI感染者不易被常规手段检出，其捐献的血液及成份血制品有造成HBV经血传播的潜在风险，尽管病毒载量通常较低，OBI感染者仍可能发展成为肝癌等终末期肝病，并可能是造成部分隐源性肝病的原因。本项目通过对流行病学研究中发现的OBI感染者所携HBV的序列分析，并在细胞和动物模型中对代表性OBI毒株的病毒功能表型进行了系统性研究，主要研究结果表明多数携带HBsAg变异的OBI毒株在细胞和动物模型中表现出HBsAg和HBV分泌能力下降的特点，揭示了病毒变异导致的抗原性改变和病毒分泌能力降低是OBI形成的重要病毒学原因。