Human mechanisms of virus persistence in an AAV-based mouse model of chronic HBV infection

项目总结 慢性乙肝病毒(HBV)感染与无效的T细胞反应有关，这种反应无法控制 病毒。虽然慢性乙肝患者T细胞功能障碍的确切机制尚不清楚，但在此之前 利用急性和慢性乙肝患者的血液和肝组织进行的研究已经确定了一些关键的 可能导致这种免疫反应不佳的免疫学机制。这些机制包括 肝脏自然杀伤(NK)细胞对乙肝病毒特异性T细胞的杀伤作用，这是一种普遍的耐受环境 表现为免疫抑制免疫细胞、细胞因子和代谢途径的肝脏，以及 通过抑制性受体信号通路和衰竭影响T细胞功能。乙肝病毒宿主的研究 慢性乙型肝炎的相互作用和新的治疗性免疫疗法的开发受到阻碍 由于缺乏慢性感染的生理学动物模型。一种新的复制乙肝病毒的小鼠模型 最近被描述的是基于腺相关病毒(AAV)介导的肝脏转导 乙肝病毒基因组，导致病毒持续复制和对乙肝病毒抗原的免疫耐受。与.相比 其他小鼠模型复制的乙肝病毒，AAV-乙肝模型具有重要的优势，包括生理 肝内免疫启动，技术简单性和重复性，外周T和B细胞对乙肝病毒的耐受性，以及 研究从肝脏中清除病毒的能力。使用这个模型，我们将检验乙肝病毒的假设 通过操纵免疫功能障碍的机制来促进疫苗治疗效果的提高 病毒清除。我们的总体方法将是将AAV-乙肝病毒转导与转基因小鼠相结合 和抗体介导的耗尽/阻断，以评估免疫细胞、细胞因子和调节的重要性 治疗性免疫后激发功能性CD8+T细胞反应和控制乙肝病毒的途径。 为了评估我们的假设，我们将实现三个具体目标。首先，我们将评估对乙肝病毒的抑制作用- NK细胞产生的特异性T细胞。其次，我们将定义调节细胞、细胞因子和代谢途径的作用。 第三，我们将评估T细胞抑制性受体功能和力竭。将从以下方面获得的知识 这项研究将在两个重要方面对该领域产生影响。首先，它将提供对 T细胞功能障碍与乙肝病毒迁延性的关系，为今后的研究奠定了坚实的基础 使用AAV-HBV模型更好地了解在人类身上观察到的病毒与宿主的相互作用。第二, 它将为治愈慢性乙肝病毒感染的潜在方法揭示新的免疫治疗靶点。

PROJECT SUMMARY Chronic hepatitis B virus (HBV) infection is associated with an ineffective T cell response that fails to control the virus. While the precise mechanism of T cell dysfunction in chronic hepatitis B is not well understood, prior studies using blood and liver tissue from acute and chronic HBV patients have identified a number of critical immunological mechanisms that may contribute to this poor immune response. These mechanisms include the killing of HBV-specific T cells by liver-resident natural killer (NK) cells, a general tolerogenic environment in the liver that is manifested by immunosuppressive immune cells, cytokines, and metabolic pathways, and the loss of T cell function through inhibitory receptor signaling pathways and exhaustion. The study of HBV-host interactions and the development of new curative immunotherapies for chronic hepatitis B have been hampered by the lack of physiological animal models for chronic infection. A new mouse model of HBV replication was recently described that is based on adeno-associated virus (AAV)-mediated transduction of the liver with the HBV genome, which leads to persistent virus replication and immune tolerance to HBV antigens. Compared to other mouse models of HBV replication, the AAV-HBV model has important advantages, including physiological intrahepatic immune priming, technical ease and reproducibility, peripheral T and B cell tolerance to HBV, and the ability to study virus elimination from the liver. Using this model, we will test the hypothesis that HBV therapeutic vaccine efficacy can be enhanced by manipulating mechanisms of immune dysfunction to promote viral clearance. Our general approach will be to combine AAV-HBV transduction with genetically modified mice and antibody-mediated depletion/blockade to evaluate the importance of immune cells, cytokines, and regulatory pathways for eliciting functional CD8+ T cell responses and controlling HBV following therapeutic immunization. To evaluate our hypothesis, we will carry out three specific aims. First, we will assess the inhibition of HBV- specific T cells by NK cells. Second, we will define the role of regulatory cells, cytokines, and metabolic pathways. Third, we will evaluate T cell inhibitory receptor function and exhaustion. The knowledge that will be gained from this research will impact the field in two important ways. First, it will provide new mechanistic insight into the relationship between T cell dysfunction and HBV persistence, and form a strong foundation for future studies using the AAV-HBV model to better understand the virus-host interactions that are observed in humans. Second, it will reveal new immunotherapeutic targets for potential approaches to cure chronic HBV infection.