Resolution of Acute Hepatitis B Virus Infections in Chimpanzees

说明：目标。对于免疫系统如何解决急性乙型肝炎病毒（HBV）感染，提出了两种相互竞争的观点。B型肝炎病毒（HBV）感染。一种是基于先前在黑猩猩中的实验，假设细胞因子能够“非细胞溶解性地”治愈肝细胞中的所有病毒DNA，包括共价闭合环状病毒DNA（cccDNA），HBV的核转录模板;因此，感染的肝细胞的死亡对于治愈感染是不必要的。另一个由我们使用土拨鼠和鸭HBV模型的研究结果支持，提出cccDNA通过肝细胞死亡加上存活肝细胞的一轮或多轮增殖期间的损失来消除，以恢复肝脏质量。然而，黑猩猩实验中肝细胞破坏的数量尚未确定。而且，在所有三种模型中，尚不清楚肝细胞破坏和增殖的时间是否与cccDNA丢失相关。为了确定这一点，我们将使用一种创新的方法来量化HBV感染消退期间累积肝细胞增殖的时间进程。这种方法使用独特的病毒-宿主细胞DNA整合位点来标记单个细胞，并在感染过程中监测它们的命运。这些数据将与肝脏中病毒复制中间体和cccDNA的丢失、感染肝细胞百分比的变化和枯否细胞的活化、病毒血症的减少和免疫复合物中检测到的保护性抗体的出现以及肝细胞死亡的组织学指标相关。我们还将测量肝脏和血清中细胞因子表达的增加，以及免疫应答标志物肝脏基因表达的变化。累积起来，这些数据将提供在急性消退HBV感染期间在肝脏和血清中发生的事件的全面描述，并将使我们能够确定病毒清除的主要驱动力是破坏还是细胞因子介导的非细胞溶解性“治愈”感染的肝细胞。这种区别对于设计新的抗病毒疗法具有深远的意义。本案无关HBV是一个主要的全球性健康问题：> 3.5亿人患有慢性感染，导致25-50%的肝硬化终生风险，原发性肝癌风险增加，每年死亡人数高达1，000，000。我们的长期目标是将我们对解决急性HBV感染的理解应用于开发有效的慢性HBV感染新免疫疗法。

DESCRIPTION: Objectives. Two competing views for how the immune system resolves an acute hepatitis B virus (HBV) infection have been proposed. One, based on previous experiments in chimpanzees, postulates that cytokines are able to "non-cytolytically" cure hepatocytes of all viral DNA, including covalently closed circular viral DNA (cccDNA), the nuclear transcriptional template for HBV; thus, death of infected hepatocytes is unnecessary to cure the infection. The other, supported by the findings of our groups using the woodchuck and duck models of HBV, proposes that cccDNA is eliminated by a combination of hepatocyte death plus loss during one or more rounds of proliferation of surviving hepatocytes to restore liver mass. However, the amount of hepatocyte destruction in the chimpanzee experiments was not determined. And, in all three models, it is unclear if the timing of hepatocyte destruction and proliferation correlates with cccDNA loss. To determine this, we will use an innovative approach to quantify the time course of cumulative hepatocyte proliferation during resolution of HBV infection. This approach uses unique virus-host cell DNA integration sites to mark individual cells and to monitor their fate during the course of infection. These data will be correlated with the loss of viral replicative intermediates and cccDNA from the liver, changes in the percentage of infected hepatocytes and activation of Kupffer cells, decreases in viremia and the appearance of protective antibodies detected in immune complexes, as well as histological measures of hepatocyte death. We will also measure increases in cytokine expression in the liver and serum, as well as changes in liver gene expression for markers of the immune response. Cumulatively, these data will provide a comprehensive picture of the events occurring in the liver and serum during acute resolving HBV infection and will allow us to determine whether the primary driving force of viral clearance is destruction, or cytokine mediated non-cytolytic "curing", of infected hepatocytes. This distinction has profound implications for the design of new antiviral therapies. Relevance. HBV is a major worldwide health problem: >350 million people have chronic infections that result in a 25-50% lifetime risk of cirrhosis, increased risk of primary liver cancer and up to 1,000,000 deaths annually. Our long-term objective is to apply our understanding of the resolution of acute HBV infection to the development of effective new immunotherapies for chronic HBV infections.