Immune Costimulatory Molecules in HCV Pathogenesis

描述(由申请人提供)：T细胞介导的免疫反应在丙型肝炎病毒(HCV)感染的发病机制中发挥重要作用，但在这一过程中，新疗法(如siRNA)的分子基础和潜在的宿主靶点尚未得到很好的探索。我们假设，B7共刺激分子是激活和延长肝脏中丙型肝炎病毒特异性T细胞存活所必需的，因此是疾病发病机制的关键。两种互补的方法将被用来在新开发的肝脏特异性转基因小鼠模型中测试这一假设。首先，将产生两只在肝脏中表达结构或全长丙型肝炎病毒蛋白和CD86/B7.2分子的双基因转基因小鼠。将描述肝脏丙型肝炎病毒特异性和非特异性T细胞、NK细胞和巨噬细胞的特征，并将这些动物的肝损伤与单一转基因动物的肝损伤进行比较。为了进一步研究丙型肝炎病毒特异性T细胞是否可以在肝脏中启动，以及共刺激信号是否对疾病的启动和持续存在是必要的，我们接下来将产生在转基因诱导下表达肝内丙型肝炎病毒和CD86/B7.2分子的条件性双基因小鼠。由于丙型肝炎病毒特异性T细胞在这些小鼠体内是内在启动的，后一种模型更接近于丙型肝炎病毒感染者的情况。此外，还将通过流体动力基因传递技术研究CD80/B7.1和CD40在丙型肝炎发病机制中的作用。将致力于确定肝内干扰素和CC趋化因子的动态产生及其与丙型肝炎病毒诱导的肝损伤的相关性。这些研究将提供有关共刺激分子在丙型肝炎发病机制中的重要信息，并可能有助于设计未来针对阻断特定候选分子的策略。

DESCRIPTION (provided by applicant): T cell-mediated immune responses have long been proposed to play an important role in the pathogenesis of hepatitis C virus (HCV) infection; however, the molecular basis and potential host targets for novel therapeutics (e.g. siRNA) during this process are not well explored. We hypothesize that the B7 co-stimulatory molecules are required for activation and prolonged survival of HCV specific T cells in the liver and thus key to disease pathogenesis. Two complementary approaches will be used to test this hypothesis in newly developed, liver-specific transgenic mouse models. First, two bigenic transgenic mice that express the structural or full-length HCV proteins and CD86/B7.2 molecules in the liver will be generated. Hepatic HCV-specific and -nonspecific T cells, NK cells and macrophages will be characterized and liver injuries in these animals will be compared with those in single transgenics. To further examine whether HCV-specific T cells can be primed in the liver and whether co-stimulatory signals are necessary for disease initiation and perpetuation, we will next generate conditional bigenic mice that express intrahepatic HCV and CD86/B7.2 molecules upon transgene induction. As HCV-specific T cells are primed intrinsically in these mice, this latter model mimics more closely what occurs in HCV-infected persons. The functions of CD80/B7.1 and CD40 in HCV pathogenesis will also be studied through a hydrodynamic gene delivery technology. Effort will be directed at defining the kinetic production of intrahepatic IFN-( and CC chemokines and its correlation to HCV-directed liver injury. These studies would provide important information on co-stimulatory molecules in HCV pathogenesis and may aid in devising future strategies targeted at blocking specific candidates.