CTL EFFECTOR MECHANISMS IN ADENOVIRAL HEPATITIS

腺病毒肝炎中的 CTL 效应机制

• 批准号: 6517459
• 负责人: Dwain Louis Thiele
• 金额: $ 28.97万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6517459
• 关键词: Adenoviridae; CD95 molecule; cell adhesion molecules; cellular immunity; cytolysins; cytotoxic T lymphocyte; hepatitis virus; histocompatibility antigens; infectious hepatitis; laboratory mouse; liver cells; pore forming protein; virus infection mechanism; virus receptors

We hypothesize that Fas/Fas ligand-dependent cytotoxic T lymphocyte (CTL) effector mechanisms are critically important in killing of virally infected hepatocytes. This contrasts with CTL responses to allogeneic or virally infected target cells of non- hepatic origin, where perforin-dependent mechanisms play a more prominent role. The hypothesis is based on preliminary studies indicating that defects in Fas/Fas ligand-dependent immune effector mechanisms greatly prolong in vivo expression of adenovirus encoded genes in the liver. Moreover, CTL killing of hepatocyte targets appears to be largely Fas ligand-dependent and is not dramatically impaired by perforin deficiency. In the proposed studies, we will test this hypothesis by examining mechanisms involved in CTL-mediated killing of hepatocyte targets and silencing of virally encoded genes expressed in hepatocytes. We will isolate intrahepatic CTL from adenovirus infected mice and directly examine the cytolytic effector mechanisms utilized in killing adenovirus-infected hepatocytes. The adhesion and other co-stimulatory molecules that are expressed by adenovirus-specific CTL and play a role in interactions with adenovirus-infected hepatocytes will be identified. We will determine whether different CTL effector mechanisms silence adenovirally transduced foreign genes encoding cytosolic, cell surface or secreted proteins. The hypothesis, that selective modulation of Fas-dependent effector mechanisms by adenovirus encoded immunomodulatory proteins will significantly alter the duration of hepatic expression of other virally encoded genes, will be tested. These studies will provide insights into CTL effector mechanisms involved in clearance of viral infections from the liver and have the potential to direct strategies that enhance and prolong expression of liver-directed gene therapy.

我们假设Fas/Fas配体依赖的细胞毒性T淋巴细胞（CTL）效应机制在杀死病毒感染的肝细胞中至关重要。这与对异体或病毒感染的非肝源靶细胞的CTL反应形成对比，在这些靶细胞中，穿孔依赖机制发挥更突出的作用。这一假设是基于初步研究表明，Fas/Fas配体依赖性免疫效应机制的缺陷极大地延长了腺病毒编码基因在肝脏中的体内表达。此外，肝细胞靶细胞的CTL杀伤似乎主要依赖于Fas配体，并且不会因穿孔素缺乏而显着受损。在拟议的研究中，我们将通过研究ctl介导的肝细胞靶点杀伤和肝细胞中表达的病毒编码基因沉默的机制来验证这一假设。我们将从腺病毒感染的小鼠中分离肝内CTL，并直接研究杀伤腺病毒感染的肝细胞的细胞溶解效应机制。通过腺病毒特异性CTL表达并在与腺病毒感染的肝细胞相互作用中发挥作用的粘附和其他共刺激分子将被确定。我们将确定不同的CTL效应机制是否沉默腺病毒转导的编码细胞质、细胞表面或分泌蛋白的外源基因。腺病毒编码的免疫调节蛋白对fas依赖性效应机制的选择性调节将显著改变其他病毒编码基因在肝脏表达的持续时间，这一假设将被验证。这些研究将深入了解CTL效应物清除肝脏病毒感染的机制，并有可能指导增强和延长肝脏定向基因治疗表达的策略。