CTL EFFECTOR MECHANISMS IN ADENOVIRAL HEPATITIS

腺病毒肝炎中的 CTL 效应机制

• 批准号: 6177613
• 负责人: Dwain Louis Thiele
• 金额: $ 27.3万
• 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/6177613
• 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方面至关重要。这与CTL对非肝脏来源的同种异体或病毒感染的靶细胞的反应形成对比，在非肝源的靶细胞中，穿孔素依赖的机制起着更突出的作用。这一假说是基于初步研究表明，Fas/Fas配体依赖的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，CTL对肝细胞靶点的杀伤似乎在很大程度上依赖于Fas配体，而且穿孔素缺乏并不会显著削弱CTL对肝细胞靶标的杀伤作用。在拟议的研究中，我们将通过检测CTL介导的肝细胞靶标杀伤和病毒编码基因沉默在肝细胞中表达的机制来检验这一假说。我们将从腺病毒感染的小鼠中分离出肝内CTL，并直接检测杀伤腺病毒感染的肝细胞所使用的细胞杀伤效应机制。由腺病毒特异性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黏附分子和其他共刺激分子将被识别。我们将确定不同的CTL效应机制是否会沉默编码胞浆、细胞表面或分泌蛋白的腺病毒转导的外源基因。这一假说，即腺病毒编码的免疫调节蛋白对Fas依赖的效应机制的选择性调节将显著改变其他病毒编码基因的肝脏表达持续时间，这一假设将得到验证。这些研究将提供对CTL效应机制的深入了解，这些机制涉及清除肝脏中的病毒感染，并有可能指导增强和延长肝脏导向基因治疗表达的策略。