Cellular Immune Response to Acute HCV Infection

项目1的主要目标是确定与病毒持续相关的丙型肝炎病毒特异性CDS T细胞功能损害的机制。虽然在丙型肝炎病毒免疫逃避中会发生T细胞表位内的病毒逃逸突变，但在慢性感染者中，相当大比例的CDS T细胞识别不显示逃逸突变的丙型肝炎病毒表位。因此，针对非逃逸表位的CDS细胞的功能损害很可能是丙型肝炎病毒持续存在的另一个重要因素。我们认为，对清除了丙型肝炎病毒感染的患者和没有清除丙型肝炎病毒感染的患者之间以及识别抗原表位的T细胞发生替换和没有发生替换的患者之间的丙型肝炎病毒特异性CDS T细胞表型和功能的全面比较分析，将揭示T细胞无应答与病毒持久性相关的特定分子和细胞机制。具体地说，我们的目标是)进行一系列体外功能分析，评估各种先前鉴定的表型的丙型肝炎病毒特异性CDS T细胞产生相关效应细胞因子和执行杀伤功能的能力；2)通过过继转移到已建立的NOD/SCID/-/-系统中，建立和鉴定体内CJ毒性淋巴细胞(CTL)试验，用于分析四聚体+丙型肝炎病毒特异性CDS细胞的功能。这将使我们能够直接分析针对潜在相关细胞膜受体的抗体和/或细胞因子在体内对人丙型肝炎病毒特异性CDS T细胞的功能影响。在这个新的体内系统中，通过使用特定的拮抗剂抗体，CDS T细胞无应答的候选分子决定因素将被询问。在这个新的体内系统中，来自患者的人T细胞过继转移到接受性免疫缺陷小鼠。这次询问的结果将直接与慢性丙型肝炎病毒感染的免疫治疗相关，并加强对与持续感染相关的T细胞损伤的了解。项目2对体液免疫反应的研究结果将被整合，以扩大对人类对丙型肝炎病毒的体液免疫反应和细胞免疫反应之间相互作用的知识。我们 已经证明，我们可以获得这项研究所需的关键样本，并将能够对急性丙型肝炎的获得性免疫反应进行独特的纵向研究。

The primary objective of Project 1 is to define the mechanisms of functional impairment of HCV-specific CDS T cells associated with viral persistence. While viral escape mutations within T cell epitopes occur in HCV immune evasion, a significant proportion of CDS T cells in chronically infected subjects recognize HCV epitopes that do not demonstrate escape mutations. It is thus likely that functional impairment of CDS cells specific for nonescaped epitopes is an additional important factor in HCV persistence. We propose that a comprehensive comparative analysis of HCV-specific CDS T cell phenot5TDe and function among patients who clear HCV infection versus those who do not, and between T cells recognizing epitopes that undergo substitution and those that do not will reveal specific molecular and cellular mechanisms of T cell unresponsiveness relevant to viral persistence. Specifically, we aim l)To perform a set of in vitro fiinctional analyses assessing the capacity of HCV specific CDS T cells of various previously characterized phenotj^jes to produce relevant effector cj^okines and to perform killer functions and 2)To develop and characterize an in vivo cj^otoxic lymphocyte (CTL) assay for functional analysis of tetramer+ HCV specific CDS cells using adoptive transfer into an established NOD/SCID/--/- system. This will allow us to directly analyze the in vivo functional effects of antibodies and/or cytokines targeted at potentially relevant cell membrane receptors on human HCV specific CDS T cells. Using specific antagonist antibodies, candidate molecular determinants of CDS T cell unresponsiveness will be interrogated in this novel in vivo system in which human T cells from patients are adoptively transferred into receptive immunodeficient mice. Outcomes of this interrogation will have direct translational relevance to the immunotherapy of chronic HCV infection as well as enhancing understanding of T cell impairment associated with persistent infection. Results of studies of humoral immune responses from Project 2 will be integrated to expand knowledge of the interplay between humoral and cellular immune responses to HCV in humans. We have already demonstrated that we can obtain the critical specimens required for this investigation and will be able to conduct unique longitudinal studies of adaptive immune responses in acute HCV.