Funtional T-cell Failure in Chronic HCV Infection

根据我们在LCMV病毒感染模型和人类丙型肝炎病毒感染模型中的结果，病毒逃逸突变和与T细胞功能障碍和抑制相关的分子组合似乎是病毒持续存在的关键因素。重要的是，急性丙型肝炎病毒感染的数据表明，在疾病早期，丙型肝炎病毒感染可以在外周血单核细胞中引起可检测到的CD4和CD8T细胞反应，但在进展到慢性感染的人中，反应迅速下降。在肝脏中，仍然可以检测到反应，通常是几十年来，而且频率很高，但病毒仍在高水平持续存在。我们的总体假设是，T细胞功能障碍是未能控制丙型肝炎病毒感染的主要因素，通过结合小鼠和人类对T细胞功能障碍的研究，我们可以确定导致丙型肝炎病毒感染免疫控制不良的关键途径或免疫学缺陷。为了验证这一假设，我们建议通过在人类和小鼠身上进行相互告知的实验，进一步定义与不同水平的病毒控制相关的不同T细胞亚群。我们将根据LCMV的最新发现，确定在人的PBMC和肝脏来源的T细胞中使用丙型肝炎病毒特异性T细胞的抑制分子组合的功能和表达。与此同时，我们将通过详细区分不同功能障碍阶段和不同T细胞亚群中T细胞的转录图谱，进一步完善我们的小鼠模型。我们还将建立人类T细胞的转录图谱，这些数据集将为我们未来的研究方向指明方向。除了定义丙型肝炎病毒特异性T细胞的特性外，我们还将定义慢性丙型肝炎病毒感染时的肝脏环境如何导致T细胞功能障碍，从而导致病毒持续存在，例如通过T细胞抑制配体或调节细胞因子的表达。此外，我们还将研究丙型肝炎病毒特异性的CD4+T细胞，这些细胞对病毒控制同样重要，但研究的细节要少得多。这些研究将对了解丙型肝炎病毒的发病机制、指导预防性疫苗和免疫治疗干预的设计以及改进人类持续性病毒感染的一般模型至关重要。

ased on our results in the LCMV model of viral infection as well as in human HCV Infection it seems likely that viral escape mutations and a combination of molecules associated with T-cell dysfunction and inhibition are key contributors to viral persistence. Importantly, data in acute HCV infection indicate that HCV infection elicits both CD4 and CD8 T cell responses detectable in PBMC during early disease, but the responses decline quickly in persons who progress to chronic infection. In the liver, responses remain detectable, often for decades and at substantial frequencies, yet virus persists at high levels. Our overall hypothesis is that T-cell dysfunction is a major factor in failure to control HCV infection and that by combining both mouse and human studies of T cell dysfunction we can define key pathways or immunological defects underlying poor immunological control of HCV infection. To test this hypothesis we propose to further define the different subsets of T-cells associated with different levels of viral control with experiments in humans and mice informing each other. We will define the functional profile and expressions of a combination of inhibitory molecules using HCV-specific T-cells in human PBMC and liver derived T-cells based on recent findings in LCMV. In parallel we will further refine our murine model by differentiating in detail the transcriptional profiles of T-cells in different stages of dysfunction and different T-cell subsets. We will also establish transcription profiles of human T-cells and the datasets together will direct the future direction of our investigations. In addition to defining the properties of HCV-specific T-cells we will define how the liver environment in chronic HCV infection contributes to T-cell dysfunction and thus viral persistence, e.g. by the expression of T-cell inhibitory ligands or regulatory cytokines. In addition we will also investigate HCV-specific CD4+ T-cells that are equally critical for viral control but have been investigated in much less detail. These studies will be critical for understanding HCV pathogenesis, for guiding the design of prophylactic vaccines and immunotherapeutic interventions, but also for improved general model of persistent viral infections in humans.