New insights into the functional diversity of the hepatic antiviral T cell response during hepacivirus infection in vivo

炎症性肝病如慢性丙型肝炎病毒（HCV）感染可进展为肝纤维化， 肝细胞癌（HCC）。肝脏T细胞免疫与肝脏疾病密切相关，因为T细胞不是 它仅对清除嗜肝病毒如HCV至关重要，但也可能导致肝损伤， 与疾病进展有关然而，功能上不同的CD 4+和CD 8 + T细胞亚群或 天然样T细胞，如自然杀伤T（NKT）细胞，在介导有效的抗病毒免疫应答中的作用，或 在炎症期间调节肝损伤还没有被很好地理解。因此，获得新的见解 肝T细胞亚群的功能生物学是开发HCV疫苗策略的先决条件， 治疗进展性肝病的免疫选择。 人类肝脏组织的有限获取和缺乏免疫能力的小动物模型阻碍了 肝脏抗病毒免疫机制的研究。然而，我们最近开发了一种具有免疫能力的 HCV相关病毒挪威大鼠肝炎病毒（NrHV）的小鼠模型，其具有显著的病毒学和 与人类HCV感染的免疫学相似性。这一进步现在允许深入的机械化 体内抗肝炎病毒免疫的研究。 我们对急性、慢性和继发性NrHV感染期间肝淋巴细胞亚群的初步分析显示， 显著诱导多种抗病毒1型T细胞应答和T细胞依赖性病毒清除。然而，在这方面， 我们还意外地观察到，肝CD 8 + T细胞和NKT细胞的亚群被极化， 2型免疫，并可能有助于免疫调节。在本提案中，我们将在这些基础上 初步数据和阐明不同的肝脏1型T细胞的功能特性和潜在的串扰 和分泌2型细胞因子的淋巴细胞亚群。具体来说，我们将使用高- 三维流式细胞术、体内功能性方法和/或转录组分析，以1）确定 不同病毒特异性效应子和记忆CD 8 + T细胞亚群的功能作用，2）确定病毒特异性效应子和记忆CD 8 + T细胞亚群的动力学和功能作用。 CD 4 + T细胞对病毒特异性CD 8 + T细胞产生和保护性免疫的影响，3）描述了 2型CD 8+和NKT细胞亚群的功能，并确定其对肝损伤，病毒特异性T细胞和 其他肝脏免疫细胞在感染的不同阶段。最后，我们的目标是将我们的主要发现从 将小鼠模型用于人类HCV患者。 我们的数据将为不同的肝脏1型和2型T细胞的作用和相互作用提供新的生物学见解。 和NKT细胞亚群在介导病毒清除、保护性免疫、组织病理或修复中的作用。 体内嗜肝病毒感染。

Inflammatory liver diseases such as chronic hepatitis C virus (HCV) infection can progress to liver fibrosis and hepatocellular carcinoma (HCC). Hepatic T cell immunity is closely linked to liver diseases since T cells are not only essential for the clearance of hepatotropic viruses like HCV but may also cause liver injury and contribute to disease progression. However, the specific role of functionally distinct CD4+ and CD8+ T cell subsets or innate-like T cells, such as natural killer T (NKT) cells, in mediating an effective antiviral immune response or regulating liver damage during inflammation are not well understood. Thus, gaining new insights into the functional biology of hepatic T cell subsets is a prerequisite for the development of HCV vaccine strategies and immunotherapeutic options for the treatment of progressive liver diseases. Limited access to human liver tissue and the lack of immune-competent small animal models has impeded studies of hepatic antiviral immune mechanisms. However, we have recently developed an immune-competent mouse model of an HCV-related virus, Norway rat hepacivirus (NrHV), which shares significant virological and immunological similarities with HCV infection in humans. This advance now allows for in-depth mechanistic studies of anti-hepaciviral immunity in vivo. Our initial analysis of hepatic lymphocyte subsets during acute, chronic and secondary NrHV infection revealed a significant induction of a diverse antiviral type 1 T cell response and T cell dependent viral clearance. However, we also made the unexpected observation that subsets of hepatic CD8+ T cells and NKT cells are polarized towards type 2 immunity and may contribute to immune-regulation. In this proposal, we will build on these preliminary data and elucidate the functional properties and potential crosstalk of distinct hepatic type 1 T cells and type 2 cytokine secreting lymphocyte subsets during NrHV infection. Specifically, we will use high- dimensional flow cytometry, in vivo functional approaches and/or transcriptome analysis to 1) define the functional role of different virus-specific effector and memory CD8+ T cell subsets, 2) determine the kinetic and impact of CD4+ T cells on the generation of virus-specific CD8+ T cells and protective immunity, 3) delineate the function of type 2 CD8+ and NKT cell subsets and define their impact on liver damage, virus-specific T cells and other hepatic immune cells during different stages of infection. Finally, we aim to translate our main findings from the mouse model to human HCV patients. Our data will provide novel biological insight into the role and interplay of distinct hepatic type 1 and type 2 T cell and NKT cell subsets in mediating viral clearance, protective immunity, tissue pathology or repair during a hepatotropic virus infection in vivo.