乙肝肝纤维化进程中CD161+CD4+T细胞的抗病毒、促炎、促纤维化功能及其机制研究

Persistent hepatitis B virus (HBV) infection causes chronic liver inflammation and liver fibrosis, and eventually progresses to liver cirrhosis and even hepatocellular carcinoma. In this process, it is critical that HBV-specific CD4+ T cells dysfunction and regulatory T cells (Treg) /helper T cell (Th) 17 cell subsets and Th1/Th2 cell subsets imbalance. The CD161 molecule is an important precursor marker of Th17 and is closely related to Th17/Th1 transformation and pro-inflammatory Treg cells. Simultaneously, CD161 may participates in viral hepatitis specific immune responses. Therefore, this project will study the expression and function of CD161 in the whole CD4+ T cell population in the process of chronic HBV infection. The preliminary results showed that increased CD161+CD4+ T cells have pro-inflammatory and pro-fibrotic functions. This project intends to use large cohorts of chronic HBV infected patients: 1) to observe the correlation between CD161+CD4+ T cells and clinical characteristics using cross-sectional study; 2) to explore the antiviral effects of CD161+CD4+ T cells using longitudinal study; 3) to uncover immune regulation and mechanisms of CD161+CD4+ T cells in inflammatory and fibrosis through RNA sequencing, chemotaxis assays, cell co-culture assays, etc. from the cytological and histological levels. We look forward to a better understanding of the role of CD161+CD4+ T cells in the immunoregulation in the progress of chronic HBV infection, hence enriching our acquisition about immune microenvironment of liver fibrosis, providing theoretical foundations and application basis for its clinical immunotherapy.

HBV持续感染引起慢性肝脏炎症和肝纤维化，并最终发展至肝硬化甚至原发性肝癌。在此过程中，HBV特异性CD4+T细胞功能衰竭及Treg/Th17亚群、Th1/Th2亚群的失衡至关重要。而CD161分子与多种CD4+T细胞亚群功能相关，且可能参与病毒性肝炎特异性应答。因此本项目将研究慢乙肝进程中CD161分子在整个CD4+T细胞群体中的表达及功能，预实验结果发现：CD161+CD4+T细胞表达增加，具有促炎、促纤维化功能。本次申请拟利用大型慢乙肝队列，以横断面和纵向研究研究CD161+CD4+T细胞水平与患者临床特征及抗病毒治疗疗效的关系为基础，以研究CD161+CD4+T细胞的抗病毒、促炎及促纤维化功能为主线，从细胞学及组织学水平通过转录组学、趋化试验、细胞共培养等途径深入阐述慢乙肝进程中CD161+CD4+T细胞对炎症及纤维化的免疫调控作用及机制，为免疫治疗肝纤维化提供理论基础。

肝纤维化的实质是免疫介导的持续肝损伤过程，CD4+ T 细胞及其亚群在乙肝肝纤维化进程中起重要调控作用，而CD161分子与多种CD4+T细胞亚群功能相关。本研究通过大型乙肝患者队列，利用流式细胞术等多种分子生物学手段，以横断面及纵向研究研究CD161+CD4+ T细胞在慢性HBV 感染不同阶段中的作用。结果发现，CD161+CD4+T细胞在慢乙肝和肝硬化患者中集聚且与慢乙肝病人临床特征密切相关，CD161+CD4+ T细胞数量的增加与HBeAg血清学转换有关。此外，与CD161-CD4+ T细胞相比，CD161+CD4+ T细胞产生更多的促炎细胞因子，包括IL-17和IFN-γ，并表达更高水平的肝脏归巢趋化因子受体，如CCR6, CXCR6和CX3CR1。值得注意的是，在HBV相关肝硬化中，共同表达IFN-γ和IL-17的CD161+CD4+ T细胞亚群显著富集。在体外共培养过程中，慢乙肝背景下的循环CD161+CD4+ T细胞可以通过IFN-γ/IL-23/IL-17轴调节肝星状细胞，表现出显著的促纤维化作用。本研究将丰富与完善肝纤维化的免疫调控网络，为临床乙肝肝纤维化的免疫诊治提供理论依据。