qAnti-HBc预测HBeAg血清学转换的机制探索：T-bet(+)B细胞的关键作用

The achievement of HBeAg seroconversion and sustained immune control is a satisfactory endpoints of antiviral therapy in chronic hepatitis B. Several studies have shown that baseline level of the quantification of Anti-HBc (qAnti-HBc) was an independent predictor of HBeAg seroconversion after antiviral treatment, but the potential immunological mechanism have not been clarified. Our previous work found that the frequency of T-bet(+)B cells was positively correlated with qAnti-HBc, suggesting that T-bet(+)B cells may be involved in the immune regulation of HBeAg seroconversion. We aimed to verify the proposed scientific hypothesis by researches of clinical cohorts and in vivo and in vitro tests. Firstly, we verify the correlation between the frequency of T-bet(+) B cells and qAnti-HBc, the distribution and surface markers of T-bet(+)B cells in hepatitis B patients by flow cytometry in the clinical cohorts. Thereafter, we study the effect of T-bet on cytokine secretion and antibody productionin of B cells in vitro. Finally we establish a chronic HBV infection model in T-bet deletion of B cells mice to verify the key role of T-bet(+)B cells in virus clearance in chronic HBV infection. This study will help to provide clues to explore the immunoregulation on HBeAg seroconversion in chronic HBV infection.

实现HBeAg血清学转换和持久免疫控制，是慢性乙型肝炎抗病毒治疗的满意终点。多个研究证明基线qAnti-HBc能独立预测抗病毒治疗诱导的HBeAg血清学转换，但其免疫学机制尚未阐明。我们前期工作发现T-bet(+)B细胞频数与qAnti-HBc成正相关关系，推测T-bet(+)B细胞可能参与HBeAg血清学转换的免疫调节。本项目拟从临床研究队列，体内及体外三个层面验证我们的科学假说，首先通过临床队列运用流式细胞术验证T-bet(+)B细胞频数与qAnti-HBC的相关性及其在慢性乙肝患者的分布特点和表面标志的特征；接着通过体外实验研究T-bet对B细胞细胞因子分泌及抗体生成的影响；最后运用B细胞特异性T-bet敲除小鼠建立HBV慢性感染模型，通过体内实验证实T-bet(+)B细胞在慢性HBV感染中抗病毒的关键作用，希冀此研究为探索慢乙肝患者HBeAg血清学转换的免疫调节机制提供重要线索。

通过治疗实现HBeAg血清学转换和持久免疫控制，是慢性乙型肝炎抗病毒治疗满意的终点。达到该治疗终点的预测因素及免疫机制尚不明确。本项目通过临床研究队列进一步探索qAnti-HBc与抗病毒治疗应答尤其是HBeAg血清转换的关系，构建了基于qAnti-HBc水平的HBeAg血清学转换的预测模型；通过ELISA的方法检测其血清中anti-HBc定量及其亚型；然后通过肝内组化染色HBcAg，分析anti-HBc产生的免疫学机制。通过流式细胞术检测相关免疫细胞表型、活化功能和HBV特异性T细胞频数，探索anti-HBc水平与免疫细胞表型和功能的相关性。结合体外实验和和动物模型研究，验证了本项目的科学假说：qAnti-HBc水平可用于预测抗病毒治疗应答并与持久免疫控制有关，anti-HBc水平反映了机体针对HBcAg特异性B细胞和CD8+ T细胞的免疫激活，anti-HBc也可以直接介导抗HBV免疫反应，从而控制HBV感染。