丙型肝炎病毒特异性细胞毒性T淋巴细胞活性研究

Activity of HCV-specific cytotoxic T lymphocytes in chronic hepatitis C

目的 阐明丙型肝炎病毒 (HCV)特异性细胞毒性T淋巴细胞 (CTL)在慢性丙型肝炎病毒感染中的作用。方法 用标准铬释放法 (以从患者肝组织或外周血单个核细胞中经选择性克隆扩增后的CD8+细胞为效应细胞 ,经EB病毒转染的自身B淋巴母细胞为靶细胞 ,由能表达HCV1型核心区基因的重组痘苗病毒作为转导载体 )对 62例慢性丙型肝炎患者肝组织及外周血单个核细胞(PBMC)中的HCV特异性CTL活性 (HCV CTL)进行检测 ,8例非HCV感染的肝病患者作为对照。结果 62例慢性丙型肝炎患者中 ,共有 2 8例 ( 4 6.7%)肝组织中检测出HCV CTL活性 ,但HCV CTL在PBMC中未检出。对照组患者肝组织及PBMC中均未检出。 5例非HCV1感染的丙型肝炎患者检测出针对HCV1型表位的HCV CTL。HCV CTL阳性的丙型肝炎患者血清丙氨酸转氨酶 (ALT)、天门冬氨酸转氨酶 (AST)水平及肝组织活动指数均明显高于HCV CTL阴性的患者 ,而其血清HCVRNA水平则显著低于后者 (P <0 .0 1)。结论 1.HCV CTL主要存在于肝组织内 ;2 .存在型交叉性HCV CTL ;3 .HCV CTL活性阳性的患者较HCV CTL活性阴性者具有较高的疾病活动度及较低的病毒血症水平 ;4 .HCV特异性CTL在丙型肝炎的发病机制及疾病控制中起重要作用。

Objective To define the role of HCV-specific cytotoxic T lymphocytes (CTL) in chro-nic hepatitis C virus (HCV) infection. Methods HCV-specific CTL activity (HCV-CTL) was assessed in the liver and peripheral blood cells in 62 patients with chronic hepatitis C and 8 non-HCV-infection controls by using bulk-expanded liver/peripheral blood mononuclear lymphocytes (PBMC)-derived CD8+ cells as effector cells, EBV-transformed B cells as autologous target cells and recombinant vaccinia vectors expressing various regions of the HCV genome as transduction vector, in a standard chromium release assay. Results HCV-CTL activity was detected from the liver in 28 of the 60 patients (46.7%), but not from PBMC. CTL activity could not be detected from the liver and PBMC in all non-HCV-infection controls. Five patients with non-type 1 HCV infection were found to have HCV-specific CTL activity against HCV type 1 epitope. Compared with the patients without detectable HCV-specific CTL activity based on our assay, those exhibiting CTL activity had higher serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, higher histologic activity indices and lower levels of HCV RNA (all P< 0.01). Conclusions 1) HCV-specific CTL is found mainly in the liver rather than in peripheral blood, suggesting a tissue-specific localization with HCV-specific CTL; 2) Cross-genotype CTL activity exists; 3) Patients with HCV-specific CTL activity in the liver have more active liver disease and lower levels of viremia; 4) Cellular immune response mediated by HCV-specific CTL plays an important role in the pathogenesis and control of hepatitis C virus infection.