目的 用主要组织相容性复合物(MHC)抗原肽四聚体(Tetramer)流式细胞技术,分析乙型重型肝炎患者外周血中特异性细胞毒性T淋巴细胞(CTL)应答状况,并探讨其临床意义。方法 采用Tetramer流式细胞技术检测乙型重型肝炎患者外周血中受人类白细胞抗原Ⅰ类分子限制的三类特异性CD8^+CTL细胞数量;采用酶联免疫吸附斑点试验技术,测定经特异性乙型肝炎病毒(HBV)肽段诱导培养的特异性CTL表达膜内细胞因子IFNγ、TNFα、IL-4和IL—10等的水平;采用Promega CytoTox96非放射性细胞毒试验技术,测定经特异性HBV肽段诱导培养的特异性CTL杀伤靶细胞能力。结果 急性乙型重型肝炎组外周血中针对HBVcore18-27表位的特异性CTL数量高于慢性乙型重型肝炎组(P〈0.05),而低于急性乙型肝炎组(P〈0.05);急性乙型重型肝炎组表达干扰素γ和肿瘤坏死因子α较慢性乙型重型肝炎组高(P值均〈0.05);急性乙型重型肝炎组HBVcore18—27特异性CTL裂解靶细胞能力高于慢性乙型重型肝炎组(P〈0.05)。结论 急性乙型重型肝炎患者特异性CTL应答作用增强,而慢性乙型重型肝炎患者特异性CTI。应答缺乏。急性乙型重型肝炎患者外周血特异性CTL持续存在,可能与促进病毒清除等相关。
Objective To explore the role played by HBV antigen specific cytotoxic lymphocytes (CTLs) in severe hepatitis B patients. Methods Three kinds of HBV specific CD8^+ T cells responding to HBV core 18-27, polymerase 575-583 and envelope 335-343 specific CD8^+ T cells were searched with major histocompatibility complex (MHC)-peptide tetramer flow cytometry in the patients we studied. The cytokines produced by these specific CTLs such as IFN γ , TNF α, IL-4, IL-10 were detected using ELISPOT assays. Their ability to lyse target ceils was analyzed using a CytoTox96 Non-Radioactive Cytotoxicity Assay kit (Promega). Results The number of HBV core 18-27 specific CD8^+ T ceils was significantly higher in the peripheral blood of acute severe hepatitis B group patients than that in chronic severe hepatitis group (P 〈 0.05), but lower than that in the acute hepatitis B patients. The IFN y and TNF α levels of acute severe hepatitis B patients were both significantly higher than those in the chronic severe hepatitis group (P 〈 0.05). The ability to lyse target cells of HBV core 18-27 CTLs was also significantly higher in the acute severe hepatitis B group than that in the chronic severe hepatitis B group (P 〈 0.05). Conclusion The response to antigen stimulation was much higher in acute severe hepatitis B than in chronic severe hepatitis B patients. The specific CTLs persisted among the peripheral blood mononuclear cells in acute severe hepatitis B, which may be related to the viral clearance.