人脐血来源树突细胞抗乙型肝炎病毒细胞免疫的体外实验研究

A study on the anti-HBV effect of dendritic cell from human mbilical cord blood

目的借助DC的强大抗原呈递能力，使其负载HBsAg后以激活HBsAg特异性的CTL，从而探索一种可有效活化讥体抗HBV细胞免疫的免疫方式。方法从健康产妇分娩的胎儿脐血中分离出单个核细胞，在细胞因子组合的作用下诱导出DC，于体外负载HBsAg后，激活自体T细胞成CTL，于体外培养环境下检测其对表达HBsAg的靶细胞HepG2-S的杀伤效应。结果人脐血来源的单个核细胞可在多种细胞因子的作用下，被诱导为DC。DC在负载HBsAg后可于体外活化HBsAg特异性的CTL。效应细胞为负载HBsAg的DC活化脐血单个核细胞，靶细胞分别为不表达和表达HBsAg的HepG2，当效应细胞和靶细胞比为1：1时出现最大的杀伤效率，CTL对靶细胞的杀伤率分别为（16．36±6．42）％和（78．09±9．66）％，差别有统计学意义（P〈0．01）。结论健康人脐血来源的DC，具有较强的抗原呈递功能，可在体外激活产生HBsAg特异性CTL，在表达HBsAg的靶细胞模型上可观察到一定杀伤效果，为人脐血来源DC用于抗HBV治疗进行了有益的探索。

Objectives Regarding the strong antigen-presenting abilities of dendritic cells （DC）, this study was carried out based on the induction and proliferation of DC derived from human umbilical cord blood; the anti-HBV effect of cytotoxicity T lymphocytes （CTL） activated by those DC pulsed with HBsAg was also carded out to explore a new way to activate the HBsAg-specific CTL. Methods Cord blood was collected from the cord veins of normal placentae after Cesarean sections, from which cord blood mononuclear cells （CBMC） were separated through density gradient centdfugation. The CBMC were cultured in RPMI 1640 with a cytokine cocktail. Pulsed with HBsAg, the DC were prepared to activate the HBsAgspecific CTL among the CBMC. The cytotoxic effect of CBMCs activated by the DC primed with HBsAg was assayed through the killing of those HepG2-S target cells. Results Typical DC could be induced from CMBC cultured with a cytokine cocktail. DC pulsed by HBsAg activated HBsAg-specific CTL, which killed the target HepG2-S cells to some extent. Conclusion DC can be induced from CMBC with the cytokine cocktail and they show a strong antigen-presenting ability. DC produced in this way and pulsed by HBsAg can activate HBsAg-specific CTL in vitro. This might mean that it could be a new way to break the tolerance to HBV in chronic HBV-infected patients.