IL-12与IL-18在体外培养系统中诱导肿瘤特异性CTL杀伤活性的比较

目的：分别应用重组人白细胞介素12（rhIL-12）及重组人白细胞介素18（rhIL-18）在体外培养系统(CCs)中诱导肿瘤特异性细胞毒性T淋巴细胞(CTL),比较IL-18与IL-12诱导的肿瘤特异性CTL的杀伤活性，探索IL-18的抗肿瘤作用机制。方法：采用Stem Sep^TM免疫磁性细胞分离法分离人外周血NK细胞、T细胞及DCs细胞，流式细胞仪分析细胞表型，¹²⁵I-UdR标记的细胞毒实验检测杀伤活性。结果：在CCs中、在肿瘤抗原存在的条件下，rhIL-18和rhIL-12均能诱导产生针对U251、MCF7特异性CTL，其作用能力与rhIL-18和rhIL-12的浓度呈剂量依赖关系，但rhIL-18诱导肿瘤特异性CTL的作用明显高于rhIL-12（P<0.01）；rhIL-18和rhIL-12在诱导肿瘤特异性CTL过程中具有协同作用，两者联合应用诱导肿瘤特异性CTL的能力明显高于单独应用rhIL-18和rhIL-12（P<0.01）。结论：rhIL-18和rhIL-12在CCs中均能够诱导并促进CTL介导的肿瘤特异性杀伤效应，rhIL-18诱导的肿瘤特异性CTL的能力明显高于rhIL-12，两者在诱导肿瘤特异性CTL过程中具有协同作用。

Comparison of cytotoxicity of tumor specific CTL induced by IL-18 and IL-12 in cell co-culture system in vitro

Objective To compare the efficiency of IL-18 and IL-12 in inducing the tumor specific CTL in vitro,and test the cytotoxicities of tumor specific CTL induced in the same culture system with IL-18 or IL-12.Methods The NK cells,T cells and dendritic cells were separated from fresh PBMNCs by using the Stem SepTM immunomagnetic beads.Cell phenotypes of the purified cell populations were identified with FCM technique.The cell co-culture system was established as follows:the cell preparations in which definite cell subset had been deleted was co-cultivated with mitotic-inactivated tumor cells in the presence of rhIL18 and/or rhIL-12.Cytotoxicities of the various effector cell preparations to a series of tumor cell lines were examined by the isotope releasing assay.Results In the cell co-culture system in vitro,rhIL-18 or rhIL-12 alone and dose-dependently induced tumor specific cytotoxicities.The level of cytolytic activity of the tumor specific CTL induced by IL-12 was substantially inferior to that induced by IL-18(P<0.01).Conclusion These results suggest that IL-12 does not induce tumor-specific CTL as efficiently as IL-18 does in this co-culture system under these conditions,but the synergistic effect could be observed during administration of IL-18 and rIL-12.