IL-15上调NKG2D表达对CIK细胞杀伤活性的增强效应

目的观察IL-15对细胞因子诱导的杀伤细胞( Cytokine-induced killer cells，CIK)NKG2D受体表达及其对食管癌EC9706细胞杀伤活性的影响。方法体外分离外周血单个核细胞，分为两组。对照组：干扰素-γ、白细胞介素-2、CD3单抗诱导培养CIK细胞。IL-15组：加用IL-15培养。流式细胞仪检测细胞免疫表型及CD3+细胞、CD56+细胞表面NKG2D的表达，LDH法测定第14天细胞在效靶比20∶1、30∶1时对EC9706细胞的杀伤活性；效靶比30∶1时，观察NKG2D单抗封闭细胞表面NKG2D分子后对两组细胞杀伤活性的影响。结果随着培养时间的延长，CIK群体细胞及CD56+细胞表面NKG2D表达逐渐增强，IL-15组与对照组相比差异有统计学意义(P＜0.05)；效靶比20∶1、30∶1时，IL-15组细胞对EC9706细胞的杀伤活性均较对照组明显增强，差异均有统计学意义(P＜0.05)；效靶比30∶1时NKG2D单抗封闭CIK细胞表面NKG2D分子后，对照组细胞、IL-15组细胞对EC9706细胞的杀伤活性均较阻断前明显下降，差异均有统计学意义 (P＜0.05)。结论IL-15上调CIK细胞表面NKG2D分子表达，增强CIK细胞对EC9706细胞的杀伤活性，CIK细胞通过NKG2D发挥作用。

Enhancement of Cytotoxicity against IL-15 Up-regulate NKG2D Expression on Cytokine-induced Killer Cells

ObjectiveTo analyse the effects of IL-15 on the expression of NKG2D and the cytotoxicity of cytokine-induced killer (CIK) cells against human esophagus carcinoma cell EC9706 in vitro. MethodsPeripheral blood mononuclear cells were isolated from healthy donors then divided into two groups: the control group ( cells were cultured in the presence of IFN-γ, anti-CD3 antibody and IL-2) and IL-15 group (cells were cultured in the presence of IFN-γ, anti-CD3 antibody, IL-2 and 10 ng/ml IL-15). Phenotypic characteristics of CIK cells and the expression of NKG2D were analyzed by flow cytometry. After 14 days culture, cytotoxicity of CIK cells against EC9706 cells was measured by using a standard LDH releasing assay. Effector cells were added to target cells at E∶T radios of 20∶1, 30∶1. In blocking experiments, NKG2D monoclonal antibody was added to CIK cells for 15 min before plating at 30∶1 E∶T ratio. ResultsNKG2D molecules were significantly up-regulated during the culture period on CD3+ cells (the CIK cells population) and the CD56+cells. The differences of NKG2D expressions were significant between IL-15 group and the control group (P＜0.05). Cytotoxicity of CIK cells treated by the IL-15 group was higher than that of the control group, both at 20∶1 E∶T ratios and at 30∶1 E∶T ratios (P＜0.05). When the NKG2D molecules on CIK cell ular membrance were blocked by the NKG2D monoclonal antibody, the cytolytic activity in the control group cells and IL-15 group cells was significantly inhibited. ConclusionIL-15 up-regulated the expression of NKG2D on CIK cells, which enhanced the NKG2D mediated cytotoxicity against EC9706 cells.CIK cells played a role through the NKG2D molecules.