IL-2促进PBMC来源的NK、NKT、CD8+T细胞高表达NKG2D

目的 观察大剂量IL-2活化的人外周血单个核细胞（PBMC）中，NKG2D在NK细胞、T细胞和NKT细胞表面的表达规律。方法 使用三重免疫荧光标记的流式细胞术检测NKG2D的表达情况。使用sMICA蛋白与人PBMC共同培养，之后使用流式细胞术分析NKG2D在NK细胞中的表达情况。使用半定量RT-PCR方法检测大剂量IL-2活化的人PBMC中NKG2D及其锚定蛋白DAP10 mRNA的表达变化。结果 使用大剂量IL-2活化人PBMC细胞后，NKG2D在NK细胞、CD^＋T细胞和NKT细胞表面的表达均增加，但是在CD4^＋T细胞表面始终不表达。同时IL-2可以拮抗sMICA对NKG2D的下调作用。半定量RT-PCR结果显示，使用大剂量IL-2活化人PBMC之后，NKG2D及其锚定蛋白DAP10的mRNA水平并不发生明显变化。结论 大剂量IL-2培养人PBMC之后，NKG2D在NK细胞、CD8^＋T细胞和NKT细胞表面的表达均增加，可能是PBMC活化并获得广谱抗肿瘤效应的机制之一．

Expression pattern of NKG2D on different subsets of high doses IL-2 activated human

Objective To investigate the expression pattern of NKG2D on different subsets of high doses IL-2 activated human PBMC. Methods Expression of NKG2D on high doses IL-2 activated human PBMC was detected using triple fluorescent staining and flow cytometry analysis. Expression of NKG2D was also detected after PBMC were treated with sMICA and with or without IL-2 respectively. To further investigate the function of NKG2D in killing of tumor cells by PBMC treated with IL-2, levels of mRNA of NKG2D and its adaptor protein DAP10 were detected using semi-quantitive RT-PCR. Results The expression of NKG2D was up-regulated on NK cells, CD8+ T cells and NKT cells, but not on CD4+ T cells of human PBMC treated with high doses IL-2. After being treated with sMICA protein, the expression of NKG2D on human PBMC was down-regulated. Alternatively, when treated with IL-2, the effect of sMICA on NKG2D expression could be eliminated. Although the expression of NKG2D on different subsets of PBMC could be up-regulated after being treated with IL-2, similar levels of mRNA of NKG2D and its adaptor protein DAPIO was detected in PBMC treated with or without IL-2. Conclusion The expression of NKG2D was up-regulated on NK cells, CD8+ T cells and NKT cells of high doses IL-2 activated human PBMC, which could explain the high cytotoxity of such cells in the process of cancer treatment. Meanwhile, the up-regulation effect of IL-2 on NKG2D expression could counteract the effect of sMICA which could down-regulate the NKG2D expression in cancer patients and in experiment in vitro to escape the immunosurveillance.