扩增的NK细胞对胃癌细胞的杀伤作用及其机制

目的：探讨扩增的自然杀伤（NK）细胞对胃癌细胞的杀伤作用，阐明其作用机制。方法：提取和分离15例胃癌患者外周血单个核细胞（PBMCs）。观察扩增前后NK细胞形态表现，检测扩增前后NK细胞百分比，计算扩增后NK细胞扩增倍数，检测扩增前后NK细胞对胃癌细胞的杀伤作用，流式细胞术检测NK细胞表面活化性受体NKG2D和DNAM-1以及抑制性受体KIR2DL1和KIR3DL1的表达百分比。结果：扩增前NK细胞呈圆形，细胞体积比较小，细胞呈散在分布，扩增后NK细胞体积明显增大，细胞呈不规则形态。扩增后NK细胞百分比明显高于扩增前（P<0.01），扩增后NK细胞数是扩增前的（596±152）倍。在效靶比为5∶1时，扩增后NK细胞对胃癌细胞的杀伤活性明显强于扩增前（P<0.01）。扩增后NK细胞表面活化性受体NKG2D和DNAM-1表达百分比明显高于扩增前（P<0.01）。扩增后NK细胞表面抑制性受体KIR2DL1和KIR3DL1表达百分比明显低于扩增前（P<0.05）。结论：扩增后NK细胞对胃癌细胞杀伤作用明显强于扩增前，其机制可能与扩增后NK细胞表面活化性受体表达升高和抑制性受体表达降低有关联。

Killing effect of amplified NK cells on gastric cancer cells and its mechanism

Objective: To investigate the killing effect of amplified natural killer (NK) cells on the gastric cancer cells,and to elucidate its mechanism. Methods: The peripheral blood mononuclear cells (PBMCs) from 15 patients with gastric cancer were extracted and isolated. The morphology of NK cells before and after amplification was observed, the percentages of NK cells before and after amplification were detected, and the amplification time of NK cells after amplification was calculated.The killing effects of NK cells on the gastric cancer cells before and after amplification were detected. The percentages of expressions of killing activating receptors NKG2D and DNAM-1 and killing inhibitory receptors KIR2DL1 and KIR3DL1 were detected by flow cytometry. Results: Before amplification, the NK cells were round, small in size and scattered in distribution. After amplification, the NK cells were increased in size and irregular in shape. The percentage of NK cells after amplification was significantly higher than that before amplification (P<0.01), and the number of the NK cells after amplification was (596±152) times of before amplification. When the effective target ratio was 5:1, the killing activity of NK cells on the gastric cancer cells after amplification was significantly higher than that before amplification (P<0.01).After amplification, the percentages of expressions of killing activating receptors NKG2D and DNAM-1 were significantly higher than those before amplification (P<0.01).After amplification, the percentages of expressions of killing inhibitory receptors KIR2DL1 and KIR3DL1 were significantly lower than those before amplification (P<0.05). Conclusion: The killing effect of NK cells on the gastric cancer cells after amplification is stronger than before amplification. The mechanism may be related to increasing the expressions of activated receptors and decreasing the expressions of inhibitory receptors on the surface of NK cells after amplification.