Killing effect of amplified NK cells on gastric cancer cells and its mechanism / 吉林大学学报(医学版)

ABSTRACT

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.