NKG2D在NK细胞杀伤血液肿瘤细胞中的作用

本研究旨在探讨NKG2D在NK细胞杀伤血液肿瘤细胞时是否发挥作用。将多种血液肿瘤细胞株作为靶细胞,并在靶细胞中检测NKG2D相应配体的表达,而后进行杀伤实验。将靶细胞与羧基荧光素二醋酸盐琥珀酰亚胺酯(CFSE)共孵育,同时将NK细胞系NK92MI分别与NKG2D特异性封闭抗体或同型对照抗体共孵育。之后将NK92MI分别与多种血液肿瘤细胞共同培养,2 h后用流式细胞分析方法检测靶细胞的凋亡率。结果显示:加入NKG2D特异性封闭抗体后,NK细胞对于急性髓系白血病细胞Kasumi-1的杀伤作用减弱约30%,而在其他血液肿瘤细胞株中封闭NKG2D并未明显影响NK细胞对于靶细胞的杀伤。结论:在NK细胞作用于某些靶细胞时,NKG2D促进NK细胞的杀伤作用。

Effect of NKG2D in eliminating hematological malignant cell lines by natural killer cells

The aim of this study was to clarify whether NKG2D plays an activating role in eliminating hematological malignant cells lines by natural killer (NK) cells. Several hematological malignant cell lines (K562, NB4, Kasumi-1 THP-1, MV-4-11, MOLT-4, Jurkat, RS4; 11, Raji) were used as target cells. The expression levels of major histocompatibility complex class I (MHC I)-related molecules A/B (MICA, MICB), whose corresponding ligand was NKG2D, were detected in target cells by flow cytometry. Firstly, the target cell lines were co-incubated with carboxyfluorescein succinimidyl ester (CFSE) for 30 min. In the meanwhile, NK92MI, a kind of NK cell line, was co-incubated respectively with isotype control antibody or blocking antibody, the latter could block NKG2D specifically. Then, NK92MI cells were co-cultured with different target cell lines. After incubation for 2 h, the apoptotic ratio of each target cell line was detected by flow cytometry. The results demonstrated that there was a significant reduction of the apoptotic ratio in Kasumi-1, an acute myeloid leukemia cell line, when NK92MI cells were incubated with NKG2D blocking antibody previously. In contrast, the apoptotic ratio of other cell lines varied minimally. It is concluded that NKG2D can activate NK cells through inducing cytotoxicity to certain target cells.