抗体阻断表面黏附分子DNAM-1和LFA-1对人自然杀伤细胞肿瘤杀伤活性的抑制作用

Antibody Blockade of Surface Adhesion Molecules DNAM-1 and LFA-1 Inhibits Killing Activity of Natural Killer Cells to Tumor Cells

目的探讨抗体阻断表面黏附分子DNAM-1和LFA-1对体外扩增的人自然杀伤(Natural killer,NK)细胞的肿瘤杀伤活性的影响。方法体外活化人外周血单个核细胞来源的NK细胞,并检测其表面黏附分子DNAM-1和LFA-1的表达水平;通过Trans-well阻隔试验,阻断NK细胞与靶细胞接触,考察细胞-细胞直接接触对NK细胞杀伤活性的影响;通过NK细胞毒性试验,引入抗DNAM-1单克隆抗体和抗LFA-1单克隆抗体,阻断相应信号途径,考察相关黏附分子在NK细胞肿瘤杀伤过程中的作用。结果体外活化的NK细胞高表达表面黏附分子DNAM-1和LFA-1。阻断NK细胞与靶细胞接触,NK细胞的肿瘤杀伤效应大大降低。应用单克隆抗体阻断DNAM-1或LFA-1信号途径,可显著降低NK细胞肿瘤的杀伤效应;联合阻断DNAM-1和LFA-1信号途径,可进一步降低NK的细胞杀伤效应。结论细胞-细胞间直接接触是NK细胞发挥肿瘤杀伤效应的重要机制,表面黏附分子DNAM-1和LFA-1介导的信号途径对维持NK细胞肿瘤杀伤活性具有重要意义。

Objective To investigate the effect of antibody blockage of surface adhesion molecules DNAM-1 and LFA-I on the killing activity to tumor cells of natural killer （NK） cells amplified in vitro. Methods PBMCs-derived NK cells were activated in vitro and determined for the expression levels of surface adhesion molecules DNAM-1 and LFA-1, of which the contact to target cells were blocked by Trans-well test, and the effect of direct cell-cell contact on killing activity of NK cells was investigated. The role of relevant adhesion molecules in killing of tumor cells by NK cells was evaluated by NK cell cytotoxicity test in which the McAbs against DNAM-1 and LFA-1 were introduced to block the corresponding signal pathway. Results DNAM-1 and LFA-1 were highly expressed in the NK cells activated in vitro. The blockage of contact to target cells remarkably decreased, and the blockage of signal pathway of DNAM-1 or LFA-1 significantly decreased, while the combined blockage of signal pathways of DNAM-1 and LFA-1 further decreased the killing activity of NK cells to tumor cells. Conclusion Direct cell-cell contact is an important mechanism of killing activity of NK cells to tumor cells. The signal pathway mediated by surface adhesion molecules DNAM-1 and LFA-1 plays an important role in maintaining the killing activity of NK cells to tumor cells.