GPI-PLD基因表达在K562细胞对补体杀伤的敏感性中的影响

目的:观察葡萄糖、胰岛素诱导K562细胞GPI-PLD基因表达对GPI锚定CD55，CD59 的影响，以及对补体依赖的细胞毒(complement dependent cytotoxicity,CDC)杀伤K562细胞的影响。方法:采用免疫印迹检测CD55和CD59表达，定量测定GPI-PLD酶活性，台盼蓝排斥法观察CDC杀伤率。结果:诱导24 h及48 h，胰岛素组、葡萄糖＋胰岛素组酶活性、杀伤率明显增高。24 h时对照组、葡萄糖组、胰岛素组膜蛋白检出CD55，对照组、葡萄糖组膜蛋白及胰岛素组、葡萄糖＋胰岛素组培养基中检出CD59。48 h时对照组膜蛋白，葡萄糖组、胰岛素组、葡萄糖＋胰岛素组培养基检出CD55，CD59。 结论:胰岛素诱导使K562细胞的GPI-PLD酶活性明显升高，导致GPI锚定CD55和CD59释放进入培养基，K562细胞对补体杀伤的敏感性增强。

Effect of the expression of glycosylphosphatidylinositol-specific phospholipase D gene on K562 cell sensitivity to complement killing

Objective To detect the release of glycosylphosphatidylinositol (GPI) anchored CD55 and CD59, and the effect of complement dependent cytotoxicity on K562 cell with expression of GPI-PLD by glucose or insulin. Methods CD55 and CD59 were detected by Western blotting; GPI-PLD activities were analyzed quantitatively; and complement dependent cytotoxicity (CDC) effects were observed by staining of trypan blue. Results After being induced by insulin or glucose for 24 h and 48 h, GPI-PLD activities and rate of CDC killing in the insulin, insulin+glucose groups significantly increased. At 24 h after the inducement, CD55 was found in the membrane proteins in the control, glucose and insulin groups and CD59 in membrane proteins in the control, glucose group, and medium supernatants of insulin, glucose+insulin groups. Both CD55 and CD59 were found in membrane proteins in control group, and medium supernatants of glucose, insulin, glucose+insulin group at 48 h after the inducement.Conclusion Treatment with insulin resulted in the obvious increase of GPI-PLD activity in K562 cell, which led to releasing of GPI anchored CD55 and CD59 into medium,and increased sensitivity of these cells to CDC killing.