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.