THE EFFECTS OF CD59 AND CD55 ON ACTIVATION-SIGNAL TRANSDUCTION OF T CELL

Objective To study the synergistic effects of glycosylphosphatidyl inositol(GPI)-anchored protein CD59 and CD55 in lipid raft-mediated T cell signal transduction. Methods Construction of recombinant vectors pSUPER-siCD55and pSUPER-siCD59 targeting CD55 and CD59 gene with siRNA technique.Human Jurkat cells were divided into three groups: Jurkat cell group(group 1),Jurkat cells transfected with pSUPER-CD59-siRNA plasmid(group 2) and Jurkat cells transfected with pSUPER-CD55-siRNA plasmid(group 3) The expressions of CD59 and CD55 mRNA in transfected cells were detected by RT-PCR.The cell proliferation activity of the three groups was measured by MTT colorimetry after crosslinking anti-CD55 mAb and anti-CD59 mAb,and the changes of calcium ion concentration in the cytoplasm were determined by laser scanning confocal microscope.Results Compared with group 1,expressions of CD59 mRNA in group 2 and CD55 mRNA in group 3 were significantly decreased(F=595.14,699.06;q=45.70-47.25;P0.05).The reproductive activity and calcium ion level in group 1,after crosslinking of CD55 and CD59,were higher than that in both groups 1and 3(F=97.02,189.47;q=13.69-26.39;P0.01),but that in group 2 were lower than group 3(q=5.43,6.42;P0.05). Conclusion CD59 and CD55 have synergistic effects on activation signal transduction of T cell,in which,CD59 being more important.