表达HLA-G1的K562细胞抵抗外周血NK细胞杀伤作用的研究

Expression of HLA-G1 antigen on K562 cell inhibits cytotoxicity mediated by NK from PBMC

目的研究 HL A- G1分子对 NK细胞杀伤活性的影响。方法借助脂质体介导的 DNA转染技术 ,将本室构建的真核表达质粒 pc DNA3 - HL A- G1转染人 K5 62细胞 ;通过 G4 18筛选 ,获得克隆化细胞株 K5 62 - G1;应用 RT- PCR及流式细胞术分别在 RNA水平和蛋白质水平检测 HL A- G1的表达 ;最后 ,应用 MTT比色法检测转染细胞对不同个体外周血 NK细胞杀伤活性的抑制效应。结果与转染了空质粒的对照组相比 ,外周血 NK细胞对 K5 62 - G1的杀伤率降低 3 2 .4 3 % ( P <0 .0 1)。结论靶细胞表达 HL A - G1分子可明显抑制 NK细胞的杀伤效应。

ObjectiveTo study whether HLA-G1 molecule itself can inhibit peripheral blood NK cytotoxicity. MethodsThe recombinant expression vector pcDNA3-HLA-G1 was transfected into the human K562 cell line, which is both HLA-Ⅰ negative and reference target for NK lysis. Then the cell line was cloned after corresponding expression product had been demonstrated with the indirect immunofluorescence technique. As shown by RT-PCR and FCM analysis, the HLA-G1 cDNA was successfully integrated into the genome DNA of K562 cell line with effective expression of respective corresponding protein. NK cytotoxicity was observed in peripheral blood mononuclear cells with MTT method. ResultsThe NK cytotoxicity was inhibited in K562-G1(P<0.01)and this inhibition was specific for HLA-G1 because protection was totally reversed by blocking HLA-G1 molecules with a specific monoclonal antibody(mAb)87G. ConclusionHLA-G1 molecule can directly protect target cells from peripheral blood NK cytotoxicity