干扰素α对恶性造血细胞系主要组织相容性复合体Ⅰ类链相关蛋白A表达的上调作用

摘要

Objective To investigate the effect of interferon-α (IFN-α) on expression of major histocompatibility complex (MHC) class I chain-related protein A (MICA) in the malignant hematopoietic cell lines.Methods The myeloid leukemia cell lines K562 and B-cell lymphoma cell line Raji were treated with IFN-α.The expression of MICA was measured by RT-PCR and immunohistochemical staining at mRNA and protein level.The cytotoxicity of human NK cells to the IFN-α treated malignant hematopoietic cells was detected by MTT method.Results After being treated with 1000 U/ml IFN-α,up-regulation of MICA mRNA in Raji and K562 cells were respectively found in 24 h and 48 hours (t =17.016,P ＜0.05; t =5.616,P ＜0.05).After being treated with IFN-α 72 hours,up-regulation of MICA mRNA in K562 and Raji were found at the dose of 500 U/ml and 1000 U/ml dose (t =6.622,P ＜0.05; t =9.071,P ＜0.05).The mRNA and protein expression of MICA were up-regulated by IFN-o in the two malignant hematopoietic cells in a time and dosedependent manner.After being treated with 1000 U/ml IFN-o for 72 hours,the susceptibility of the two malignant hematopoietic cells to NK cytolysis was significantly increased (t =20.016,P ＜0.05; t =7.969,P ＜0.05).Moreover,the up-regulated susceptibility can be blocked by anti-MICA antibody.Conclusion IFN-α can up-regulate the MICA expression in the malignant hematopoietic cell lines and thereby enhance the susceptibility to cytolysis of NK cells.%目的 观察干扰素α(IFN-α)对恶性造血细胞系主要组织相容性复合体(MHC)Ⅰ类链相关蛋白A( MICA)表达的影响.方法 反转录-聚合酶链反应(RT-PCR)法检测人类慢性髓系白血病细胞K562及人类伯基特淋巴瘤细胞Raji细胞MICA mRNA的表达,免疫组织化学法检测MICA蛋白的表达,四甲基偶氮唑蓝(MTT)比色法检测人类外周血自然杀伤(NK)细胞对肿瘤细胞的杀伤.结果 K562细胞MICA表达阳性,Raji细胞MICA表达阴性.Raji和K562细胞分别在1000U/ml IFN-α诱导24 h和48 h时MICA mRNA开始表达上调(t=17.016,P＜ 0.05;t=5.616,P＜ 0.05).72 h Raji细胞和K562细胞分别在500 U/ml和1000 U/ml诱导条件下MICA mRNA表达开始上调(t=6.622,P＜ 0.05;t=9.071,P＜0.05).IFN-α对MICA mRNA表达的上调作用呈一定时间和剂量依赖关系,且蛋白与mRNA表达水平一致.1000 U/ml IFN-α诱导72 h后,Raji细胞和K562细胞对NK细胞杀伤的敏感性明显上调(t=20.016,P＜0.05；t=7.969,P＜0.05),抗MICA抗体封闭MICA后,NK细胞对Raji细胞杀伤率恢复至诱导前水平(t=0.393,P＞ 0.05),而K562细胞则低于诱导前水平(t=9.841,P＜ 0.05).结论 IFN-α上调了恶性造血细胞中MICA基因的转录表达,继而增强了NK细胞对其识别与杀伤.