中文摘要：

背景：研究表明部分肾移植受者在移植前就产生了MHC-I类链相关基因A（MICA）抗体,包括部分自身抗体,其急性排斥反应发生率明显高于抗体阴性者.目的：探讨外源性抗原对内皮细胞MICA表达的影响.方法：分别以5,10和25 μg/L 3个剂量,将MICA重组蛋白分为M5,M10,M25组,将热休克蛋白分为H5,H10,H25组,对人脐静脉内皮细胞予以诱导培养48 h,对照组加入等量的磷酸盐缓冲液.结果与结论：用MICA重组蛋白诱导48 h后,各实验组（M5,M10,M25）内皮细胞MICA mRNA和MICA蛋白的表达量与对照组比较均有显著增加（P 〈 0.05）.M5组和M10组MICA mRNA和MICA蛋白均高于M25组 （P 〈 0.05）.MICA膜蛋白表达以M10组最高,并与M5组、M25组之间差异有显著性意义（P 〈 0.05）.各实验组（M5,M10,M25）可溶性MICA水平较对照组显著下降（P 〈 0.05）.热休克蛋白组内皮细胞MICA基因的表达和可溶性MICA水平均无明显改变.结果表明外源性MICA抗原能够诱导内皮细胞自身MICA mRNA和蛋白表达上调,尤其是细胞膜蛋白增加明显,但可溶性MICA水平显著下降.

英文摘要：

BACKGROUND： Studies have demonstrated that incidence rate of acute rejection in renal transplant recipients with pre-production of major histocompatibility complex class I chain-related gene A （MICA）, including parts of autoantibody, before transplantation in body, is obviously greater than that of recipients with negative antibody. OBJECTIVE： To investigate effects of exogenous antigen on MICA expression in endothelial cells. METHODS： The endothelial cells were cultured with exogenous recombinant MICA protein （group M5, M10 and M25） and heat shock protein-70 （group H5, H10 and H25） with dosages of 5, 10 and 25 μg/L, respectively, for 48 hours. Same volume of phosphate buffer saline was added into the control groups. RESULTS AND CONCLUSION： At 48 hours after induction, the expressions of MICA mRNA and protein were increased significantly in each experimental group （M5, M10 and M25） than that of the control group with significant （P 〈 0.05）. The expression of MICA mRNA and MICA protein of group M5 and group M10 were remarkably higher than group M25 （P 〈 0.05）; however, there was no significant difference between group M5 and M10 （P 〉 0.05）. The expression of MICA membrane protein in the group M10 was obviously greater than that of the group M5 and M25 （P 〈 0.05）. The level of soluble MICA （sMICA） in experimental groups （M5, M10 and M25） was decreased obviously comparing with that of the control group. These differences had statistical significances （P 〈 0.05）. But there was no significant difference among the experimental groups （P 〉 0.05）. However, the expression of MICA gene and sMICA level did not change after heat shock protein-70 stimulation. The exogenous MICA antigen up-regulates the expression of MICA mRNA and protein, especially increases the expression of membrane protein on the cell surface significantly, but sMICA in supernatant was dramatically decreased.