为了解B7共刺激对细胞因子 ,特别是对IL 2mRNA及转录因子NF κB和AP 1的影响 ,探讨B7介导的IL 2调节的分子机制 ,在异基因混合淋巴细胞反应 (MLR)体系中分别或联合加入抗B7 1、抗B7 2单克隆抗体和CTLA 4Ig以阻断B7/CD2 8信号传导 ,通过竞争性PCR定量检测其对IL 2和IL 4mRNA的影响 ,并初步测定IFN γmRNA的改变 ,同时用转染MHCⅡ类分子及联合转染等量B7 1或B7 2的NIH3T3转基因细胞tDR7,tDR7/B7 1和tDR7/B7 2刺激CD2 8+ T细胞 ,通过DNA 蛋白结合实验观察B7对IL 2转录因子NF κB和AP 1的影响。结果表明 :抗B7 2单抗和CTLA 4Ig可明显抑制B7介导的IL 2和IL 4mRNA合成 ,而抗B7 1单抗仅有轻度抑制作用 ,2种或 3种抗体联合应用时抑制作用相加。MLR 1 - 6小时 ,单独tDR7即可诱导NF κB的表达 ,联合转染B7早期对其结合活力无明显影响 ,6小时后tDR7诱导作用减弱 ,B7却可显著延长tDR7的诱导作用至 72小时。tDR7早期同样可诱导AP 1的表达 ,联合转染B7分子在 2 4小时内对其有一定的抑制作用 ,而在反应后期可延长tDR7对AP 1的上调作用 ,B7 1与B7 2间作用未见明显不同。结论 :B7通过减少IL 2mRNA降解和影响基因转录而上调IL 2分泌 ,并可同时影响多种细胞因子分泌 ;在转录水平B7 1与B7 2作用未见明显不同 ,提示两者的功能 To investigate the effect of B7 costimulation on cytokines, especially IL 2 mRNA and transcription factors NF κB and AP 1, to explore the molecular mechanism of B7-mediated IL 2 regulation in the allogeneic mixed lymphocyte reaction (MLR) system Or combined with anti-B7 1, anti-B7 2 monoclonal antibody and CTLA 4Ig to block B7 / CD28 signaling. The effect of IL-2 and IL-4 mRNA was quantitatively detected by competitive PCR. At the same time, CD8 + T cells were stimulated by tDR7, tDR7 / B7 1 and tDR7 / B7 2 transfected with MHC class Ⅱ molecules and NIH3T3 cells transfected with the same amount of B7 1 or B7 2. The binding of B7 to IL 2 Effects of transcription factor NF κB and AP 1. The results showed that anti-B7 2 monoclonal antibody and CTLA 4Ig could significantly inhibit B7-mediated IL 2 and IL 4 mRNA synthesis, while anti-B7 1 mAb only mild inhibitory effect, two or three antibodies combined with the application of inhibition plus. MLR for 1 to 6 hours, the expression of NF-κB was induced by tDR7 alone. There was no significant effect on the binding activity of B7 in the early transfection of B7 cells. After 6 hours, the induction of tDR7 was weakened, while B7 significantly prolonged the induction of tDR7 to 72 hours. In the early stage of tDR7, the expression of AP 1 was also induced. Combined transfection of B7 molecules inhibited them within 24 hours, but increased the up-regulation of AP 1 by tDR7 in the late stage of the reaction, while the interaction between B7 1 and B7 2 See obviously different. CONCLUSION: B7 can up-regulate the secretion of IL-2 by decreasing the degradation of IL-2 mRNA and influencing the gene transcription, which can affect the secretion of many cytokines at the same time. B7 1 and B7 2 have no obvious difference at the transcriptional level, suggesting that both functions