CD4^+CD25^+CD127^-T细胞在抗CD45RB抗体诱导免疫耐受中的作用

The induction of CD4^+CD25^+CD127^-T cells in an immune tolerance model triggered by engagement of anti-CD45RB mAb

目的:研究CD4+CD25+CD127-T细胞在抗CD45RB抗体诱导的免疫耐受中所发挥的作用,从而阐明抗CD45RB抗体诱导免疫耐受作用的机制。方法:体内实验建立小鼠异位心脏移植模型,观察抗CD45RB抗体对移植物生存期的影响。体外实验观察抗CD45RB抗体对T细胞增殖抑制能力和对CD4+CD25+CD127-T细胞生成的影响。流式细胞术检测外周血和混合细胞中CD4+CD25+CD127-T细胞百分率,ELISA法检测血清和培养液中IL-2和IL-10含量,Real-TimePCR法检测脾脏和混合细胞中Foxp3基因的表达,移植心脏病理学观察。结果:抗CD45RB抗体显著延长移植物存活时间(P<0.01),对ConA刺激引起的T淋巴细胞增殖具有明显的抑制能力(P<0.05)。与对照组相比,实验组CD4+CD25+CD127-T细胞百分率和Foxp3 mRNA表达量均明显增加(P<0.05),实验组IL-2水平较对照组明显降低(P<0.05),但IL-10含量较对照组明显升高(P<0.05)。病理结果显示对照组移植心脏出现典型细胞免疫性损伤病理改变,而实验组中几乎无炎性细胞浸润现象。结论:抗CD45RB抗体能显著延长移植物存活时间,其诱导免疫耐受机制与上调CD4+CD25+CD127-T细胞百分率和增加Foxp3 mRNA表达量有关。

Objective：To investigate the relationship between CD4＋CD25＋CD127-T cells and anti-CD45RB mAb induced immune tolerance.Methods：The cardiac heterotopic allografting model in mice was established by the ventral transplantation of cardiac allograft.Immunotolerance was induced by use of anti-CD45RB mAb.The mice were divided into two groups designated as the rejected group and treated group,respectively.Mean survival time of transplants in the two groups was observed and in vitro proliferation of recipients T cells was measured.The effect of CD4＋CD25＋CD127-T cells treated with anti-CD45RB mAb was observed in vitro.The ratio of CD4＋CD25＋CD127-T cells treated with anti-CD45RB mAb in vitro and vivo were measured by FCM.The levels of IL-2 and IL-10 were tested by ELISA.The expression of Foxp3 mRNA was detected by Real-Time PCR.Allografts were evaluated by pathologic histological.Results：A single injection of anti-CD45RB mAb could prolong the survival of allografs.The proliferation of T lymphocytes induced by ConA was inhibited evidently by anti-CD45RB mAb.The ratio of CD4＋CD25＋CD127-T cells and the expression of Foxp3 mRNA in the mice were increased when compared with control either in vitro or in vivo.The level of IL-2 decreased in the mice,but the amount of IL-10 changed oppositely.In the rejected group,the number of infiltrating cells was much more than in treated group,and also,the extent of pathological histology was more severe.Conclusion：Anti-CD45RB mAb could prolong the survival of allografs.The mechanism of tolerance induced may be associated with up-regulating the ratio of CD4＋CD25＋CD127-T cells and the enhanced expression of Foxp3 mRNA.