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

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.