The Effect In Immuno-characteristic Of Allogeneic Specific Treg In Different Antigen Recognitions

Objectives CD4+CD25+regulatory T cells is an important CD4+regulatory T cells subgroup.This kind of cell subgroup possesses the characteristic of immunosupression and immunopotency.It's mechanism of action maybe through direct contact between cells and (or) secreting suppressor cell factors.It's important in maintaining immune homeostasis,preventing autoimmune disease,guiding transplantation tolerance.But lots of studies concentrated on the effects of different cytokine and ignored the different antigen recognitions.So, to compare different immune-characteristic of Tregs by direct antigen recognition and indirect antigen recognition. To explore whether the indirect way plays the key role in inducing Tregs in immune-tolerance.Methods Recipient peripheral blood mononuclear cells (PBMCs) were isolated by density gradient centrifugation with Ficoll Hypaque. One part were cultured with rhGM-CSF 75ng/ml, rhIL-4 25ng/ml for 4 days to induce human dendritic cells(DCs), and then loading donor antigen cultured for another 3 days. The CD4+CD25- T cells were purified from another part of recipient PBMCs by autoMACS using the human CD4+CD25+ regulatory T cell isolation kits. Two kinds of cells were culture with IL-2 and rapamycin for 5 days to induce antigen-specific CD4+CD25+ regulatory T cells(Treg1) by indirect antigen recognition. At the same time donor PBMCs as antigen presenting cells(APCs) were cultured with recipient CD4+CD25- T cells to induce antigen-specific CD4+CD25+ regulatory T cells(Treg2) by direct antigen recognition. Then comparing two kinds of Tregs in immune-characteristic by lymphocyte proliferation inhibition reaction and production of cytokine IL-2 in the inducement.Results1. Treg1 have a production rate at 62.4% and a proliferation inhibiting rate of 63.5%, while Treg2 have a production rate at 44.4% and a proliferation inhibiting rate of 45.8%2. And also better in the production of cytokine IL-2 in the inducement. Conclusions1. Compared with direct antigen recognition,Tregs induced by indirect antigen recognition have a better comeout no matter in numbers nor immuno-characteristic.2. There is much modest IL-2 produced during the inducement in the indirect recognition.