Aim: To isolate CD4(+) CD25(+) Treg cells from human peripheral blood, and study their functional characteristics.
Methods: The expressions of Foxp3 in human CD4(+) CD25(+) Treg cells were test by RT-PCR. The regulatory properties of CD4(+) CD25(+) Treg cells were assessed by co-culturing with CD4(+) CD25(-) T cells and CD8(+) T cells, or adding exogenous IL-2. The detection of intracellular cytokine production of IL-4, IL-10 and IFN-gamma was done by flow cytometry.
Results: CD4(+) CD25(+) Treg cells highly expressed Foxp3 and mainly synthesized IL-10 that suppressed the proliferation of CD4(+) CD25(-) T and CD8(+) T cells. Its suppressive function was reversed by high concentration of IL-2 and (or) IL-4.
Conclusion: CD4(+) CD25(+) Treg cells exhibited a subpopulation of immunoregulatory T cells with suppressive function, which could be reversed by high concentration of IL-2.