Impact of exogenous IL-2 the CD4~+CD25~+ regulatory T cells of mice

Objective: To examine the effection of IL-2 on the proliferation and function of CD4+CD25+ regulatory T cells.Methods: The CD4+CD25+ T cells were isolated from B6 mice spleens using FACS.The freshly isolated CD4+CD25+ T cells were cultured with anti-CD3 monoclonal antibody(mAb),syngeneic antigen presenting cells(APCs) and IL-2.Poliferative responses were measured by thymidine incorporation.The suppressive capability and the Foxp3 expression of in vitro-expanded CD4+CD25+ T cells was also investigated.Results: Exogenous IL-2 restored responsiveness of CD4+CD25+ T cells to anti-CD3 antibody.In vitro-expanded CD4+CD25+ T cells suppressed the proliferation of CD25-CD4+ T cells similar to freshly isolated CD4+CD25+ T cells.The Foxp3 expression of in vitro-expanded CD4+CD25+ T cells was also similar to freshly isolated CD4+CD25+ T cells.Conclusion: Exogenous IL-2 could restore the proliferation of anergic CD4+CD25+ regulatory T cells.Furthermore,in vitro-expanded CD4+CD25+ regulatory T cells retain their potent suppressive activity.