The calcineurin inhibitor tacrolimus allows the induction of functional CD4+CD25+ regulatory T cells by rabbit anti-thymocyte globulins

Rabbit anti-thymocyte globulins (rATG) induce CD4+CD25 +forkhead box P3 (FoxP3+) regulatory T cells that control alloreactivity. In the present study, we investigated whether rATG convert T cells into functional CD4+CD25+FoxP3+CD127 -/low regulatory T cells in the presence of drugs that may hamper their induction and function, i.e. calcineurin inhibitors. CD25neg T cells were stimulated with rATG or control rabbit immunoglobulin G (rIgG) in the absence and presence of tacrolimus for 24 h. Flow cytometry was performed for CD4, CD25, FoxP3 and CD127 and the function of CD25+ T