Human CD4+CD25highRegulatory T Cells Inhibit Myeloid but Not Plasmacytoid Dendritic Cells Activation.

CD4+CD25+regulatory T cells (Treg) are essential negative regulators of immune responses. However, the mechanisms of immune suppression and the spectrum of cells they target remain incompletely defined. In particular, although Treg directly suppress conventional T cells in vitro, they might also affect antigen presenting cells (APC).