Cutting edge:: Human CD4+CD25+ T cells restrain the maturation and antigen-presenting function of dendritic cells

The characteristics and functions of CD4(+) CD25(+) regulatory cells have been well defined in murine and human systems. However, the interaction between CD4(+) CD25(+) T cells and dendritic cells (DC) remains unclear. In this study, we examined the effect of human CD4(+) CD25(+) T cells on maturation and function of monocyte-derived DC We show that regulatory T cell render the DC inefficient as APCs despite prestimulation with CD40 ligand. This effect was marginally reverted by neutralizing Abs to TGF-beta. There was an increased IL-10 secretion and reduced expression of costimulatory molecules in DC Thus, in addition to direct suppressor effect on CD4(+) T cell, regulatory T cells may modulate the immune response through DC.