CD4+CD25+ regulatory T cell-mediated changes in the expression of endocytic receptors and endocytosis process of human dendritic cells.

+ CD25 + regulatory T cells abstract CD4 + CD25 + regulatory T cells (Tregs) are known to inhibit immune responses to antigens. Since, the process of antigen uptake by dendritic cells (DC) is central to induction of immune responses, we ana- lyzed the effect of Tregs on the expression of endocytic receptors on DC and its repercussion on antigen uptake. Our results demonstrate that Tregs down-regulate the expression and uptake of antigens via C-type lectin-like receptors CD206 and DC-SIGN, restrain the pinocytosis process of DC and augment the expression of FcRIIB, an inhibitory Fc receptor the engagement of which by IgG-bound antigens leads to inhibition of DC activation. Our results thus provide an additional insight on the pertinence of strategies aimed at blocking Treg functions towards improved vaccination protocols.