IMMUNOBIOLOGY Differentiation of type 1 T regulatory cells (Tr1) by tolerogenic DC-10 requires the IL-10–dependent ILT4/HLA-G pathway

Type 1 T regulatory (Tr1) cells suppress immune responses in vivo and in vitro and play a key role in maintaining toler-ance to self- and non–self-antigens. Interleukin-10 (IL-10) is the crucial driving factor for Tr1 cell differentiation, but the molecular mechanisms underlying this induction remain unknown. We identified and characterized a subset of IL-10– producing human dendritic cells (DCs), termed DC-10, which are present in vivo and can be induced in vitro in the pres