IL-10 and IL-27 producing dendritic cells capable of enhancing IL-10 production of T cells are induced in oral tolerance.

Oral tolerance is a key feature of intestinal immunity, generating systemic tolerance to ingested antigens (Ag). Dendritic cells (DC) have been revealed as important immune regulators, however, the precise role of DC in oral tolerance induction remains unclear. We investigated the characteristics of DC in spleen, mesenteric lymph node (MLN), and Peyer's patch (PP) after oral Ag administration in a TCR-transgenic mouse model. DC from PP and MLN of tolerized mice induced IL-10 production but not Foxp3 expression in cocultured T cells. IL-10 production was markedly increased after 5-7-day Ag administration especially in PP DC. On the other hand, IL-27 production was increased after 2-5-day Ag administration. CD11b(+) DC, which increased after ingestion of Ag, prominently expressed IL-10 and IL-27 compared with CD11b(-) DC. These results suggest that IL-10 and IL-27 producing DC are increased by interaction with antigen specific T cells in PP, and these DC act as an inducer of IL-10 producing T cells in oral tolerance.