Freshly Isolated Peyer's Patch, but Not Spleen, Dendritic Cells Produce Interleukin 10 and Induce the Differentiation of T Helper Type 2 Cells

Orally administered antigens often generate immune responses that are distinct from those injected systemically. The role of antigen-presenting cells in determining the type of T helper cell response induced at mucosal versus systemic sites is unclear. Here we examine the phenotypic and functional differences between dendritic cells (DCs) freshly isolated from Peyer's patches (PP) and spleen (SP). Surface phenotypic analysis of CD11c+ DC populations revealed that PP DCs expressed higher levels of major histocompatibility complex class II molecules, but similar levels of costimulatory molecules and adhesion molecules compared with SP DCs. Freshly isolated, flow cytometrically sorted 98–100% pure CD11c+ DC populations from PP and SP were compared for their ability to stimulate naive T cells. First, PP DCs were found to be much more potent in stimulating allogeneic T cell proliferation compared with SP DCs. Second, by using naive T cells from ovalbumin peptide–specific T cell receptor transgenic mice, these ex vivo DCs derived from PP, but not from SP, were found to prime for the production of interleukin (IL)-4 and IL-10 (Th2 cytokines). In addition, PP DCs were found to prime T cell