Recent studies show the existence of multiple subsets of antigen-presenting cells in the lamina propria (LP), mesenteric lymph node (MLN) and Peyers patches (PP). In the lamina propria CD11b+ intestinal macrophages induce the differentiation of Foxp3+ regulatory T cells via retinoic acid, via a mechanism dependent on both RA and IL-10[52] and these cells can also inhibit the induction of Th-17 responses induced by CD11b+ DCs in the lamina propria [52,56]. In contrast, it has also been shown that lamina propria DCs induce Foxp3+ T regulatory cells [51]. In the MLN, CD103+ DCs that produce RA promote the differentiation of Foxp3+ regulatory T cells [49], as well as IgA-secreting B cells [64]. In contrast, CD103− DCs in the MLN do not promote Foxp3+ T regulatory cells, but can be stimulated to produce greater levels of the pro-inflammatory cytokines TNF-α, IL-6, IL-12p40 and IL-23 [49], raising the possibility that they may induce Th1/Th17 responses. In the PP, CD11c+CD11b−CD8α+ DCs can be induced to secrete high amounts of IL-12p70 promote Th1 responses [43,74,75]; in contrast, CD11c+CD11b+CD8α− DCs secrete high amounts of IL-10 promote Th2 responses [43,74,75]. Solid lines represent published data. Dotted lines represent speculations.