Small intestinal CD103 ⁺ dendritic cells display unique functional properties that are conserved between mice and humans

Abstract

A functionally distinct subset of CD103 ⁺ dendritic cells (DCs) has recently been identified in murine mesenteric lymph nodes (MLN) that induces enhanced FoxP3 ⁺ T cell differentiation, retinoic acid receptor signaling, and gut-homing receptor (CCR9 and α4β7) expression in responding T cells. We show that this function is specific to small intestinal lamina propria (SI-LP) and MLN CD103 ⁺ DCs. CD103 ⁺ SI-LP DCs appeared to derive from circulating DC precursors that continually seed the SI-LP. BrdU pulse-chase experiments suggested that most CD103 ⁺ DCs do not derive from a CD103 ⁻ SI-LP DC intermediate. The majority of CD103 ⁺ MLN DCs appear to represent a tissue-derived migratory population that plays a central role in presenting orally derived soluble antigen to CD8 ⁺ and CD4 ⁺ T cells. In contrast, most CD103 ⁻ MLN DCs appear to derive from blood precursors, and these cells could proliferate within the MLN and present systemic soluble antigen. Critically, CD103 ⁺ DCs with similar phenotype and functional properties were present in human MLN, and their selective ability to induce CCR9 was maintained by CD103 ⁺ MLN DCs isolated from SB Crohn's patients. Thus, small intestinal CD103 ⁺ DCs represent a potential novel target for regulating human intestinal inflammatory responses.