Dendritic Cells in the Gastrointestinal System: Division of Labor, Plasticity, and Niche-Specific Adaptation.

The intestinal immune system is constantly challenged to distinguish between innocuous dietary antigens, commensal microbiota and intestinal self-antigens (self-Ags) versus harmful pathogens and malignant cells. It resides in the intestinal wall itself, Peyer's patches (PPs) and the draining lymph nodes (LNs). Dendritic cells (DCs) are found in all of these structures and are professional antigen-presenting cells (APCs) dictating and maintaining T cell fate. Here, we review how DCs contribute to immune homeostasis in the gastrointestinal system through multiple strategies: division in labor and strategic anatomical positioning between DC subtypes, plasticity and site-specific functional adaptation. While these properties of DCs are likely not unique to the gastrointestinal tract, it is the site where we have learned most about how this DC network operates.