Objective: In mice, a subpopulation of gut dendritic cells (DCs) expressing CD103 drives the development of regulatory T (Treg) cells. Further, it was recently described that the cross-talk between human intestinal epithelial cells (IECs) and DCs helps in maintaining gut immune homeostasis via the induction of non-inflammatory DCs. In this study, an analysis was carried out to determine whether IECs could promote the differentiation of CD103+ tolerogenic DCs, and the function of primary CD103+ DCs isolated from human mesenteric lymph nodes (MLNs) was evaluated.
Methods: Monocyte-derived DCs (MoDCs) and circulating CD1c+ DCs were conditioned or not with supernatants from Caco-2 cells or IECs isolated from healthy donors or donors with Crohn’s disease and analysed for their ability to induce Treg cell differentiation. In some cases, transforming growth factor β (TGFβ), retinoic acid (RA) or thymic stromal lymphopoietin (TSLP) were neutralised before conditioning. CD103+ and CD103− DCs were sorted by fluorescence-activated cell sorting (FACS) from MLNs and used in Treg cell differentiation experiments.
Results: It was found that human IECs promoted the differentiation of tolerogenic DCs able to drive the development of adaptive Foxp3+ Treg cells. This control was lost in patients with Crohn’s disease and paralleled a reduced expression of tolerogenic factors by primary IECs. MoDCs differentiated with RA or IEC supernatant upregulated the expression of CD103. Consistently, human primary CD103+ DCs isolated from MLNs were endowed with the ability to drive Treg cell differentiation. This subset of DCs expressed CCR7 and probably represents a lamina propria-derived migratory population.
Conclusions: A population of tolerogenic CD103+ DCs was identified in the human gut that probably differentiate in response to IEC-derived factors and drive Treg cell development.
Statistics from Altmetric.com
Funding This study was supported by the Crohn’s and Colitis Foundation of America (CCFA to MR); Italian Association for Cancer Research (AIRC to MR); European Research Council (ERC to MR); and the EC 7th Framework Program (IBDase, METAhit to MR).
Competing interests None.
Provenance and Peer review Not commissioned; externally peer reviewed.
Ethics approval The local ethics committee approved the informed consent specifying that material not needed for diagnostic purposes could be used for research purposes.
▸ A more detailed description of the methods and additional figures are published online only at http://gut.bmj.com/content/vol58/issue11
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.