Chemokine (C-C Motif) Receptor 2 Mediates Dendritic Cell Recruitment to the Human Colon but Is Not Responsible for Differences Observed in Dendritic Cell Subsets, Phenotype, and Function Between the Proximal and Distal Colon.

Background & Aims: Most knowledge about gastrointestinal (GI)-tract dendritic cells (DC) relies on murine studies where CD103 DC specialize in generating immune tolerance with the functionality of CD11b subsets being unclear. Information about human GI-DC is scarce, especially regarding regional specifications. Here, we characterized human DC properties throughout the human colon.

Compartment-specific immunity in the human gut: properties and functions of dendritic cells in the colon versus the ileum.

Objective: Dendritic cells (DC) mediate intestinal immune tolerance. Despite striking differences between the colon and the ileum both in function and bacterial load, few studies distinguish between properties of immune cells in these compartments. Furthermore, information of gut DC in humans is scarce.

Human gut dendritic cells drive aberrant gut-specific t-cell responses in ulcerative colitis, characterized by increased IL-4 production and loss of IL-22 and IFNγ.

: The pathogenesis of inflammatory bowel disease is incompletely understood but results from a dysregulated intestinal immune response to the luminal microbiota. CD4 T cells mediate tissue injury in the inflammatory bowel disease-associated immune response. Dendritic cells (DC) generate primary T-cell responses and mediate intestinal immune tolerance to prevent overt inflammation in response to the gut microbiota.

Dysregulated circulating dendritic cell function in ulcerative colitis is partially restored by probiotic strain Lactobacillus casei Shirota.

Background: Dendritic cells regulate immune responses to microbial products and play a key role in ulcerative colitis (UC) pathology. We determined the immunomodulatory effects of probiotic strain Lactobacillus casei Shirota (LcS) on human DC from healthy controls and active UC patients.

Methods: Human blood DC from healthy controls (control-DC) and UC patients (UC-DC) were conditioned with heat-killed LcS and used to stimulate allogeneic T cells in a 5-day mixed leucocyte reaction.