title: Characterization of colonic and mesenteric lymph node dendritic cell subpopulations in a murine adoptive transfer model of inflammatory bowel disease.
abstract: Ulcerative colitis and Crohn's disease, collectively termed inflammatory bowel diseases (IBD), are chronic inflammatory diseases of the intestine that afflict more than 4 million people worldwide. Intestinal inflammation is characterized by an abnormal mucosal immune response to normally harmless antigens in the gut flora. In Crohn's disease, the pathogenic mucosal immune response is a typical T helper (TH1) type cell response, whereas ulcerative colitis is predominantly associated with a TH2 response. We are interested in the role of dendritic cells in early immunologic events leading to T cell activation and chronic intestinal inflammation. Using a murine adoptive transfer model of IBD, we found an accumulation of dendritic cells in colon and mesenteric lymph nodes during the early stage of IBD before the appearance of epithelial lesions and tissue degradation. In situ immunostaining and flow-cytometric analysis revealed that approximately 50% of colonic dendritic cells were CD11b B220 myeloid dendritic cells and 50% expressed the CD11b B220 plasmacytoid phenotype. In corresponding mesenteric lymph nodes, approximately 16% were plasmacytoid dendritic cells. Colonic myeloid dendritic cells were shown to express the co-stimulatory molecule CD40. Both, colonic myeloid and plasmacytoid dendritic cells released interferon-alpha in situ and stimulated T cell proliferation ex vivo. Our results show that dendritic cells can mature in the intestine without migrating to mesenteric lymph nodes. Mature intestinal dendritic cells may form a nucleation site for a local T cell response and play an important role in the pathogenesis of IBD.
authors.affiliation: Child Health Research Institute, Women's and Children's Hospital, North Adelaide, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Karlis
authors.forename: Irmeli
authors.initials: I
authors.lastname: Penttila
authors.forename: Tuyet B
authors.initials: TB
authors.lastname: Tran
authors.forename: Ben
authors.initials: B
authors.lastname: Jones
authors.forename: Silvia
authors.initials: S
authors.lastname: Nobbs
authors.forename: Heddy
authors.initials: H
authors.lastname: Zola
authors.forename: Inge Ea
authors.initials: IE
authors.lastname: Flesch
mesh_terms: D000818:Animals; D003093:Colitis, Ulcerative / Q000473:pathology*; D003106:Colon; D003424:Crohn Disease / Q000473:pathology*; D003713:Dendritic Cells / Q000166:cytology*; D004195:Disease Models, Animal; D005260:Female; D005434:Flow Cytometry; D008198:Lymph Nodes / Q000166:cytology*; D008297:Male; D008643:Mesentery; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID