Dendritic cells in islets of Langerhans constitutively present beta cell-derived peptides bound to their class II MHC molecules.
Islets of Langerhans from normal mice contained dendritic cells (DCs) in the range of 8-10 per islet. DCs were found in several mouse strains, including those from lymphocyte-deficient mice. DCs were absent in islets from colony stimulating factor-1 deficient mice and this absence correlated with small size islets. Most DCs were found next to blood vessels and resided in islets for several days. Some DCs contained insulin-like granules, and most expressed peptide-MHC complexes derived from beta cell proteins. Islet DCs were highly effective in presenting beta cell antigens to CD4 T cells ex vivo. Presentation of beta cell-derived peptide-MHC complexes by DCs neither depended on islet inflammation nor correlated with the extent of spontaneous beta cell death. Periislet stroma DCs did not contain beta cell peptide-MHC complexes; however, 50% of DCs in pancreatic node were positive. Hence, presentation of high levels of beta cell antigens normally takes place by islet DCs, a finding that has to be placed in the perspective of autoimmune diabetes.
Calderon
Boris
B
Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Suri
Anish
A
Miller
Mark J
MJ
Unanue
Emil R
ER
D000818:Animals; D017951:Antigen Presentation; D015703:Antigens, CD / Q000032:analysis; D001681:Biological Assay; D002452:Cell Count; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007249:Inflammation / Q000276:immunology; D007328:Insulin / Q000276:immunology*; D050417:Insulin-Secreting Cells / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D010455:Peptides / Q000032:analysis / Q000276:immunology
D015703:Antigens, CD; D000949:Histocompatibility Antigens Class II; D007328:Insulin; D010455:Peptides