title: Presentation of exogenous antigens on major histocompatibility complex (MHC) class I and MHC class II molecules is differentially regulated during dendritic cell maturation.
abstract: During maturation, dendritic cells (DCs) regulate their capacity to process and present major histocompatibility complex (MHC) II-restricted antigens. Here we show that presentation of exogenous antigens by MHC I is also subject to developmental control, but in a fashion strikingly distinct from MHC II. Immature mouse bone marrow-derived DCs internalize soluble ovalbumin and sequester the antigen intracellularly until they receive an appropriate signal that induces cross presentation. At that time, peptides are generated in a proteasome-dependent fashion and used to form peptide-MHC I complexes that appear at the plasma membrane. Unlike MHC II, these events do not involve a marked redistribution of preexisting MHC I molecules from intracellular compartments to the DC surface. Moreover, out of nine stimuli well known to induce the phenotypic maturation of DCs and to promote MHC II presentation, only two (CD40 ligation, disruption of cell-cell contacts) activated cross presentation on MHC I. In contrast, formation of peptide-MHC I complexes from endogenous cytosolic antigens occurs even in unstimulated, immature DCs. Thus, the MHC I and MHC II pathways of antigen presentation are differentially regulated during DC maturation.
authors.affiliation: Department of Cell Biology and Section of Immunobiology, Ludwig Institute for Cancer Research, Yale University School of Medicine, New Haven, CT 06520-8002, USA.
authors.forename: Lelia
authors.initials: L
authors.lastname: Delamarre
authors.forename: Hilda
authors.initials: H
authors.lastname: Holcombe
authors.forename: Ira
authors.initials: I
authors.lastname: Mellman
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D039521:CD11c Antigen / Q000032:analysis; D019013:CD40 Antigens / Q000378:metabolism; D023201:CD40 Ligand / Q000378:metabolism; D003713:Dendritic Cells / Q000502:physiology*; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000276:immunology; D001613:beta 2-Microglobulin / Q000378:metabolism
chemical_list: D039521:CD11c Antigen; D019013:CD40 Antigens; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D001613:beta 2-Microglobulin; D023201:CD40 Ligand; D010047:Ovalbumin