title: CD83 localization in a recycling compartment of immature human monocyte-derived dendritic cells.
abstract: Dendritic cells (DC) change their phenotype and functional properties during maturation. CD83 cell surface expression is induced on mature DC (mDC). In this study, we investigated intracellular CD83 localization and transport in human monocyte-derived DC. The enhanced level of CD83 cell surface expression in mDC resulted predominantly from increased protein synthesis, and in addition from regulated intracellular transport of CD83 protein. An internal pool of CD83 protein is present in immature DC (iDC). Although CD83 protein in iDC and in mDC was localized in the Golgi compartment and in recycling endosomes, only in mature cells did CD83 co-localize with MHC class II molecules in endocytic vesicles. CD83 cell surface expression on iDC was induced by inhibition of endocytosis. This result could be explained by CD83 cycling between endosomes and the cell surface in iDC. The mDC also rapidly internalized membrane-bound CD83 protein. Furthermore, a thiol protease inhibitor and specific cathepsin inhibitors impaired CD83 up-regulation in DC, indicating a role of endosomal proteases in the maturation-induced exposure of CD83 on the plasma membrane.
authors.affiliation: Department of Dermatology, Friedrich-Wilhelms-University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Klein
authors.forename: Susanne
authors.initials: S
authors.lastname: Koch
authors.forename: Bodo
authors.initials: B
authors.lastname: Borm
authors.forename: Jürgen
authors.initials: J
authors.lastname: Neumann
authors.forename: Volker
authors.initials: V
authors.lastname: Herzog
authors.forename: Norbert
authors.initials: N
authors.lastname: Koch
authors.forename: Thomas
authors.initials: T
authors.lastname: Bieber
mesh_terms: D015703:Antigens, CD; D003713:Dendritic Cells / Q000276:immunology*; D011992:Endosomes / Q000276:immunology; D006056:Golgi Apparatus / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D007136:Immunoglobulins / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000276:immunology*; D013997:Time Factors; D000097802:CD83 Antigen
chemical_list: D015703:Antigens, CD; D000949:Histocompatibility Antigens Class II; D007136:Immunoglobulins; D008562:Membrane Glycoproteins; D000097802:CD83 Antigen