title: CD83 influences cell-surface MHC class II expression on B cells and other antigen-presenting cells.
abstract: CD83 is a member of the Ig superfamily expressed primarily by mature dendritic cells (DCs). In mice, CD83 expression by thymic stromal cells regulates CD4(+) T cell development, with CD83(-/-) mice demonstrating dramatic reductions in both thymus and peripheral CD4(+) T cells. In this study, CD83 expression was also found to affect MHC class II antigen expression within the thymus and periphery. CD83 deficiency reduced cell-surface class II antigen expression by 25-50% on splenic B cells and DCs, thymic epithelial cells and peritoneal macrophages. Reduced class II expression was a stable and intrinsic property that resulted from increased internalization of class II from the surface of CD83(-/-) B cells. Otherwise, class II antigen transcription, intracellular expression, heterodimer structure, antigen processing and antigen presentation were normal. Reduced class II antigen expression was not the primary cause of the CD83(-/-) phenotype since thymocyte and peripheral T cell development was normal in class II(+/-) mice. Comparable blocks in CD4(+) thymocyte development were also observed in CD83(-/-) and CD83(-/-)class II(+/-) littermates. TCR and CD69 expression patterns in CD83(-/-) mice further suggested that double-positive thymocytes proceed through the class II-dependent stages of positive selection in the absence of CD83. These studies further emphasize a role for CD83 in lymphocyte development and immune regulation and reveal an unexpected role for CD83 expression in influencing cell-surface MHC class II turnover.
authors.affiliation: Department of Dermatology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kuwano
authors.forename: Charlene M
authors.initials: CM
authors.lastname: Prazma
authors.forename: Norihito
authors.initials: N
authors.lastname: Yazawa
authors.forename: Rei
authors.initials: R
authors.lastname: Watanabe
authors.forename: Nobuko
authors.initials: N
authors.lastname: Ishiura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kumanogoh
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Okochi
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Tamaki
authors.forename: Manabu
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Tedder
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000938:Antigen-Presenting Cells / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000378:metabolism*; D007136:Immunoglobulins / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000276:immunology*; D051379:Mice; D008817:Mice, Mutant Strains; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D000097802:CD83 Antigen