title: Dendritic cells, but not macrophages or B cells, activate major histocompatibility complex class II-restricted CD4+ T cells upon immune-complex uptake in vivo.
abstract: Professional antigen-presenting cells (APC) are able to process and present exogenous antigen leading to the activation of T cells. Antigen-immunoglobulin (Ig)G complexes (IC) are much more efficiently processed and presented than soluble antigen. Dendritic cells (DC) are known for their ability to take up and process immune complex (IC) via FcgammaR, and they have been shown to play a crucial role in IC-processing onto major histocompatibility complex (MHC) class I as they contain a specialized cross-presenting transport system required for MHC class I antigen-processing. However, the MHC class II-antigen-processing pathway is distinct. Therefore various other professional APC, like macrophages and B cells, all displaying FcgammaR, are thought to present IC-delivered antigen in MHC class II. Nonetheless, the relative contribution of these APC in IC-facilitated antigen-presentation for MHC class II in vivo is not known. Here we show that, in mice, both macrophages and DC, but not B cells, efficiently capture IC. However, only DC, but not macrophages, efficiently activate antigen-specific MHC class II restricted CD4(+) T cells. These results indicate that mainly DC and not other professional APC, despite expressing FcgammaR and MHC class II, contribute significantly to IC-facilitated T cell activation in vivo under steady-state conditions.
authors.affiliation: Department of Rheumatology, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Judith M H
authors.initials: JM
authors.lastname: de Jong
authors.forename: Danita H
authors.initials: DH
authors.lastname: Schuurhuis
authors.forename: Andreea
authors.initials: A
authors.lastname: Ioan-Facsinay
authors.forename: Mick M
authors.initials: MM
authors.lastname: Welling
authors.forename: Marcel G M
authors.initials: MG
authors.lastname: Camps
authors.forename: Ellen I H
authors.initials: EI
authors.lastname: van der Voort
authors.forename: Tom W J
authors.initials: TW
authors.lastname: Huizinga
authors.forename: Ferry
authors.initials: F
authors.lastname: Ossendorp
authors.forename: J Sjef
authors.initials: JS
authors.lastname: Verbeek
authors.forename: René E M
authors.initials: RE
authors.lastname: Toes
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D049109:Cell Proliferation; D003713:Dendritic Cells / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D007074:Immunoglobulin G / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C
chemical_list: D000936:Antigen-Antibody Complex; D000949:Histocompatibility Antigens Class II; D007074:Immunoglobulin G