title: Dendritic cells derived from bone marrow cells fail to acquire and present major histocompatibility complex antigens from other dendritic cells.
abstract: Dendritic cells stimulate primary T-cell responses and a major activation route is via presentation of antigens pre-processed by other dendritic cells. This presentation of pre-processed antigens most likely proceeds through transfer of functional major histocompatibility complex (MHC) antigens through exosomes, 'live nibbling' or apoptotic vesicles. We hypothesized that not all dendritic cell populations may both donate MHC antigen to dendritic cells and present antigens acquired from other dendritic cells. All populations tested, including those derived from bone marrow precursor cells stimulated primary, allogeneic T-cell responses and acted as accessory cells for mitogen stimulation. Populations of responder type, splenic dendritic cells promoted allogeneic responses indirectly but those derived from bone marrow cells blocked rather than promoted T-cell proliferation. To identify mechanisms underlying this difference we studied transfer of I-A antigens between cells. Active, two-way transfer of allogeneic I-A occurred between splenic primary antigen presenting cells including CD8alpha+ lymphoid dendritic cells, CD8alpha- myeloid dendritic cells and B220+ cells; all these cell types donated as well as acquired MHC molecules. By contrast, the bone marrow-derived dendritic cells donated I-A antigens but acquired negligible amounts. Thus, dendritic cells derived directly from bone marrow cells may stimulate primary T-cell responses through transferring functional MHC to other dendritic cells but may not be able to acquire and present antigens from other dendritic cells. The evidence suggests that T-cell activation may be blocked by the presence of dendritic cells that have not matured through lymphoid tissues which are unable to acquire and present antigens pre-processed by other dendritic cells.
authors.affiliation: Antigen Presentation Research Group, Imperial College London, North West London Hospitals Campus, Harrow, London, UK.
authors.forename: Penelope A
authors.initials: PA
authors.lastname: Bedford
authors.forename: Fiona
authors.initials: F
authors.lastname: Burke
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Stagg
authors.forename: Stella C
authors.initials: SC
authors.lastname: Knight
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D017951:Antigen Presentation / Q000276:immunology*; D001854:Bone Marrow Cells / Q000276:immunology*; D017252:CD3 Complex / Q000276:immunology; D002478:Cells, Cultured; D003208:Concanavalin A / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D008285:Major Histocompatibility Complex / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D014302:Trinitrobenzenesulfonic Acid / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D000949:Histocompatibility Antigens Class II; D003208:Concanavalin A; D014302:Trinitrobenzenesulfonic Acid