title: Novel pathways of antigen presentation for the maintenance of memory.
abstract: Follicular dendritic cells (FDC) store native antigen for long periods in lymphoid follicles and so provide a source of continued stimulation for specific B cells. The expression of MHC class II by FDC suggested they might act as antigen-presenting cells for MHC class II-restricted T cells. We show here, however, that the MHC class II molecules found on their surface are not synthesized by the FDC but are picked up from surrounding B cells in germinal centres. Although FDC by themselves cannot present native antigen to T cells, acquired MHC class II-peptide complexes can be recognized by T cells. The true physiological role of FDC seems to be as long-term antigen depots. We demonstrate that antigen localized onto FDC in vivo can be retrieved by antigen-specific B cells, which in turn process and present it to T cells. These presentation pathways are likely to be crucial in both the maintenance of long-term immune responses and the continued survival of memory cells.
authors.affiliation: Basel Institute for Immunology, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Gray
authors.forename: M
authors.initials: M
authors.lastname: Kosco
authors.forename: B
authors.initials: B
authors.lastname: Stockinger
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D001853:Bone Marrow / Q000276:immunology; D002678:Chimera / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D004140:Dinitrophenols / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006433:Hemocyanins / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007114:Immunization; D007156:Immunologic Memory; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D010047:Ovalbumin / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: C042158:2,4-dinitrophenyl keyhole limpet hemocyanin; D000911:Antibodies, Monoclonal; D004140:Dinitrophenols; D000949:Histocompatibility Antigens Class II; C045521:dinitrophenol-ovalbumin; D010047:Ovalbumin; D006433:Hemocyanins