title: The strategy of T cell antigen-presenting cell encounter in antigen-draining lymph nodes revealed by imaging of initial T cell activation.
abstract: The development of an immune response critically relies on the encounter of rare antigen (Ag)-specific T cells with dendritic cells (DCs) presenting the relevant Ag. How two rare cells find each other in the midst of irrelevant other cells in lymph nodes (LNs) is unknown. Here we show that initial T cell activation clusters are generated near high endothelial venules (HEVs) in the outer paracortex of draining LNs by retention of Ag-specific T cells as they exit from HEVs. We further show that tissue-derived DCs preferentially home in the vicinity of HEVs, thus defining the site of cluster generation. At this location DCs efficiently scan all incoming T cells and selectively retain those specific for the major histocompatibility complex-peptide complexes the DCs present. Such strategic positioning of DCs on the entry route of T cells into the paracortex may foster T cell-DC encounter and thus optimize initial T cell activation in vivo.
authors.affiliation: Centre d'Immunologie de Marseille-Luminy, INSERM/Centre National de la Recherche Scientifique, Université de la Méditerranée, Parc Scientifique de Luminy, Case 906, 13288 Marseille Cedex 09, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Bajénoff
authors.forename: Samuel
authors.initials: S
authors.lastname: Granjeaud
authors.forename: Sylvie
authors.initials: S
authors.lastname: Guerder
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D001854:Bone Marrow Cells / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology; D004730:Endothelium, Vascular / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D009113:Muramidase / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014699:Venules / Q000276:immunology
chemical_list: D011948:Receptors, Antigen, T-Cell; D009113:Muramidase