title: Costimulation regulates the kinetics of interleukin-2 response to bacterial superantigens.
abstract: The aim of this study was to investigate the mechanisms by which B7-related costimulatory molecules (CD80, CD86) increase T-cell responsiveness to extracellular ligands. As a model study, the in vitro response of purified splenic CD4+ T cells to a bacterial superantigen, SEB, was characterized. Previous analysis of this experimental model led us to conclude that expression of B7-related molecules is strictly required in order to activate CD4+ T cells in the presence of bacterial superantigens. In the present report, we demonstrate that antigen-presenting cell-derived costimulatory signals regulate the kinetics of interleukin-2 (IL-2) production by SEB-activated splenic CD4+ T cells. Indeed, experiments performed with purified subpopulations of antigen-presenting cells and using B7-transfected cell lines indicated that increased levels of CD80 and/or CD86 cell surface expression is associated with a faster kinetics of IL-2 production in response to SEB. Accordingly, blocking of CD80 or CD86-derived signals by specific monoclonal antibodies led to a slower kinetics of IL-2 production in response to SEB. Thus these data demonstrate that similar strength of signal through the T-cell receptor can lead to immune responses displaying distinct kinetics depending on the level of costimulatory ligands on APC.
authors.affiliation: Département de Biologie Moléculaire, Université Libre de Bruxelles, Rhode-St-Genèse, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: Muraille
authors.forename: S
authors.initials: S
authors.lastname: Devos
authors.forename: K
authors.initials: K
authors.lastname: Thielemans
authors.forename: J
authors.initials: J
authors.lastname: Urbain
authors.forename: M
authors.initials: M
authors.lastname: Moser
authors.forename: O
authors.initials: O
authors.lastname: Leo
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology*; D018122:B7-1 Antigen / Q000276:immunology*; D051940:B7-2 Antigen; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D005260:Female; D007376:Interleukin-2 / Q000378:metabolism*; D007700:Kinetics; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018089:Superantigens / Q000494:pharmacology*
chemical_list: D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497965:Cd86 protein, mouse; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D018089:Superantigens