title: Molecular characterization of U937-dependent T-cell co-stimulation.
abstract: U937 cells provide a co-stimulatory signal for CD3-mediated T-cell activation which is independent of the CD28/CD80/CD86 interaction. This study set out to identify which molecules contribute to this co-stimulatory activity. Monoclonal antibodies (mAb) to the known accessory molecules CD11a, CD18, CD54 and CD45, all inhibited T-cell proliferation. Although CD11a/18 mAb inhibited U937/T-cell cluster formation as well as proliferation, CD45 enhanced the size of the clusters formed, suggesting that this was not the only mechanism of inhibition. The alternative co-stimulatory pathway provided by U937 cells preferentially stimulated a response in the CD18+ T-cell population, and this reflected the reduced sensitivity of CD8+ T cells to CD28-mediated activation. Monoclonal antibodies to three molecules, CD53, CD98 and CD147, also inhibited U937-dependent T-cell proliferation. The mAb to CD98 and CD147 were inhibitory when prepulsed on to the U937 cells, suggesting an effect mediated by these molecules on the antigen-presenting cell.
authors.affiliation: Department of Immunology, Windeyer Institute of Medical Sciences, University College London, London, UK.
authors.forename: T J
authors.initials: TJ
authors.lastname: Stonehouse
authors.forename: V E
authors.initials: VE
authors.lastname: Woodhead
authors.forename: P S
authors.initials: PS
authors.lastname: Herridge
authors.forename: H
authors.initials: H
authors.lastname: Ashrafian
authors.forename: M
authors.initials: M
authors.lastname: George
authors.forename: B M
authors.initials: BM
authors.lastname: Chain
authors.forename: D R
authors.initials: DR
authors.lastname: Katz
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD / Q000276:immunology; D018821:CD18 Antigens / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002352:Carrier Proteins / Q000276:immunology; D002448:Cell Adhesion / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D027261:Fusion Regulatory Protein-1; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000276:immunology; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology; D014066:Palatine Tonsil / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D020298:U937 Cells / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018821:CD18 Antigens; D017252:CD3 Complex; D002352:Carrier Proteins; D027261:Fusion Regulatory Protein-1; D016169:Lymphocyte Function-Associated Antigen-1; D018799:Intercellular Adhesion Molecule-1; D017493:Leukocyte Common Antigens