title: T cell activation by monoclonal antibodies bound to tumor cells by a cell surface displayed single-chain antibody.
abstract: Tumor cells often lack the costimulatory molecules necessary for T cell activation. However, the transformation of cells with more than one stimulatory molecule is a difficult procedure. We therefore developed a retroviral vector for the expression of a cell membrane anchored single-chain antibody fragment (scFv) directed against the hapten 4-ethoxymethylene-2-phenyl-2-oxazoline-5-one (phOx). Proteins and peptides can be readily modified with this hapten, thus, enabling them to be bound to cells with the cell surface displayed anti-phOx scFv. To test combinations of surface-bound stimulatory molecules on T cell activation, SK-Mel63 human melanoma cells expressing the membrane anchored anti-phOx scFv were incubated with phOx-labeled mAbs against CD3, CD28 and CD5. Cells presenting a given mixture of modified anti-CD3 and anti-CD28 molecules stimulated T cell activation better than any single antibody and a given mixture of anti-CD3, anti-CD28 and anti-CD5 provided a stimulatory response higher than the best double combination. However, the relative concentrations are very important and must be carefully chosen. Concentrations of antibodies giving good T cell responses when used alone can block synergistic effects.
authors.affiliation: Diagnostics and Experimental Therapy Programme, German Cancer Research Center, Heidelberg.
authors.forename: H J
authors.initials: HJ
authors.lastname: Rode
authors.forename: U
authors.initials: U
authors.lastname: Moebius
authors.forename: M
authors.initials: M
authors.lastname: Little
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology; D018106:CD28 Antigens / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D018956:CD5 Antigens / Q000276:immunology; D002455:Cell Division; D004357:Drug Synergism; D015870:Gene Expression; D006241:Haptens / Q000276:immunology*; D006801:Humans; D007128:Immunoglobulin Fragments / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D010080:Oxazoles / Q000276:immunology*; D010081:Oxazolone; D013601:T-Lymphocytes / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: C119678:4-ethoxymethylene-2-phenyl-2-oxazoline-5-one; D000911:Antibodies, Monoclonal; D018122:B7-1 Antigen; D018106:CD28 Antigens; D017252:CD3 Complex; D018956:CD5 Antigens; D006241:Haptens; D007128:Immunoglobulin Fragments; D010080:Oxazoles; C055966:immunoglobulin Fv; D010081:Oxazolone