title: Activation of lymphocytes by anti-CD3 single-chain antibody dimers expressed on the plasma membrane of tumor cells.
abstract: Activation of cytotoxic T cells without MHC restriction was attempted by expressing single-chain antibodies (scFv) against CD3 on the surface of tumor cells. A chimeric protein consisting of a scFv of mAb 145.2C11, the hinge-CH2-CH3 region of human IgG1, and the transmembrane and cytosolic domains of murine CD80 formed disulfide-linked dimers on the plasma membrane of cells and specifically bound lymphocytes. Anti-CD3 scFv dimers expressed on the cell surface induced CD25 (IL-2 receptor alpha-chain) expression and proliferation of splenocytes. CT26 tumor cells engineered to express surface scFv dimers (CT26/2C11) also induced potent lymphocyte cytotoxicity with or without addition of exogenous IL-2. Splenocytes activated by CT26/2C11 cells also killed wild-type CT26 cells, indicating that activated splenocytes could kill bystander tumor cells. Immunization of BALB/c mice with irradiated CT26/2C11 cells did not protect against a lethal challenge of CT26 cells, suggesting that systemic immunity was not induced. However, the growth of CT26 tumors containing 50% CT26/2C11 cells was significantly retarded compared with CT26 tumors, whereas CT26/2C11 tumors did not grow in syngeneic mice. These results suggest that expression of anti-CD3 scFv dimers on tumors may form the basis for a novel therapeutic strategy for tumors that exhibit defects in antigen processing or presentation. Gene Therapy (2000) 7, 339-347.
authors.affiliation: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, ROC.
authors.forename: K W
authors.initials: KW
authors.lastname: Liao
authors.forename: Y C
authors.initials: YC
authors.lastname: Lo
authors.forename: S R
authors.initials: SR
authors.lastname: Roffler
mesh_terms: D000818:Animals; D017252:CD3 Complex / Q000276:immunology*; D002462:Cell Membrane / Q000276:immunology; D003110:Colonic Neoplasms / Q000276:immunology*; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000276:immunology; D007167:Immunotherapy / Q000379:methods; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D011993:Recombinant Fusion Proteins / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D017252:CD3 Complex; D007135:Immunoglobulin Variable Region; D011993:Recombinant Fusion Proteins