title: Protective and therapeutic immunity against leukemia induced by irradiated B7-1 (CD80)-transduced leukemic cells.
abstract: B7 molecules provide an important co-stimulatory signal for T cell receptor/CD3-mediated T cell activation via binding to their cognate receptors, CD28 and CTLA-4. We have introduced B7-1 (CD80) into M1 cells, spontaneously occurring mouse myelocytic leukemic cells, and assessed its potential to induce antitumor immunity to leukemia cells. Syngeneic, immunocompetent SL mice receiving two independent B7-1-transduced monoclonal sublines, M1-B7-1/F/clone F20 and M1-B7-1/F/clone F7, were rejected in 57% and 43% of SL mice, respectively. In vivo depletion of T cell subsets showed that both CD4+ and CD8 T cells were indispensable for the B7-1-dependent anti-leukemic immunity. Although a single exposure of irradiated monoclonal M1-B7/1/F cells was not fully effective, multiple exposures induced protective immunity against subsequent challenge with parental M1 cells. Furthermore, multiple vaccinations with irradiated monoclonal M1-B7-1/F/clone F7 cells could cure 67% of mice previously injected with a lethal number of M1 cells. These results emphasize that multiple exposures of irradiated B7-1-transduced myeloid leukemic cells can induce protective and therapeutic immunity against leukemia and that B7-1-mediated gene therapy may have therapeutic efficacy for patients with acute myelocytic leukemia.
authors.affiliation: Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Hirano
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Azuma
authors.forename: K
authors.initials: K
authors.lastname: Okumura
authors.forename: Y
authors.initials: Y
authors.lastname: Yazaki
authors.forename: H
authors.initials: H
authors.lastname: Yagita
authors.forename: H
authors.initials: H
authors.lastname: Hirai
mesh_terms: D000818:Animals; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019556:COS Cells; D005434:Flow Cytometry; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D007111:Immunity, Cellular; D007167:Immunotherapy / Q000379:methods*; D007951:Leukemia, Myeloid / Q000276:immunology / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010957:Plasmids / Q000235:genetics; D012190:Retroviridae / Q000235:genetics; D016019:Survival Analysis
chemical_list: D018122:B7-1 Antigen