title: Adoptive immune therapy in mice bearing poorly immunogenic metastases, using T lymphocytes stimulated in vitro against highly immunogenic mutant sublines.
abstract: MDW3, a highly immunogenic and non-tumorigenic (tum-) mutant of the poorly immunogenic metastatic murine tumor called MDAY-D2, has been employed in an immune therapy scheme for the treatment of widespread established visceral MDAY-D2 metastases in syngeneic mice. MDW3 was selected from a mutagenized population of MDAY-D2 cells for the ability to grow in the presence of toxic concentrations of wheat-germ agglutinin (WGA) in vitro. The mutant expresses a common tumor-associated antigen (TAA) present on MDAY-D2 as well as a new antigen whose presence enhances the anti-TAA cell-mediated immune response in vivo and in mixed lymphocyte tumor cultures (MLTC) in vitro. For immune therapy, spleen cells from DBA/2 mice which had rejected an inoculum of MDW3 cells were restimulated in MLTC and injected i.v. into MDAY-D2 tumor-bearing mice. Two protocols were used. In the first, mice were given an i.v. injection of 10(3) MDAY-D2 cells ("artificial metastasis") and subsequently treated with 400 R whole-body irradiation and MDW3-stimulated T cells. Such mice had a 75% long-term survival rate, whereas 400 R alone, or no treatment, resulted in 25% and 0% long-term survivors, respectively. In the second protocol, treatment of mice bearing a 12-day-old subcutaneous MDAY-D2 tumor by surgical removal of the solid tumor, 400 R whole-body irradiation, and systemic administration of MDW3-stimulated spleen cells, resulted in a 75-100% survival rate, whereas omitting any part of the treatment resulted in 0-50% survival rates. The treatment increased splenic anti-TAA CTL activity, and the mice acquired immunity against the new antigen on MDW3, suggesting that the injected lymphocytes were proliferating in the host. The optimal combination of resection, whole-body irradiation and passive infusion of MDW3-stimulated spleen cells was ineffective when used on mice bearing a tumor-antigen-loss variant of MDAY-D2, suggesting that success of our immune therapy protocol required specific recognition of the tumor-associated antigen of MDAY-D2.
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000633:toxicity; D007116:Immunization, Passive; D007167:Immunotherapy; D051379:Mice; D008811:Mice, Inbred DBA; D016685:Mitomycin; D008937:Mitomycins / Q000633:toxicity; D009154:Mutation; D009362:Neoplasm Metastasis / Q000473:pathology*; D009374:Neoplasms, Experimental / Q000276:immunology* / Q000473:pathology; D013154:Spleen / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000903:Antibiotics, Antineoplastic; D008937:Mitomycins; D016685:Mitomycin