T cell-mediated immunity to oncornavirus-induced tumors. III. Specific and nonspecific suppression in tumor-bearing mice.
A strong cell-mediated immune response against Friend, Moloney, Rauscher virus-induced (FMR) cell surface antigens has been demonstrated previously in mice which reject oncornavirus-induced tumors. In order to identify an eventual suppressor mechanism in animals with progressively growing tumors, experiments were initiated in C57BL/6 mice bearing either a murine sarcoma virus (MSV) tumor or Moloney virus-induced lymphoma (MBL2). Progressive tumor growth was induced (a) in viremic animals first infected with Moloney murine leukemia virus (M.Mu LV), then inoculated as adult with MSV; (b) in nonviremic animals injected with MBL2 lymphoma cells. In the absence of tumor cells, viremia induces specific tolerance for which there is no evidence for suppressor cells. In tumor-bearing mice, specific suppressor T cells are detected which are able to inhibit the generation of anti-FMR cytolytic T lymphocytes in vitro and enhance the tumor growth in vivo. In addition to the specific suppressor T cells, a nonspecific suppressive activity mediated by metastatic T lymphoma cells is demonstrated in the spleens of lymphoma-bearing animals. The respective role of the virus and tumor cells in the induction of tolerance to M.MuLV-induced antigens, and their relationship to other components of the specific cell-mediated immune response is discussed.
D000818:Animals; D000961:Antilymphocyte Serum / Q000494:pharmacology; D002471:Cell Transformation, Neoplastic; D003165:Complement System Proteins; D003602:Cytotoxicity, Immunologic; D007108:Immune Tolerance; D007111:Immunity, Cellular; D008223:Lymphoma / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D012190:Retroviridae; D012513:Sarcoma, Experimental / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
D000961:Antilymphocyte Serum; D003165:Complement System Proteins