title: Mechanisms by which tumors avoid destruction by the immune system BCG-catalyzed increase in IgG and IgA blocking activity of lymphocyte-mediated cytotoxicity.
abstract: The immunoglobulin IgM fraction from the serum of one week sarcoma-bearing BALB/c mice increased, the IgG and IgA fractions from the same animal had no effect on the lymphocytemediated cytotoxic release of 51Cr from 51Cr-labelled sarcoma cells. These latter two immunoglobulin fractions from serum of 14 Days, or more, sarcoma-bearing mice inhibited the lymphocyte-mediated cytotoxic activity. The IgA, IgG or IgM fractions from mice inoculated with bacillus Calmette-Guerin (BCG) had no effect, but if these same animals were inoculated with viable sarcoma cells (10(2) to 10(6) cells per mouse) IgG and IgA fractions inhibited the lymphocyte-mediated cytotoxic activity. The magnitude of inhibition was greatest with sera or IgG from tumor-bearing BCG-treated animals.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000951:Antigens, Neoplasm; D001500:BCG Vaccine; D002417:Cattle; D002860:Chromium Radioisotopes; D003601:Cytotoxicity Tests, Immunologic; D007111:Immunity, Cellular; D007070:Immunoglobulin A / Q000096:biosynthesis / Q000378:metabolism; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D008214:Lymphocytes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009163:Mycobacterium bovis / Q000276:immunology*; D012513:Sarcoma, Experimental / Q000276:immunology*; D013154:Spleen / Q000276:immunology
chemical_list: D000951:Antigens, Neoplasm; D001500:BCG Vaccine; D002860:Chromium Radioisotopes; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M