title: Regressor serum factor-dependent nonspecific killers in tumor-bearing mice.
abstract: Spleen cells obtained from C3H/He or C57BL/6 mice bearing syngeneic ascitic tumor cells in the early stage of tumor progression had activity to lyse various tumor cells in vitro when serum from MM2-regressor C3H/He was added to the reaction mixture. The serum component responsible for the reaction was of non-immunoglobulin nature. The serum factor-dependent cytotoxic cells were Thy-1-positive cells which were not adherent to nylon wool or Sephadex G-10 and were not natural killer cells. Allogeneic tumor cells and syngeneic tumor cells of near-tetraploid chromosomes were susceptible to such lysis whereas syngeneic near-diploid cells were resistant. The serum factor was absorbed by susceptible cells and not by resistant cells.
mesh_terms: D000818:Animals; D000920:Antibody-Dependent Cell Cytotoxicity; D001201:Ascites / Q000097:blood; D002448:Cell Adhesion / Q000187:drug effects; D003165:Complement System Proteins / Q000494:pharmacology; D007106:Immune Sera; D007518:Isoantibodies / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000145:classification / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008815:Mice, Inbred Strains; D009365:Neoplasm Regression, Spontaneous; D009374:Neoplasms, Experimental / Q000097:blood*; D013154:Spleen / Q000166:cytology
chemical_list: D007106:Immune Sera; D007518:Isoantibodies; C035678:anti-Thy antibody; D003165:Complement System Proteins