title: Functional characterization of lymphokines from the EL-4 T cell line that activate macrophages for nonspecific tumor cytotoxicity.
abstract: Culture fluids from a phorbol myristate acetate-stimulated EL-4 thymoma cell line were previously found to activate mouse macrophages to become nonspecifically tumoricidal. By gel filtration, 23,000- and 45,000-MW peaks were identified. In this study we compared EL-4 culture fluid activity with that obtained from antigen-stimulated mouse spleen cells. By four criteria, functional activity from the two sources was comparable: 1) Macrophage activation could be separated temporally into two steps, priming and triggering. 2) Macrophages activated by the fluids exhibited peak cytotoxic activity within 5-9 hr; no cytotoxic activity was demonstrable if addition of target cells was delayed 14 hr. 3) Mouse peritoneal exudate macrophages, but not resident macrophages, became cytotoxic after a 5-hr incubation with culture fluids. 4) Macrophages from certain strains of mice were incapable of activation; the same pattern of strain unresponsiveness was observed with both EL-4 and spleen cell culture fluids. Thus, it is likely that the two EL-4 products and the mouse spleen cell lymphokine activate the same cytotoxic mechanism.
mesh_terms: D000818:Animals; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D007700:Kinetics; D008222:Lymphokines / Q000378:metabolism*; D008262:Macrophage Activation; D016215:Macrophage-Activating Factors; D008264:Macrophages / Q000145:classification / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D013945:Thymoma / Q000473:pathology; D013953:Thymus Neoplasms / Q000276:immunology / Q000473:pathology
chemical_list: D008222:Lymphokines; D016215:Macrophage-Activating Factors