title: The macrophage as a cytotoxic effector cell.
abstract: Cells of the macrophage lineage possess three different mechanisms allowing them to act as cytotoxic effector cells: lymphokine-activated macrophages kill extracellularly proliferating target cells, preferentially tumor targets, and intracellularly parasitic microorganism like Salmonella, Toxoplasma, Leishmania, and others. Young macrophages and macrophage precursor cells kill antibody coated nucleated target cells. Finally nonadherent, nonphagocytic macrophage precursor cells, released from the bone marrow to sites of inflammation and to the peripheral blood show strong natural killer activity. For the various macrophage functions different subpopulations seem to be responsible as can be seen from data with antimacrophage monoclonal antibodies recognizing and eliminating functionally active subpopulations. The cells of the macrophage system, with their three cytotoxic effector mechanisms which cooperate and enhance each other, are very likely to play an important role in the cytotoxic defense system of the body.
mesh_terms: D000818:Animals; D000920:Antibody-Dependent Cell Cytotoxicity; D003602:Cytotoxicity, Immunologic; D008222:Lymphokines / Q000494:pharmacology; D008262:Macrophage Activation; D008263:Macrophage Migration-Inhibitory Factors / Q000494:pharmacology; D016215:Macrophage-Activating Factors; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D009000:Monocytes / Q000502:physiology
chemical_list: D008222:Lymphokines; D008263:Macrophage Migration-Inhibitory Factors; D016215:Macrophage-Activating Factors