title: Correlation between natural and antibody-dependent cell-mediated cytotoxicity against tumor targets in the mouse. II. Characterization of the effector cells.
abstract: Direct comparison of the effector cells mediating natural killer (NK) activity against mouse tumor cells and antibody-dependent cell-mediated cytotoxicity (ADCC) against mouse tumor target cells coated with alloantisera indicated that NK cells and K-cells (effector cells mediating ADCC) may belong to the same subpopulation of lymphocytes, but they have a different mechanism of killing. Effector cells mediating NK activity and ADCC were nonadherent, nonphagocytic Fc receptor-bearing cells that sediment at 3.5-4.5 mm/hour. Treatment with anti-Thy 1.2 serum in the absence of complement resulted in an increase of NK activity, whereas this treatment caused a substantial loss in ADCC. Both NK activity and ADCC were equally sensitive to the in vivo or in vitro effects of X-irridiation. In vivo inoculations of high doses of hydrocortisone resulted in a reduction of NK activity, but ADCC was not affected. NK cells were trypsin-sensitive, with a profound decrease in the cytolytic activity being observed in a 4-hour 51Cr release assay. The activity, however, could be recovered after overnight incubation at 37 degrees C. Trypsin treatment did not inhibit ADCC as measured by the 18-hour assay.
mesh_terms: D000818:Animals; D000920:Antibody-Dependent Cell Cytotoxicity; D000961:Antilymphocyte Serum / Q000494:pharmacology; D006854:Hydrocortisone / Q000494:pharmacology; D007113:Immunity, Innate; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology* / Q000528:radiation effects; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008808:Mice, Inbred CBA; D009374:Neoplasms, Experimental / Q000276:immunology*; D011961:Receptors, Fc; D013601:T-Lymphocytes / Q000276:immunology; D014357:Trypsin / Q000494:pharmacology
chemical_list: D000961:Antilymphocyte Serum; D011961:Receptors, Fc; D014357:Trypsin; D006854:Hydrocortisone