title: K cell activity of murine-cultured lymphocytic leukemic cell line independent of other Fc receptor functions.
abstract: A murine-cultured lymphocytic leukemic cell line, SC-1, showed remarkable cytotoxicity against 51Cr-labeled rabbit erythrocytes as target cells in the presence of antitarget antibodies in vitro. This cytotoxicity was complement independent, inhibited by the addition of aggregated human gamma-globulin, and reduced by pepsin digestion of antitarget IgG. Moreover, SC-1 cells also induced cytotoxicity to trinitrophenyl-modified rabbit erythrocytes in the presence of antitrinitrophenyl antibodies but not unmodified rabbit erythrocytes used as bystander cells. SC-1 cells which showed such K cell activity, however escaped from Fc receptor detection by erythrocyte antibody rosettes and FITC-conjugated aggregated human gamma-globulin binding. In morphological studies using the scanning electron microscope, SC-1 cells to induce cytotoxicity through a light attachment to target cells via 'point contact' of the microvilli. From these findings the characteristics of Fc receptors on effector cells in the mechanism of antibody-dependent cellular cytotoxicity was discussed.
mesh_terms: D000818:Animals; D000906:Antibodies; D000920:Antibody-Dependent Cell Cytotoxicity; D002460:Cell Line; D004912:Erythrocytes; D007694:Killer Cells, Natural; D007942:Leukemia, Experimental; D007945:Leukemia, Lymphoid / Q000097:blood*; D008214:Lymphocytes / Q000276:immunology* / Q000648:ultrastructure; D051379:Mice; D011961:Receptors, Fc / Q000276:immunology; D014301:Trinitrobenzenes
chemical_list: D000906:Antibodies; D011961:Receptors, Fc; D014301:Trinitrobenzenes