title: Characterization of K-cell activity by use of depletion experiments.
abstract: Normal human blood lymphocytes with affinity for ox red cells sensitized with IgG antibody, for normal or papain-treated sheep red cells and for ox red cells coated with mouse complement were used for rosette formation and the rosetting cells separated by density gradient centrifugation on Ficoll/hypaque. The non-rosetting cells at the interface were collected and compared with cell suspensions before treatment for direct and antibody-dependent cytotoxicity of human target cells. Depletion of Fc-receptor-bearing lymphocytes strongly decreased antibody-dependent cell-mediated cytotoxicity; reduction in the number (or depletion) of T cells and cells with C'3 receptor had no effect, showing the same or enhanced K-cell activity. It is concluded that one type of K or killer cell has Fc receptors but lacks C'3 receptors.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001665:Binding Sites; D002499:Centrifugation, Density Gradient; D003176:Complement C3; D003601:Cytotoxicity Tests, Immunologic; D005362:Ficoll; D006801:Humans; D007104:Immune Adherence Reaction; D007111:Immunity, Cellular; D007141:Immunoglobulin Fc Fragments; D008212:Lymphocyte Depletion; D012756:Sheep / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D003176:Complement C3; D007141:Immunoglobulin Fc Fragments; D005362:Ficoll