title: Mediation of macrophage cytolytic and phagocytic activities by antibodies of different classes and class-specific Fc-receptors.
abstract: The classes of antibodies that mediate the phagocytosis and cytolysis of 51Cr-labeled chicken erythrocytes by IC-21 macrophages, an established line of mouse peritoneal macrophages, were identified. The phagocytic activity of IC-21 macrophages, as determined by a functional inhibition assay with mouse myeloma proteins, depended mainly on IgM and IgG2a antibodies and to a lesser extent on IgG2b antibodies. Extracellular cytolysis of target cells was mediated solely by IgG2b antibodies. These results correlate with the previously documented specificities of discrete Fc-receptors for IgG2a and IgG2b immunoglobulins on IC-21 cells. Thus, phagocytosis and cytolysis appear to be mediated by antibodies of different classes operating through separate and distinct sites on the surface of IC-21 macrophages.
mesh_terms: D000918:Antibody Specificity; D001665:Binding Sites; D002478:Cells, Cultured; D006461:Hemolysis; D007122:Immunoelectrophoresis; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G / Q000302:isolation & purification; D007075:Immunoglobulin M; D008264:Macrophages / Q000276:immunology*; D009194:Myeloma Proteins / Q000276:immunology; D010587:Phagocytosis
chemical_list: D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D009194:Myeloma Proteins