title: A quantitative fluorometric assay for detection and characterization of Fc receptors.
abstract: A new quantitative fluorometric binding assay that uses fluoresceinated aggregated IgG is proposed for the study of Fc receptors. The method was compared with a radiolabeling binding assay on three well characterized murine cell lines (38C-13, EL4, and BW). The apparent association constant of the binding and the amount of aggregated IgG bound per cell at saturation were calculated. The fluorometric assay enables the detection of 5 X 10(-10) M bound aggregated IgG. Inhibition studies with monomeric IgG, reduced and alkylated aggregated IgG, and aggregated F(ab')2 fragments of IgG confirmed the specificity of the assay. Staphylococcal protein A inhibited the binding of the aggregated IgG to Fc receptors.
mesh_terms: D000918:Antibody Specificity; D001665:Binding Sites; D001667:Binding, Competitive; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology; D005470:Fluorometry / Q000379:methods*; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D009374:Neoplasms, Experimental / Q000276:immunology; D013205:Staphylococcal Protein A / Q000276:immunology
chemical_list: D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D013205:Staphylococcal Protein A