Fc receptors for IgG on human neutrophils: analysis of structure and function by using monoclonal antibody probes.
Abstract Structural and functional characteristics of Fc receptors for IgG (Fc gamma) on human neutrophils were examined with two monoclonal antibody probes specific for the Fc gamma receptors, Leu 11b and 3G8. To determine the distribution, density, and membrane mobility of the Fc gamma receptor, we used immunogold staining techniques, flow cytometry analysis, and fluorescence microscopy. Both 3G8 and Leu 11b inhibited several cell functions, thereby depicting the regulatory role of the Fc gamma receptor in mediating neutrophil activities. Among the functions studied were release of lysosomal enzymes, release of superoxide anion (O2-), and Fc-dependent rosette formation and phagocytosis. The densities of Fc gamma determinants recognized by Leu 11b and 3G8 on cells from a patient with chronic myelogenous leukemia were less than the density of epitopes on neutrophils from a normal individual. Taken together, the detailed analysis of physical and functional aspects of the Fc gamma receptor on neutrophils described in this study serve as a model for further assessment of the use of Fc gamma phenotyping of cells as a diagnostic tool.