Measurement of Fc gamma receptor-mediated binding and phagocytosis

This unit describes functional assays that quantify macrophage FcgammaR surface expression. In each assay, IgG-opsonized sheep red blood cells (SRBC) labeled with Na2 51CrO4 are used to detect interaction with macrophages. The Basic Protocol measures phagocytosis of target cells following treatment of macrophages with agents known to modulate FcgammaR expression. The Alternate Protocol describes a method that can be used to measure FcgammaR-mediated binding of target cells to macrophages. A choice of opsonin in both methods allows for some discrimination between subclasses of FcgammaRs that are responsible for the observed results.