Comparison of Fc gamma-receptors isolated from normal human serum and peripheral blood lymphocytes.

In this study, Fc gamma-receptors were isolated from normal human peripheral blood lymphocytes by prolonged incubation at 37 degrees C and purified by affinity chromatography using Sepharose 4B combined with heat-aggregated IgG. These labile Fc gamma R-receptors were shown to be functionally active with an apparent molecular weight of 60 K. Serum Fc gamma-receptor like molecules were also isolated and were shown to be of similar molecular weight. In addition, a high molecular weight (greater than 19S) serum IgG-binding protein was found. The basic sub-unit structure of this molecule was also 60K suggesting that the Fc gamma-receptor may exist in a polymeric or complexed form in normal human serum.