Ligand binding properties of the basophilic IgE receptor of normal and allergic individuals

Abstract

The interaction of [125I]-human myeloma IgE with the human basophilic IgE receptor of normal and allergic individuals was quantitated by direct ligand binding analysis after removal of endogenous IgE. Using a mixed leukocyte preparation containing 2-5% basophils, the [125I]-IgE binding was specific for human IgE, paralleled the presence of basophils in the cell preparation, and was described by a time course similar to that reported for passive sensitization experiments. The Kd values were 4.0-13.2 nM for the normal individuals with 1.5-8.4 .times. 105 receptors per basophil, while the IgE receptor of allergic individuals was described by Kd values of 4.2-11.7 nM and 3.0-4.7 .times. 105 sites per basophil. Based upon the 11 individuals studied, the binding properties of the IgE receptor of normal and allergic individuals are apparently similar.