DEMONSTRATION OF FC-GAMMA RECEPTORS ON HUMAN BASOPHIL GRANULOCYTES

  • 1 January 1979
    • journal article
    • research article
    • Vol. 123  (2) , 578-583
Abstract
Fc.gamma. receptors were detected on human basophil granulocytes. The mononuclear cell fraction of human peripheral blood was incubated with heat-aggregated human Ig[immunoglobulin]G (HGG[human .gamma.-globulin]) followed by 125I-anti-HGG. Autoradiography on the cells showed that the majority of basophil granulocytes gave a significant number of grains. Basophils were not labeled by pre-incubation of the same cells with monomeric HGG followed by 125I-anti-HGG. The binding of aggregated HGG to basophils was inhibited by the presence of a high concentration of monomeric HGG or its Fc fragment but not by the Fab fragment. Fc.gamma. receptors are probably distinct from IgE receptors on the same cells. Saturation of basophils with IgE did not affect the binding of aggregated HGG to the cells. Pre-incubation with and the presence of aggregated HGG failed to affect the binding of 125I-IgE to basophils, or to block passive sensitization of the cells with IgE antibodies. The Fc.gamma. receptors did not co-cap with IgE receptors. Aggregated HGG failed to induce histamine release from basophils even in the presence of D2O. The presence of aggregated HGG on basophils did not modulate IgE-mediated histamine release from the cells.