SURFACE MARKERS OF HUMAN EOSINOPHILS

Abstract

Peripheral blood eosinophils from patients with eosinophilia and from healthy subjects were studied for surface immunoglobulins [Ig], receptors for the Fc region of IgG, complement [C] receptors, and spontaneous rosette formation with sheep and mouse erythrocytes. Eosinophils had receptors for C, aggregated IgG, and the same 2 types of C receptors as do lymphocytes and monocytes. Immune adherence type receptors were specific for C4 [the 4th C component] or C3b [b fragment of C3] while C3d receptors were specific for C3d but unreactive with C4. Eosinophils differed from fully mature neutrophils in that the former had C3d receptors and relatively weak immune adherence (C4 or C3b) receptors, while the latter did not have the C3d receptors and had strong immune adherence receptors. Eosinophil phagocytosis of C-receptor bound erythrocytes was dependent on the presence of IgG in the antibody coating the red blood cells; this requirement for IgG resembled that found in neutrophil phagocytosis. No surface Ig or spontaneous erythrocyte rosette formation was observed with eosinophils.