Fc receptor-mediated phagocytosis, superoxide production and calcium signaling of β2 integrin-deficient bovine neutrophils

Abstract

Fc receptor for immunoglobulin G-mediated phagocytosis, superoxide production and intracellular calcium ([Ca2+](i)) signaling of complement receptor type 3 (CR3)-deficient neutrophils from a heifer with leukocyte adhesion deficiency (BLAD) were compared to those of control heifers. The mean phagocytic activity of IgG-coated yeasts and aggregated bovine IgG (Agg- IgG)-induced superoxide production of CR3. deficient neutrophils were 10% and 77.9%, respectively, of those of control neutrophils. The [Ca2+](i) signals in CR3-deficient neutrophils stimulated with Agg-IgG or concanavalin A were different with mean peak [Ca2+](i) concentrations of 78% and 41.9%, respectively, of those of control neutrophils. These findings suggest that Fc receptor-mediated neutrophil functions are closely dependent on the presence of CR3 (CD11b/CD18) on the neutrophil cell surfaces.