concanavalin-a and Leukocyte-Adhesion-Deficiency-Syndrome

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.

Topics: Animals; Calcium; Cattle; Cattle Diseases; CD18 Antigens; Concanavalin A; Cytochrome c Group; Female; Immunoglobulin G; Leukocyte-Adhesion Deficiency Syndrome; Neutrophils; Phagocytosis; Receptors, IgG; Second Messenger Systems; Superoxides

The expression of Fc receptors for immunoglobulin G(IgG) and concanavalin A (con A)-binding receptors, luminol-dependent chemiluminescent (LDCL) responses, and the effect of anti-bovine IgG on LDCL responses were evaluated in neutrophils from Holstein calves with leukocyte adhesion deficiency (BLAD). Neutrophils from affected calves showed a 2.1- to 2.5-fold increase in Fc receptor expression compared with those of control calves by flow cytometric analysis. Con A-binding activities of neutrophils from affected calves were similar to those of control calves. Neutrophils from a calf with BLAD, when stimulated with zymosan opsonized with bovine serum (OPZ), heat-aggregated bovine IgG (Agg-bovine IgG), sheep red blood cells (SRBC) sensitized with anti-SRBC antibody (SRBC-anti-SRBC Ab), or con A had LDCL responses of 36 (P < 0.05), 77, 126 and 119% of peak LDCL values of controls, respectively. The NBT-reducing value of neutrophils from a calf with BLAD when stimulated with Agg-bovine IgG after pretreatment with anti-bovine IgG was 116.5% of the values of neutrophils from control calves, but the difference was not significant. The LDCL responses of neutrophils from a control calf and a calf with BLAD stimulated with OPZ were inhibited markedly by pre-incubation with anti-bovine IgG antiserum at concentrations ranging from 1.25 to 20 or 40 micrograms/ml. Although an increase in Fc receptor expression on neutrophils from calves with BLAD was observed, the LDCL responses stimulated with SRBC-anti-SRBC Ab and NBT-reducing activity stimulated with Agg-bovine IgG after pretreatment with anti-bovine IgG did not correlate significantly with the increased Fc receptor expression. These results support that neutrophil functions mediated by the Fc receptors are associated synergistically with the presence of the complement receptor type 3 (CR3)(CD11b/CD18).

Topics: Animals; Cattle; Cattle Diseases; Concanavalin A; Female; Flow Cytometry; Immunoglobulin G; Indicators and Reagents; Leukocyte-Adhesion Deficiency Syndrome; Luminescent Measurements; Luminol; Neutrophils; Nitroblue Tetrazolium; Opsonin Proteins; Receptors, Complement 3b; Receptors, Concanavalin A; Receptors, Fc