Monomeric bovine IgG2 is a potent stimulus for bovine neutrophils.
Bovine plasma contains factors that can stimulate bovine neutrophils. Bovine plasma at 1:1,000,000-1:1,000 dilution induced a dose-dependent superoxide production in bovine neutrophils. When bovine plasma was fractionated with a protein G column, only the IgG fraction contained induction activity. At similar concentrations purified IgG induced a much stronger response than that of plasma IgG. Purified monomeric bovine IgG induced a dose-dependent increase in superoxide production. The maximum induction can be achieved at 100 micrograms/ml of bovine IgG. When subclasses of bovine IgG were examined, monomeric bovine IgG2 potently stimulated bovine polymorphonuclear leukocytes. In contrast, bovine IgG 1 failed to induce a response at similar concentrations, and neither bovine IgG F(ab')2 and Fc were effective. Both recombinant bovine granulocyte-macrophage colony-stimulating factor (r-BoGM-CSF) and recombinant bovine granulocyte colony-stimulating factor (r-BoG-CSF) primed bovine neutrophils for superoxide production induced by bovine IgG. The above results suggest that: (1) bovine plasma contain factors that can activate bovine neutrophils; (2) bovine plasma IgG is the major component that is responsible for bovine neutrophil activation; (3) bovine plasma contains factors that can inhibit the effect of bovine IgG; (4) monomeric bovine IgG2, but not IgG1, can activate bovine neutrophils directly without Fc receptor cross-linkage; (5) the integrity of bovine IgG is important in bovine polymorphonuclear leukocyte activation; and (6) bovine neutrophil activation induced by bovine IgG can be primed by r-BoGM-CSF or r-BoG-CSF.
Tao
W
W
Immunology Group, American Cyanamid Company, Princeton, New Jersey, USA.
Corbett
M J
MJ
Pickett
W
W
D000818:Animals; D002417:Cattle; D002499:Centrifugation, Density Gradient; D004305:Dose-Response Relationship, Drug; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D007140:Immunoglobulin Fab Fragments / Q000494:pharmacology; D007074:Immunoglobulin G / Q000145:classification / Q000302:isolation & purification / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology; D013481:Superoxides / Q000097:blood*
D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D013481:Superoxides; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor