GM-CSF induces human neutrophil IgA-mediated phagocytosis by an IgA Fc receptor activation mechanism.
Immunoglobulin A is the primary immunoglobulin isotype in tears, saliva, breast milk and other mucosal secretions, constituting between 6% and 15% of the total serum immunoglobulins. Human peripheral blood neutrophils have IgA receptors, but these cells do not normally participate in IgA-mediated phagocytosis. The haematopoietic factors granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) prime neutrophils to be more responsive to a variety of stimuli. We therefore studied their effect on IgA-mediated phagocytosis. GM-CSF and G-CSF both induce a change from low to high-affinity neutrophil IgA Fc crystallizable fragment receptors within 30 min; a change which is associated with the development of IgA-mediated phagocytosis. Human IL-3, which does not affect neutrophil function, is inactive in this system. These results define a new mechanism for CSF-augmented host defence whereby neutrophil function can be modulated by CSF-mediated IgA Fc receptor activation.
D002364:Caseins / Q000276:immunology; D003115:Colony-Stimulating Factors / Q000494:pharmacology*; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D006133:Growth Substances / Q000494:pharmacology*; D007070:Immunoglobulin A / Q000276:immunology*; D007700:Kinetics; D008863:Microspheres; D009504:Neutrophils / Q000276:immunology*; D009580:Nitroblue Tetrazolium; D010587:Phagocytosis; D011961:Receptors, Fc / Q000276:immunology*
D002364:Caseins; D003115:Colony-Stimulating Factors; D006133:Growth Substances; D007070:Immunoglobulin A; D011961:Receptors, Fc; D016179:Granulocyte Colony-Stimulating Factor; D009580:Nitroblue Tetrazolium; D016178:Granulocyte-Macrophage Colony-Stimulating Factor