Influence of antibody and complement components on phagocytosis and chemiluminescence of macrophages.
Macrophages are known to release reactive oxygen species (O2-, 1O2, H2O2, OH.) in response to various membrane stimuli. However, our studies show that phagocytic stimulation of macrophages is not necessarily accompanied by a stimulation of the oxidative burst. Whereas IgG-opsonized erythrocytes were capable to induce phagocytosis and a chemiluminescence response, both being dependent on the number of IgG bound per erythrocyte, C3b-bearing erythrocytes were well ingested but failed to induce any chemiluminescence reaction. Furthermore, stimulation of macrophages, via the Fc-receptors, seems to alter their functional state in regard to the activation of a receptor, which enables them to recognize membrane lesions on the target erythrocyte. The presence of IgG and membrane lesions, e.g. the C5b-9-complex of complement, induced a marked increase in chemiluminescence compared with stimulation by IgG-bearing particles alone. The augmented response of macrophages was at least in part due to an additional release of H2O2, which was not liberated in response to IgG-bearing erythrocytes. This "lesion recognizing receptor" in the macrophage membrane could not be activated by stimulation of C3b-receptors, indicating its functional linkage to the Fc-receptors.
D000818:Animals; D000918:Antibody Specificity; D002374:Catalase / Q000494:pharmacology; D003182:Complement C5 / Q000276:immunology*; D003186:Complement C9 / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology; D008163:Luminescent Measurements; D008165:Luminol; D008264:Macrophages / Q000276:immunology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009895:Opsonin Proteins; D010587:Phagocytosis; D011951:Receptors, Complement / Q000276:immunology; D017463:Receptors, Complement 3b; D011961:Receptors, Fc / Q000276:immunology; D013482:Superoxide Dismutase / Q000494:pharmacology
D003182:Complement C5; D003186:Complement C9; D007074:Immunoglobulin G; D009895:Opsonin Proteins; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D011961:Receptors, Fc; D008165:Luminol; D002374:Catalase; D013482:Superoxide Dismutase