Stimulation of human neutrophilic granulocytes by two monocyte-derived cytokines

Human monocytes upon stimulation with bacterial lipopolysaccharide release two cytokines which modulate the functions of neutrophilic granulocytes (PMN), a monocyte-derived chemotaxin (MOC) and tumor necrosis factor (TNF). Both cytokines stimulated the adherence of PMN on protein-coated nylon-fibers. Whereas MOC is one of the four most potent chemoattractants known, TNF was a most powerful inhibitor of PMN chemotactic migration towards several chemotactic factors including MOC. Neither cytokine stimulated the release of superoxide anion (O2-) or hydrogen peroxide (H2O2) from PMN in suspension. However, TNF, but not MOC, caused the release of considerable amounts of H2O2 and O2- from PMN attached to nylon fibers. The two cytokines have similar effects on the adherence, opposing effects on chemotactic migration and different effects on the oxidative burst of PMN.