ABSTRACT
AIM: To investigate the effect of human polymorphonuclear leukocytes (PMNs) on the release of TNF-? by the human peripheral blood mononuclear cells (PBMCs) and to elucidate its mechanism. METHODS: Human PMNs and PBMCs were isolated from the venous blood of healthy donors by dextran sedimentation and density gradient centrifugation. After the cells were cocultured at the ratio of 2:1 in the presence of lipopolysaccharide (LPS), the concentration of TNF-? in the supernatant was measured by enzyme-linked immunosorbent assay. The binding rate of monocytes with the fluorescein isothiocyanate-labeled LPS (FITC-LPS) and the mean surface fluorescence intensity of monocytes were analyzed by flow cytometry. RESULTS: PMNs do not produce detectable TNF-? in the presence of LPS. PMNs were capable of inhibiting the TNF-? release from PBMCs ( P