Effects of neutrophil adherence on the characteristics of receptors for tumor necrosis factor-alpha.

Human recombinant [125I]TNF-alpha was incubated with non-adherent human neutrophils, cells adherent to fibronectin-coated plastic, or adherent cells scraped into suspension (post-adherent). Binding of TNF to all cells increased with doses of added TNF but adherent cells bound little TNF. Binding of TNF by post-adherent cells was greater than when adherent, but still significantly less than that of non-adhered neutrophils, suggesting that TNF receptors were relocated on the adherent surface of neutrophils. Scatchard analysis showed that adherent cells expressed significantly fewer TNF receptors, but of higher affinity, than non-adherent cells. The results suggest that altered expression of TNF receptors might contribute to the differential effects of TNF on adherent and non-adherent neutrophils.