Stimulation of the adherence of neutrophils to umbilical vein endothelium by human recombinant tumor necrosis factor.

Recombinant human tumor necrosis factor (TNF) was found to enhance the adherence of human peripheral blood neutrophils to human umbilical vein endothelial (HUVE) cell monolayers in vitro. The enhancement was due to the effects both on neutrophils and HUVE cells. The effect on neutrophils was maximally induced within 5 min and did not require protein or RNA synthesis. By contrast, maximal effects on HUVE cells took 4 hr to develop and required de novo protein and RNA synthesis; however, exposure of HUVE cells to TNF for as little as 5 min was sufficient to initiate changes leading to maximal adherence of neutrophils at 4 hr. Both the effect on neutrophils and that on HUVE cells were blocked by a monoclonal antibody against TNF. TNF also rapidly induced an increased surface expression of neutrophil antigens recognized by monoclonal antibodies directed against epitopes of a glycoprotein required for optimum adherence and for complement component C3bi receptor (CR3) function. Thus, the mechanism of action of TNF may involve the regulation of expression of cell surface molecules. Our observations show that TNF induces a process central to the development of all inflammatory reactions and that both blood neutrophils and endothelial cells are targets of TNF action. The regulation of inflammatory reactions by TNF or antagonists of TNF has wide-ranging clinical implications.