T cells and neutrophils exhibit differential adhesion to cytokine-stimulated endothelial cells.

In vitro adhesion assays were used to directly compare the adhesion of polymorphonuclear leucocytes (PMN) and T cells to endothelial cells (EC). PMN exhibited lower binding to unstimulated EC than T cells. When EC were stimulated with interleukin-1 (IL-1), tumour necrosis factor (TNF) or bacterial lipopolysaccharide (LPS) there was a large and rapid increase in adhesiveness for PMN which peaked at 4 hr. This had fallen significantly by 24 hr and by 72 hr was not significantly elevated above unstimulated adhesion. The increase in adhesiveness of cytokine-stimulated EC for T cells was smaller and more gradual than for PMN, with adhesion peaking around 8 hr and remaining significantly elevated at 72 hr. In contrast, interferon-gamma (IFN-gamma) enhanced EC adhesiveness for T cells but not for PMN, with maximal T cell EC adhesiveness occurring 24 hr after stimulation. As leucocyte adhesion to vascular endothelium is the first step in diapedesis, differences in PMN and T-cell adhesion to EC may be important in determining the timing and composition of inflammatory infiltrates.