Endothelial Interleukin-8: A Novel Inhibitor of Leukocyte-Endothelial Interactions

Certain inflammatory stimuli render cultured human vascular endothelial cells hyperadhesive for neutrophils. This state is transient and reversible, in part because activated endothelial cells secrete a leukocyte adhesion inhibitor (LAI). LAI was identified as endothelial interleukin-8 (IL-8), the predominant species of which is an extended amino-terminal IL-8 variant. At nanomolar concentrations, purified endothelial IL-8 and recombinant human IL-8 inhibit neutrophil adhesion to cytokine-activated endothelial monolayers and protect these monolayers from neutrophil-mediated damage. These findings suggest that endothelial-derived IL-8 may function to attenuate inflammatory events at the interface between vessel wall and blood.