Proteases from salmon stimulate IL-8 in airway epithelial cells

In this study the ability of salmon tissue extracts to stimulate interleukin 8 (IL-8) production in airway epithelial cells (A549) was investigated; in particular, the role of serine protease enzymes and endotoxin was examined with respect to IL-8-stimulating ability. A549 cells were stimulated by various concentrations of fish tissue extracts for 6 h. Parallel samples were incubated with a protease inhibitor cocktail, a serine protease inhibitor, or an endotoxin inhibitor. The amount of secreted IL-8 in the supernatant was determined by an enzyme-linked immunosorbent assay. A549 cells showed a concentration-dependent increase in IL-8 secretion after stimulation with extracts of salmon tissues. The IL-8-stimulating effect was inhibited by serine protease inhibitors but not by endotoxin inhibitors.