SLPI is a secreted inhibitor which guards epithelial tissues from serine proteases. SLPI is localized in various secretions including seminal plasma, cervical mucus, and bronchial secretions, and has affinity for trypsin, leukocyte elastase, and cathepsin G. SLPI inhibitory effect contributes to the immune response by protecting epithelial surfaces from attack by endogenous proteolytic enzymes. SLPI protein has broad-spectrum anti-biotic activity. SLPI is an acid-stable proteinase inhibitor with strong affinities for trypsin, chymotrypsin, elastase, and cathepsin G. SLPI prevents elastase-mediated damage to oral and mucosal tissues.
