Has strong antibacterial activity against P. aeruginosa. Expressed in parotid, submandibular and sublingual glands. Detected in neonatal submandibular and parotid gland secretion but not in sublingual gland secretion (at protein level). In submandibular gland, expressed at high levels in the first postnatal week, with expression diminishing thereafter. Belongs to the BPI/LBP/Plunc superfamily. Plunc family.