Lactoperoxidase and human airway host defense.

The lactoperoxidase (LPO) antibiotic system is a well-characterized component of mammary and salivary gland secretions. Because LPO has been shown to function in ovine airways, human airway tissue and secretions were examined for the presence of LPO and its substrate, the anion thiocyanate (SCN-). In addition, human airway secretions were tested for LPO-mediated antibacterial activity, and LPO's activity was assessed against some human airway pathogens.