Production of beta-defensins by human airway epithelia

Human beta-defensins (HBDs) are antimicrobial peptides that may play a role in mucosal defense. Diminished activity of these peptides has been implica ted:in the pathogenesis of cystic fibrosis (CF) lung disease. We show that HBD-1 and HBD-2 mRNAs are expressed in excised surface and submucosal gland epithelia from non-CF and CF patients, The pro-inflammatory cytokine inter leukin-1 beta stimulated the expression of HBD-2 but not HBD-1. mRNA and pe ptide in primary cultures of airway epithelia. HBD-1 was found in bronchoal veolar lavage (BAL) fluid from normal volunteers, CF patients, and patients with inflammatory lung diseases, whereas HBD-2 was detected in BAL fluid f rom patients with CF or inflammatory lung diseases, but not in normal volun teers. Both HBD-1 and HBD-2 were found in BAL fluid in concentrations of se veral ng/ml, and both recombinant peptides showed salt-sensitive bactericid al activity. These data suggest that in the lung HBD-2 expression is induce d by inflammation, whereas HBD-1 may serve as a defense in the absence of i nflammation.