Leukocyte-derived antimicrobial proteins.

Survival in environments teeming with microbes depends on efficient mechanisms of host defense. Antimicrobial peptides and polypeptides in granules of leukocytes (eg, neutrophils) provide an important arm of first-line defense against invading microorganisms. Recent studies have broadened the scope and settings in which these proteins may function and, in at least one case, are leading to the development of a recombinant product that may provide a novel therapy for bacterial diseases when endogenous defenses are limiting.