Previous Article | Next Article ![]()
Infect. Immun., Mar 1997, 978-985, Vol 65, No. 3
A Panyutich, J Shi, PL Boutz, C Zhao and T Ganz
Antimicrobial peptides of several structural classes have been found in
phagocytes and epithelial cells of many animals. The broadly microbicidal
protegrins (PG1, -2, and -3) were originally isolated as 16 to
18-amino-acid peptides from pig neutrophil lysates, but the corresponding
cDNA sequences encoded much larger precursors that belonged to the
cathelicidin family of antimicrobial peptides. We explored the storage,
secretion, and microbicidal activation of protegrins in porcine neutrophils
and in a model system consisting of recombinant proprotegrin 3 (pPG3) and
various serine proteases and their inhibitors. Protegrins were stored in
neutrophils as inactive proforms that were cleaved by neutrophil elastase
to mature protegrins during the preparation of granule lysate and during
phorbol myristate acetate-stimulated granule secretion from intact
neutrophils. Recombinant pPG3 was efficiently cleaved by trace amounts of
human neutrophil elastase or equivalent amounts of elastase activity from
porcine neutrophils, but pPG3 was relatively resistant to porcine
pancreatic elastase or human neutrophil cathepsin G. The recombinant pPG3
and neutrophil proprotegrins lacked microbicidal activity, but the mature
protegrins generated in the elastase-mediated cleavage reaction were as
active against Listeria monocytogenes as the chemically synthesized
protegrin. The secretion and elastase-mediated activation of proprotegrins
accounted for much of the stable microbicidal activity of porcine
neutrophil secretions against L. monocytogenes. Secreted proprotegrins and
trace amounts of elastase constitute a binary microbicidal system that is
likely to contribute to the antimicrobial activity of porcine inflammatory
fluids.
Copyright © 1997, American Society for Microbiology
Porcine polymorphonuclear leukocytes generate extracellular microbicidal activity by elastase-mediated activation of secreted proprotegrins
Department of Medicine, School of Medicine, University of California at Los Angeles, 90095, USA.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|