Chemoattractant properties of PR-39, a neutrophil antibacterial peptide

• Published in: Journal of leukocyte biology Vol. 61; no. 5; pp. 624 - 629
• Main Authors: Huang, Hsuan‐Jen, Ross, Christopher R., Blecha, Frank
• Format: Journal Article
• Language: English
• Published: United States Society for Leukocyte Biology 01.05.1997
• Subjects: Amino Acid Sequence; Animals; Anti-Bacterial Agents - pharmacology; Antimicrobial Cationic Peptides; Calcium - metabolism; Calcium - pharmacology; calcium mobilization; Chemotactic Factors - pharmacology; chemotaxis; Chemotaxis, Leukocyte - drug effects; Molecular Sequence Data; Neutrophils - drug effects; Peptides - pharmacology; Pertussis Toxin; proline‐arginine peptide; Swine; Virulence Factors, Bordetella - pharmacology
• ISSN: 0741-5400; 1938-3673
• DOI: 10.1002/jlb.61.5.624

The proline‐arginine (PR) ‐rich antibacterial peptide, PR‐39, kills bacteria by a non‐pore‐forming mechanism. Because this neutrophil peptide possesses several distinct functional properties and because other antimicrobial peptides are chemoattractants, we sought to determine whether PR‐39 was a chemoattractant for porcine leukocytes. The peptide was synthesized by the solid‐phase method using t‐Boc chemistry and purified by reversed‐phase high‐performance liquid chromatography. Leukocyte migration was assessed with the use of a 48‐well microchemotaxis chamber. PR‐39 induced the directed migration of neutrophils. The peak chemotaxis response occurred at 0.5–2 μM, which was slightly lower than the minimal inhibitory and bactericidal concentrations for PR‐39. However, the peptide was not a chemoattractant for mononuclear cells. Truncation of PR‐39 suggested that the neutrophil chemoattractant domain may be contained within the first 26 amino acid residues. Intracellular Ca2+ fluxes in response to PR‐39 were monitored by flow cytometry and showed a transient increase that peaked at approximately 40 s and approached basal values by 4 min. However, in a Ca2+‐free environment, the PR‐39‐induced Ca2+ increase was abrogated. Furthermore, PR‐39 did not induce neutrophil chemotaxis in the absence of extracellular Ca2+, and pertussis toxin inhibited both neutrophil chemotaxis and Ca2+ mobilization. Taken together, these data suggest that PR‐39 is a Ca2+‐dependent chemoattractant of neutrophils. The finding of a neutrophil antibacterial peptide that is also a neutrophil chemoattractant is intriguing and may indicate an important role for PR‐39 in inflammation. J. Leukoc. Biol. 61: 624–629; 1997.