Antimicrobial and immunomodulatory activities of an ovine proline/arginine-rich cathelicidin

• Published in: International journal of antimicrobial agents 2010-03, Vol.35 (3), p.288-291
• Main Authors: Yu, Pak-Lam, Cross, Martin L, Haverkamp, Richard G
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antimicrobial activity; Antimicrobial agents; Antimicrobial Cationic Peptides - immunology; Antimicrobial Cationic Peptides - isolation & purification; Antimicrobial Cationic Peptides - pharmacology; Antimicrobial peptide; atomic force microscopy; Biological and medical sciences; cathelicidins; Cationic peptides; Cell Line; Cytokine production; Cytokines; Cytology; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - immunology; Escherichia coli - ultrastructure; Immunologic Factors - genetics; Immunologic Factors - pharmacology; Immunomodulation; Infectious Disease; Inflammation; Innate immunity; Interleukin 12; Interleukin-12 - antagonists & inhibitors; Macrophages; Macrophages - drug effects; Macrophages - immunology; Medical sciences; Mice; Microscopy, Atomic Force; Murine macrophage; Ovine cathelicidins; Pathogens; Pharmacology. Drug treatments; Proline; Sheep; Staphylococcus aureus; Staphylococcus aureus - immunology
• ISSN: 0924-8579; 1872-7913
• DOI: 10.1016/j.ijantimicag.2009.10.017

Abstract In in vitro co-culture experiments, the ovine-derived cathelicidin OaBac5mini showed antimicrobial activity against Escherichia coli cells and modulated production of a cytokine by a mammalian inflammatory cell type (macrophage). Using atomic force microscopy, the morphology of peptide-treated E. coli bacteria showed no cell lysis, indicating an intracellular mode of action of the peptide leading to bacterial cell inhibition. At a concentration of 50 μg/mL OaBac5mini, the peptide suppressed production of the inflammatory cytokine interleukin-12 by murine J774A cells that had been stimulated with Staphylococcus aureus strain Cowan; levels of other cytokines were unaffected. Thus, certain cationic peptides can enter and disrupt invading Gram-negative pathogens and may be able to modulate inflammatory responses induced by Gram-positive bacterial products.