title: Antimicrobial and immunomodulatory activities of an ovine proline/arginine-rich cathelicidin.
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 50microg/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.
authors.affiliation: Biotechnology Group, School of Engineering and Advanced Technology, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand. P.Yu@massey.ac.nz
authors.forename: Pak-Lam
authors.initials: PL
authors.lastname: Yu
authors.forename: Martin L
authors.initials: ML
authors.lastname: Cross
authors.forename: Richard G
authors.initials: RG
authors.lastname: Haverkamp
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D004926:Escherichia coli / Q000187:drug effects / Q000276:immunology / Q000648:ultrastructure; D007155:Immunologic Factors / Q000235:genetics / Q000494:pharmacology*; D018664:Interleukin-12 / Q000037:antagonists & inhibitors; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D051379:Mice; D018625:Microscopy, Atomic Force; D012756:Sheep; D013211:Staphylococcus aureus / Q000276:immunology; D054804:Cathelicidins
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D007155:Immunologic Factors; D018664:Interleukin-12; D054804:Cathelicidins