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School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, United Kingdom,1 School of Dentistry, University of Birmingham, St. Chad's Queensway, Birmingham B4 6NN, United Kingdom2
Received 1 May 2007/ Returned for modification 16 July 2007/ Accepted 31 October 2007
Porphyromonas gingivalis, a gram-negative anaerobe which is implicated in the etiology of active periodontitis, secretes degradative enzymes (gingipains) and sheds proinflammatory mediators (e.g., lipopolysaccharides [LPS]). LPS triggers the secretion of interleukin-8 (IL-8) from immune (72-amino-acid [aa] variant [IL-872aa]) and nonimmune (IL-877aa) cells. IL-877aa has low chemotactic and respiratory burst-inducing activity but is susceptible to cleavage by gingipains. This study shows that both R- and K-gingipain treatments of IL-877aa significantly enhance burst activation by fMLP and chemotactic activity (P < 0.05) but decrease burst activation and chemotactic activity of IL-872aa toward neutrophil-like HL60 cells and primary neutrophils (P < 0.05). Using tandem mass spectrometry, we have demonstrated that R-gingipain cleaves 5- and 11-aa peptides from the N-terminal portion of IL-877aa and the resultant peptides are biologically active, while K-gingipain removes an 8-aa N-terminal peptide yielding a 69-aa isoform of IL-8 that shows enhanced biological activity. During periodontitis, secreted gingipains may differentially affect neutrophil chemotaxis and activation in response to IL-8 according to the cellular source of the chemokine.
Published ahead of print on 19 November 2007.
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
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| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
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