Staphylococcus aureus controls interleukin-5 release in upper airway inflammation

Staphylococcus aureus is a frequent colonizer of the upper airways in chronic rhinosinusitis with nasal polyps, but also resides intramucosally; it has been shown that secreted staphylococcal proteins such as enterotoxins and serine proteases induce the release of cytokines such as IL-5. We have analyzed nasal polyp tissue freshly obtained during routine surgery, which did or did not contain cultivatable S. aureus, to study spontaneous IL-5 production by nasal polyp tissue over 24 and 72 h in tissue culture. In S. aureus-positive samples we interfered by killing the bacteria using antibiotics or S. aureus specific intravenous staphylococcal phages (ISP), active or heat-inactivated. Phage-neutralizing antibodies were used to demonstrate the specificity of the phage-mediated effects. We monitored S. aureus colony forming units, and identified S. aureus proteins by mass spectrometry. We demonstrate that cultivatable S. aureus may be found in type-2 inflamed nasal polyps; the pathogen is replicating within 24 h and secretes proteins, including enterotoxins and serine proteases. The presence of S. aureus was associated with a significantly higher release of IL-5. Killing of S. aureus by antibiotics or specific ISP significantly reduced the IL-5 release. The suppressive activity of the bacteriophage on IL-5 be abolished by heat inactivation or anti-phage antibodies. Biological significance: In this study, we used high resolution mass spectrometry to identify S. aureus proteins directly in infected nasal polyp tissue and nasal polyp tissue incubated over 24 and 72 h in culture. We discovered bacterial proteins including enterotoxins and serine proteases like proteins. These experiments indicate a direct role of S. aureus in the regulation of IL-5 production in nasal polyps and may suggest the involvement of bacterial proteins detected in the tissues.