Involvement of the platelet-activating factor receptor in host defense against Streptococcus pneumoniae during postinfluenza pneumonia.

Abstract

Although influenza infection alone may lead to pneumonia, secondary bacterial infections are a much more common cause of pneumonia. Streptococcus pneumoniae is the most frequently isolated causative pathogen during postinfluenza pneumonia. Considering that S. pneumoniae utilizes the platelet-activating factor receptor (PAFR) to invade the respiratory epithelium and that the PAFR is upregulated during viral infection, we here used PAFR gene-deficient (PAFR-/-) mice to determine the role of this receptor during postinfluenza pneumococcal pneumonia. Viral clearance was similar in wild-type and PAFR-/- mice, and influenza virus was completely removed from the lungs at the time mice were inoculated with S. pneumoniae (day 14 after influenza infection). PAFR-/- mice displayed a significantly reduced bacterial outgrowth in their lungs, a diminished dissemination of the infection, and a prolonged survival. Pulmonary levels of IL-10 and KC were significantly lower in PAFR-/- mice, whereas IL-6 and TNF-alpha were only trendwise lower. These data indicate that the pneumococcus uses the PAFR leading to severe pneumonia in a host previously exposed to influenza A.

• Authors: Koenraad F van der Sluijs, Leontine J R van Elden, Monique Nijhuis, Rob Schuurman, Sandrine Florquin, Takao Shimizu, Satoshi Ishii, Henk M Jansen, René Lutter, Tom van der Poll
• Journal: American journal of physiology. Lung cellular and molecular physiology (Am J Physiol Lung Cell Mol Physiol) Vol. 290 Issue 1 Pg. L194-9 (Jan 2006) ISSN: 1040-0605 [Print] United States
• PMID: 16100290 (Publication Type: Journal Article)

Chemical References

• Chemokines
• Cytokines
• Platelet Membrane Glycoproteins
• Receptors, G-Protein-Coupled
• platelet activating factor receptor

Topics

• Animals
• Bronchoalveolar Lavage Fluid (cytology)
• Chemokines (metabolism)
• Cytokines (metabolism)
• Female
• Immunity
• Influenza A virus
• Lung (metabolism)
• Mice
• Mice, Inbred C57BL
• Mice, Knockout
• Orthomyxoviridae Infections (complications)
• Osmolar Concentration
• Platelet Membrane Glycoproteins (metabolism)
• Pneumonia (etiology, immunology)
• Pneumonia, Pneumococcal (immunology, metabolism, pathology, physiopathology)
• Receptors, G-Protein-Coupled (metabolism)
• Streptococcus pneumoniae (growth & development, immunology)
• Survival Analysis