Exposure to common respiratory bacteria alters the airway epithelial response to subsequent viral infection. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Bellinghausen, Carla; Gulraiz, Fahad; Heinzmann, Alexandra; Dentener, Mieke; Savelkoul, Paul; Wouters, Emiel; Rohde, Gernot; Stassen, Frank
• Is Part Of: Respiratory research. Volume 17:Issue 1(2016)
• Page Start: 1
• Page End: 12
• Publication Date: 2016-12
• Subjects: Bacterial-viral co-infection -- Polymicrobial infection -- Inflammation; Respiratory organs -- Diseases -- Periodicals; 616.2005
• DOI: 10.1186/s12931-016-0382-z
• Languages: English
• ISSNs: 1465-993X

Abstract

Abstract Background Colonization of the airways with potential pathogenic bacteria is observed in a number of chronic respiratory diseases, such as COPD or cystic fibrosis. Infections with respiratory viruses are known triggers of exacerbations of these diseases. We here investigated if pre-exposure to bacteria alters the response of lung epithelial cells to subsequent viral infection. Methods Bronchial epithelial cells (BEAS-2B cells and primary bronchial epithelial cells) were exposed to heat-inactivatedHaemophilus influenzae, Pseudomonas aeruginosa orStreptococcus pneumoniae and subsequently infected with respiratory syncytial virus (RSV), type 2 human adenovirus or influenza B. Levels of pro-inflammatory cytokines, viral replication and expression of pattern recognition receptors were determined in culture supernatants and/or cell lysates. Results Exposure of BEAS-2B cells toH. influenzae before and during RSV-infection synergistically increased the release of IL-6 (increase above calculated additive effect at 72 h: 56 % ± 3 %, mean ± SEM) and IL-8 (53 % ± 12 %). This effect was sustained even when bacteria were washed away before viral infection and was neither associated with enhanced viral replication, nor linked to increased expression of key pattern recognition receptors.P. aeruginosa enhanced the release of inflammatory cytokines to a similar extent, yet only if bacteria were also present during viral infection.S. pneumoniae did not enhance RSV-induced cytokine release. Surprisingly, adenovirus infection significantly reduced IL-6 release in cells exposed to either of the three tested bacterial strains by on average more than 50 %. Infection with influenza B on the other hand did not affect cytokine production in BEAS-2B cells exposed to the different bacterial strains. Conclusion Pre-exposure of epithelial cells to bacteria alters the response to subsequent viral infection depending on the types of pathogen involved. These findings highlight the complexity of microbiome interactions in the airways, possibly contributing to the susceptibility to exacerbations and the natural course of airway diseases.