RT Journal Article SR Electronic T1 Pseudomonas aeruginosa flagellin modulates the immune response in ex vivo lung tissue slices JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA5443 DO 10.1183/13993003.congress-2019.PA5443 VO 54 IS suppl 63 A1 Valerie Beneke A1 Nora Grahl A1 Olga Danov A1 Sebastian Konzok A1 Peter Braubach A1 Danny Jonigk A1 Gregor Warnecke A1 Olaf Pfennig A1 Hans-Gerd Fieguth A1 Armin Braun A1 Katherina Sewald A1 Susanne Häußler A1 Sabine Wronski YR 2019 UL http://erj.ersjournals.com/content/54/suppl_63/PA5443.abstract AB Chronic P. aeruginosa infections of the respiratory tract pose a major health care problem. The bacterial flagellum represents a tightly regulated virulence factor involved in biofilm formation as well as immune recognition of P. aeruginosa. Aim of this study was to delineate the role of flagellin using precision-cut lung slices (PCLS) as an organotypic, immunocompetent model of the human lung.PCLS were prepared from tumour-free lung tissue and infected with wildtype (wt) or flagellin mutant (∆fliC) PA14 strains. Persistent infection of the tissue over 24h was achieved by treatment with subinhibitory concentrations of tobramycin. Bacterial load was determined and lung tissue viability as well as specific cytokine responses were measured to assess the immune response.While the initial attachment of P. aeruginosa to the lung tissue was enhanced by the presence of the flagellum, both wt as well as ∆fliC strains were able to colonize the tissue over 24h. Analysis of cytokine profiles revealed a strong upregulation of pro-inflammatory mediators such as IL-8 (6-fold), IL-6 (6-fold), TNF-α (20-fold), GM-CSF (25-fold), IL-1β (52-fold), and MIP-3α (19-fold) after 24h of infection with wt PA14 compared to non-infected control PCLS. Importantly, infection with ∆fliC PA14 induced 2- to 4-fold lower levels of the respective molecules than the wt strain.Taken together, we show here that wt as well as flagellar mutant P. aeruginosa strains can infect human lung tissue ex vivo whereby flagellin acts as a potent immune stimulus, which could have implications for both immune evasion and biofilm formation of P. aeruginosa. Future studies will look at the transformation of acute towards persistent infection.FootnotesCite this article as: European Respiratory Journal 2019; 54: Suppl. 63, PA5443.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).