Chronic obstructive pulmonary disease and asthma‐associated Proteobacteria, but not commensal Prevotella spp., promote Toll‐like receptor 2‐independent lung inflammation and pathology. Issue 2 (February 2015)

• Record Type: Journal Article
• Authors: Larsen, Jeppe M.; Musavian, Hanieh S.; Butt, Tariq M.; Ingvorsen, Camilla; Thysen, Anna H.; Brix, Susanne
• Is Part Of: Immunology. Volume 144:Issue 2(2015:Feb.)
• Page Start: 333
• Page End: 342
• Publication Date: 2015-02
• Subjects: Immunology -- Periodicals
• DOI: 10.1111/imm.12376
• Languages: English
• ISSNs: 0019-2805

Abstract

<abstract abstract-type="main" id="imm12376-abs-0001"> <title>Summary</title> <p>Recent studies of healthy human airways have revealed colonization by a distinct commensal bacterial microbiota containing Gram‐negative <italic>Prevotella</italic> spp. However, the immunological properties of these bacteria in the respiratory system remain unknown. Here we compare the innate respiratory immune response to three Gram‐negative commensal <italic>Prevotella</italic> strains (<italic>Prevotella melaninogenica</italic>, <italic> Prevotella nanceiensis</italic> and <italic>Prevotella salivae</italic>) and three Gram‐negative pathogenic Proteobacteria known to colonize lungs of patients with chronic obstructive pulmonary disease (COPD) and asthma (<italic>Haemophilus influenzae</italic> B, non‐typeable <italic>Haemophilus influenzae</italic> and <italic>Moraxella catarrhalis</italic>). The commensal <italic>Prevotella</italic> spp. and pathogenic Proteobacteria were found to exhibit intrinsic differences in innate inflammatory capacities on murine lung cells <italic>in vitro</italic>. <italic>In vivo</italic> in mice, non‐typeable <italic>H. influenzae</italic> induced severe Toll‐like receptor 2 (TLR2)‐independent COPD‐like inflammation characterized by predominant airway neutrophilia, expression of a neutrophilic cytokine/chemokine profile in lung tissue, and lung immunopathology. In comparison, <italic>P. nanceiensis</italic> induced a diminished neutrophilic airway inflammation and no detectable lung pathology. Interestingly, the inflammatory airway response to the Gram‐negative bacteria <italic>P. nanceiensis</italic> was completely TLR2‐dependent. These findings demonstrate weak inflammatory properties of Gram‐negative airway commensal <italic>Prevotella</italic> spp. that may make colonization by these bacteria tolerable by the respiratory immune system.</p> </abstract>