Elsevier

Mucosal Immunology

Volume 5, Issue 5, September 2012, Pages 524-534
Mucosal Immunology

Article
Altered regulation of Toll-like receptor responses impairs antibacterial immunity in the allergic lung

https://doi.org/10.1038/mi.2012.28Get rights and content
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Abstract

The lung is colonized by commensal bacteria, some of which are associated with asthma exacerbations. Using the intranasal house-dust mite–sensitized mouse model of allergic airway disease, we show an imbalance in novel antibacterial pathways that culminates in a reduction in neutrophil recruitment to the airspaces and leads to bacterial invasion and dissemination. The expression of TREM (Triggering Receptor Expressed on Myeloid cells)-1 that amplifies Toll-like receptor (TLR) signaling and TREM-2 that inhibits this process is reversed. Furthermore, endogenous TLR inhibitors (A20, Tollip, SOCS1, and IRAK-M) and proteins involved in receptor recycling (TRIAD3) are raised. Consequently, the production of neutrophil chemoattractants is reduced. Intranasal administration of either chemokine restores the ability to recruit neutrophils, which prevents bacterial invasion. A background of allergic airway disease therefore exacerbates bacterial infection by altering key antibacterial innate immune pathways that are amenable to therapeutic intervention.

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Published online: 2 5 2012

SUPPLEMENTARY MATERIAL is linked to the online version of the paper

Supplementary information The online version of this article (doi:10.1038/mi.2012.28) contains supplementary material, which is available to authorized users.