The Toll-like receptor 5 ligand flagellin promotes asthma by priming allergic responses to indoor allergens.

Published

Journal Article

Allergic asthma is a complex disease characterized by eosinophilic pulmonary inflammation, mucus production and reversible airway obstruction. Exposure to indoor allergens is a risk factor for asthma, but this disease is also associated with high household levels of total and particularly Gram-negative bacteria. The ability of bacterial products to act as adjuvants suggests they might promote asthma by priming allergic sensitization to inhaled allergens. In support of this idea, house dust extracts (HDEs) can activate antigen-presenting dendritic cells (DCs) in vitro and promote allergic sensitization to inhaled innocuous proteins in vivo. It is unknown which microbial products provide most of the adjuvant activity in HDEs. A screen for adjuvant activity of microbial products revealed that the bacterial protein flagellin (FLA) stimulated strong allergic airway responses to an innocuous inhaled protein, ovalbumin (OVA). Moreover, Toll-like receptor 5 (TLR5), the mammalian receptor for FLA, was required for priming strong allergic responses to natural indoor allergens present in HDEs. In addition, individuals with asthma have higher serum levels of FLA-specific antibodies as compared to nonasthmatic individuals. Together, these findings suggest that household FLA promotes the development of allergic asthma by TLR5-dependent priming of allergic responses to indoor allergens.

Full Text

Cited Authors

  • Wilson, RH; Maruoka, S; Whitehead, GS; Foley, JF; Flake, GP; Sever, ML; Zeldin, DC; Kraft, M; Garantziotis, S; Nakano, H; Cook, DN

Published Date

  • November 2012

Published In

Volume / Issue

  • 18 / 11

Start / End Page

  • 1705 - 1710

PubMed ID

  • 23064463

Pubmed Central ID

  • 23064463

Electronic International Standard Serial Number (EISSN)

  • 1546-170X

International Standard Serial Number (ISSN)

  • 1078-8956

Digital Object Identifier (DOI)

  • 10.1038/nm.2920

Language

  • eng