help button home button
AJRCCM
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH

Published ahead of print on January 17, 2008, doi:10.1164/rccm.200709-1387OC

Am. J. Respir. Crit. Care Med., Volume 177, Number 7, April 2008, 720-729

A more recent version of this article appeared on April 1, 2008
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
200709-1387OCv1
177/7/720    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Google Scholar
Right arrow Articles by Wu, Q.
Right arrow Articles by Chu, H. W.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wu, Q.
Right arrow Articles by Chu, H. W.

Submitted on September 18, 2007
Accepted on January 17, 2008

Toll-like Receptor 2 Down-regulation in Mouse Allergic Lungs Decreases Mycoplasma Clearance

Qun Wu1, Richard J Martin1, Spencer LaFasto1, Benjamin J Efaw1, John G Rino1, Ronald J Harbeck1, and Hong Wei Chu1*

1 Department of Medicine, National Jewish Medical and Research Center and the University of Colorado Health Sciences Center, Denver, CO, USA

* To whom correspondence should be addressed. E-mail: chuhw{at}njc.org.

Rationale: Respiratory Mycoplasma pneumoniae (Mp) infection is involved in asthma pathobiology, but whether the established airway allergic inflammation compromises lung innate immunity and subsequently predisposes asthmatics to Mp infection remains unknown. Objectives: To test whether the established airway allergic inflammation compromises host innate immunity [e.g., Toll-like receptor 2 (TLR2)] to hinder the elimination of Mp from the lungs. Methods: We used mouse models of ovalbumin (OVA)-induced airway allergic inflammation with an ensuing Mp infection, and cultures of mouse primary lung dendritic cells (DCs) and bone marrow-derived DCs (BMDCs). Measurements and Main Results: Lung Mp clearance in allergic mice, TLR2 and IL-6 levels in lung cells including DCs as well as in cultured primary lung DCs and BMDCs were assessed. The established OVA-induced airway allergic inflammation, or the prominent Th2 cytokines IL- 4 and IL-13, inhibited TLR2 expression and IL-6 production in lung cells including lung DCs, and eventually led to impaired host defense against Mp. Studies in IL-6 knockout mice indicated that IL-6 directly promoted Mp clearance from the lungs. IL-4 and IL-13-induced suppression of TLR2 was mediated by inhibiting nuclear factor-{kappa}B (NF-{kappa}B) activation through signal transducer and activator of transcription 6 (STAT6) signaling pathway. Conclusions: The established OVA-induced airway allergic inflammation impairs TLR2 expression and host defense cytokine (e.g., IL-6) production, and subsequently delays lung bacterial clearance. This could offer novel therapeutic strategies to reinstate TLR2 activation by using TLR2 ligands and/or blocking IL-4 and IL-13 to ameliorate persisting respiratory bacterial infections in allergic lungs.


Key words: asthma; lung; innate immunity; bacterial clearance







HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Proc. Am. Thorac. Soc. Am. J. Respir. Cell Mol. Biol.
Copyright © 2008 American Thoracic Society