Toll-like receptor 2–expressing macrophages are required and sufficient for rhinovirus-induced airway inflammation

Mingyuan Han, Yutein Chung, Jun Young Hong, Charu Rajput, Jing Lei, Joanna L. Hinde, Qiang Chen, Steven P. Weng, J. Kelley Bentley, Marc B. Hershenson

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

Background We have shown that rhinovirus, a cause of asthma exacerbation, colocalizes with CD68+ and CD11b+ airway macrophages after experimental infection in human subjects. We have also shown that rhinovirus-induced cytokine expression is abolished in Toll-like receptor (TLR2)−/− bone marrow–derived macrophages. Objective We hypothesize that TLR2+ macrophages are required and sufficient for rhinovirus-induced airway inflammation in vivo. Methods Naive and ovalbumin (OVA)–sensitized and challenged C57BL/6 wild-type and TLR2−/− mice were infected with RV1B, followed by IgG or anti-TLR2, to determine the requirement and sufficiency of TLR2 for rhinovirus-induced airway responses. Bone marrow chimera experiments using OVA-treated C57BL/6 and TLR2−/− mice were also performed. Finally, naive TLR2−/− mice underwent intranasal transfer of bone marrow–derived wild-type macrophages. Results RV1B infection of naive wild-type mice induced an influx of airway neutrophils and CD11b+ exudative macrophages, which was reduced in TLR2−/− mice. After allergen exposure, rhinovirus-induced neutrophilic and eosinophilic airway inflammation and hyperresponsiveness were reduced in TLR2−/− and anti-TLR2–treated mice. Transfer of TLR2−/− bone marrow into wild-type, OVA-treated C57BL/6 mice blocked rhinovirus-induced airway responses, whereas transfer of wild-type marrow to TLR2−/− mice restored them. Finally, transfer of wild-type macrophages to naive TLR2−/− mice was sufficient for neutrophilic inflammation after rhinovirus infection, whereas macrophages treated with IL-4 (to induce M2 polarization) were sufficient for eosinophilic inflammation, mucous metaplasia, and airways hyperresponsiveness. Conclusions TLR2 is required for early inflammatory responses induced by rhinovirus, and TLR2+ macrophages are sufficient to confer airway inflammation to TLR2−/− mice, with the pattern of inflammation depending on the macrophage activation state.

Original languageEnglish
Pages (from-to)1619-1630
Number of pages12
JournalJournal of Allergy and Clinical Immunology
Volume138
Issue number6
DOIs
Publication statusPublished - 2016 Dec 1

Bibliographical note

Publisher Copyright:
© 2016 American Academy of Allergy, Asthma & Immunology

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology

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