title: Rhinovirus infection induces interleukin-13 production from CD11b-positive, M2-polarized exudative macrophages.
abstract: Rhinovirus (RV) causes asthma exacerbations. Previously, we showed that adherent bronchoalveolar cells from allergen-treated mice produce IL-13 when stimulated with RV ex vivo, implicating cells of the monocyte/macrophage lineage in viral-induced airway inflammation. In this study, we hypothesized that RV infection of allergen-treated mice results in IL-13 production by CD11b+ exudative macrophages in vivo. We sensitized and challenged BALB/c mice with ovalbumin (OVA), after which mice were inoculated with RV or sham HeLa cell lysate. After 1 day, lungs were harvested, and cell suspensions were analyzed by flow cytometry. We repeated this process in IL-13 reporter mice, CD11b-DTR mice in which diphtheria toxin selectively depletes CD11b+ cells, and chemokine receptor 2 (CCR2) null mice. We found that lungs of mice infected with RV alone showed increases in CD45+, CD68+, F4/80+, Ly6C+, and CD11b(high) cells, indicating an influx of inflammatory monocytes and exudative macrophages. The combination of OVA and RV had synergistic effects on the exudative macrophage number. However, CD11b+ cells from OVA-treated, RV-infected mice showed M2 polarization, including expression of CD206 and CD301 and production of IL-13. Similar results were obtained in IL-13 reporter mice. Diphtheria toxin depleted CD11b+, IL-13-producing cells in OVA-treated, RV-infected, CD11b-DTR mice, decreasing airway inflammation and responsiveness. CD11b+, Ly6C+ cells were reduced in CCR2 knockout mice. We conclude that, in contrast to naive mice, RV infection of mice with allergic airways disease induces an influx of IL-13-producing CD11b+ exudative macrophages bearing M2 macrophage markers. This finding further implicates alternatively activated macrophages in RV-induced asthma exacerbations.
authors.affiliation: Departments of 1 Pediatrics and Communicable Diseases and.
authors.forename: Yutein
authors.initials: Y
authors.lastname: Chung
authors.forename: Jun Young
authors.initials: JY
authors.lastname: Hong
authors.forename: Jing
authors.initials: J
authors.lastname: Lei
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chen
authors.forename: J Kelley
authors.initials: JK
authors.lastname: Bentley
authors.forename: Marc B
authors.initials: MB
authors.lastname: Hershenson
mesh_terms: D000485:Allergens / Q000276:immunology; D000818:Animals; D001249:Asthma / Q000276:immunology / Q000378:metabolism / Q000821:virology*; D039481:CD11b Antigen / Q000276:immunology*; D016764:Cell Polarity; D004195:Disease Models, Animal; D005260:Female; D007249:Inflammation / Q000276:immunology; D018793:Interleukin-13 / Q000096:biosynthesis*; D008168:Lung / Q000276:immunology / Q000378:metabolism / Q000821:virology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000276:immunology*; D012229:Rhinovirus
chemical_list: D000485:Allergens; D039481:CD11b Antigen; D018793:Interleukin-13; D010047:Ovalbumin
keywords: alternative activation; asthma; exacerbation; innate immunity