title: Alveolar macrophages modulate allergic inflammation in a murine model of asthma.
abstract: The role of alveolar macrophages (AMs) in the pathogenesis of asthma is still unknown. The aim of the present study was to investigate the effects of AM in the murine model of asthma. AMs were selectively depleted by liposomes containing clodronate just before allergen challenges, and changes in inflammatory cells and cytokine concentrations in bronchoalveolar lavage (BAL) fluid were measured. AMs were then adoptively transferred to AM-depleted sensitized mice and changes were measured. Phenotypic changes in AMs were evaluated after in vitro allergen stimulation. AM-depletion after sensitization significantly increased the number of eosinophils and lymphocytes and the concentrations of IL-4, IL-5 and GM-CSF in BAL fluid. These changes were significantly ameliorated only by adoptive transfer of unsensitized AMs, not by sensitized AMs. In addition, in vitro allergen stimulation of AMs resulted in their gaining the ability to produce inflammatory cytokines, such as IL-1β, IL-6 and TNF-α, and losing the ability to suppress GM-CSF concentrations in BAL fluid. These findings suggested that AMs worked probably through GM-CSF-dependent mechanisms, although further confirmatory experiments are needed. Our results indicate that the role of AMs in the context of airway inflammation should be re-examined.
authors.affiliation: Department of Internal Medicine, College of Medicine, Seoul National University, Korea.
authors.forename: Bo Ram
authors.initials: BR
authors.lastname: Bang
authors.forename: Eunyoung
authors.initials: E
authors.lastname: Chun
authors.forename: Eun Jin
authors.initials: EJ
authors.lastname: Shim
authors.forename: Hyun Seung
authors.initials: HS
authors.lastname: Lee
authors.forename: Soo Yeon
authors.initials: SY
authors.lastname: Lee
authors.forename: Sang Heon
authors.initials: SH
authors.lastname: Cho
authors.forename: Kyung Up
authors.initials: KU
authors.lastname: Min
authors.forename: You Young
authors.initials: YY
authors.lastname: Kim
authors.forename: Heung Woo
authors.initials: HW
authors.lastname: Park
mesh_terms: D000818:Animals; D001249:Asthma / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D004195:Disease Models, Animal; D005260:Female; D007114:Immunization; D056747:Immunomodulation / Q000276:immunology*; D007249:Inflammation / Q000276:immunology*; D007962:Leukocytes / Q000276:immunology; D016676:Macrophages, Alveolar / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000276:immunology
chemical_list: D016207:Cytokines; D010047:Ovalbumin