title: Effect of ozone exposure on allergic sensitization and airway inflammation induced by dendritic cells.
abstract: BACKGROUND
  Epidemiological studies suggest that ozone exposure is related to increased asthma symptoms. Dendritic cells (DCs) are the principal antigen-presenting cells in the airways.
  
  
  OBJECTIVE
  We have examined whether ambient doses of ozone (100 ppb for 2 h) enhance allergic sensitization and/or airway inflammation in a mouse model.
  
  
  METHODS
  C57BL/6 mice were sensitized to inhaled ovalbumin (OVA) by intratracheal instillation of OVA-pulsed DCs on day 0. Daily exposure to OVA aerosol on days 14-20 resulted in an eosinophilic airway inflammation, as reflected in bronchoalveolar lavage fluid and lung histology. In a first experiment, mice were exposed to ozone or room air immediately prior to and following sensitization. Subsequently, we tested the effect of ozone exposure during antigen challenge in DC-sensitized mice.
  
  
  RESULTS
  Exposure to ozone during sensitization did not influence airway inflammation after subsequent allergen challenge. In contrast, in sensitized mice, challenge with OVA together with ozone (days 14-20) resulted in enhanced airway eosinophilia and lymphocytosis, as compared with mice exposed to OVA and room air (1.91 x 106 +/- 0.46 x 106 vs. 0.16 x 106 +/- 0.06 x 106 eosinophils/mL lavage fluid; P = 0.015; 0.49 x 106 +/- 0.11 x 106 vs. 0.08 x 106 +/- 0.03 x 106 lymphocytes/mL lavage fluid; P = 0.004). Ozone exposure without subsequent OVA exposure did not cause airway inflammation.
  
  
  CONCLUSIONS
  Ozone exposure does not increase allergic sensitization but enhances antigen-induced airway inflammation in mice that are sensitized via the airways.
authors.affiliation: Department of Respiratory Diseases, Ghent University Hospital, Ghent, Belgium. guy.joos@rug.ac.be
authors.forename: P O
authors.initials: PO
authors.lastname: Depuydt
authors.forename: B N
authors.initials: BN
authors.lastname: Lambrecht
authors.forename: G F
authors.initials: GF
authors.lastname: Joos
authors.forename: R A
authors.initials: RA
authors.lastname: Pauwels
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects* / Q000276:immunology*; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D002465:Cell Movement; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D004195:Disease Models, Animal; D004306:Dose-Response Relationship, Immunologic; D007114:Immunization; D007249:Inflammation / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D008168:Lung / Q000098:blood supply* / Q000166:cytology / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000009:adverse effects / Q000276:immunology; D010083:Oxidants, Photochemical / Q000009:adverse effects*; D010126:Ozone / Q000009:adverse effects* / Q000276:immunology*; D012130:Respiratory Hypersensitivity / Q000209:etiology / Q000276:immunology / Q000473:pathology
chemical_list: D000393:Air Pollutants; D010083:Oxidants, Photochemical; D010126:Ozone; D010047:Ovalbumin