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1260995 
Journal Article 
Abstract 
Postnatal ozone exposure enhances house dust mite induced airway hyperresponsiveness without increasing inflammation 
Gabehart, K; Correll, KA; Yang, J; Collins, ML; Loader, JE; White, CW; Dakhama, A 
2012 
Yes 
Journal of Allergy and Clinical Immunology
ISSN: 0091-6749
EISSN: 1097-6825 
129 
2 Suppl 
AB204 
WOS:000301133400766 
RATIONALE
Ozone is a common urban air pollutant. Children are particularly vulnerable to developing adverse respiratory health effects from ozone exposure. Ozone can cause tissue damage and may play a role in sensitization to allergens. We examined the effect of postnatal ozone exposure on the development of house dust mite (HDM) induced allergic airway disease in newborn mice.

METHODS
Newborn BALB/c mice (2-4 days old) were exposed to ozone (1000 ppb) or filtered air (FA) for 3 hrs followed 6 hrs later by intranasal challenge with HDM; the latter was repeated 3 times a week for 3 consecutive weeks. Lung dendritic cells (DC) were isolated 24 hrs after the first HDM challenge to examine their phenotype and accessory function. Airway responses were assessed 24hrs after the last HDM exposure. Airway inflammation was examined by measuring cytokine levels and by enumerating inflammatory cell types recovered in the BAL fluid. Airway function was assessed by invasive method, measuring changes in lung resistance in response to increasing doses of inhaled methacholine.

RESULTS
Postnatal ozone exposure did not alter lung DC phenotypes or expression of DC accessory molecules (MHC-II, CD80, CD86, and OX40L). Airway inflammation indicated by levels of IL-4, IL-5 and IL-13 in the BAL, HDM specific serum antibody levels and production of cytokines by restimulated lymphocytes was unaffected by ozone exposure. However, compared to FA, postnatal ozone significantly enhanced HDM induced airway sensitivity to methacholine.

CONCLUSIONS
Postnatal ozone increases airway sensitivity to methacholine induced by HDM allergen challenge without increasing allergic sensitization. 
2012 American Academy of Allergy, Asthma & Immunology Annual Meeting 
Orlando, FL 
March 2-6, 2012