title: T-cells subsets and activation in bronchial mucosa of sensitized Brown-Norway rats after single allergen exposure.
abstract: We have investigated the relationship between changes in T-cell activation in the bronchial mucosa, airway responsiveness and eosinophilic inflammation in sensitized Brown-Norway rats exposed to ovalbumin (OVA). Rats sensitized intraperitoneally with OVA and exposed to OVA aerosol 21 days later showed an enhanced increase in lung resistance (RNL) to acetylcholine (P < 0.05), and a significant increase in the number of eosinophils, neutrophils and lymphocytes in bronchoalveolar lavage fluid (BAL) (P < 0.05), compared with sensitized but saline-exposed controls. There was a significant increase in cells expressing the T-cell activation marker CD25 (P < 0.05) and the numbers of CD8+ T cells (P < 0.05), but not in the numbers of CD2+ and CD4+ cells. Eosinophil counts in airway submucosal tissue, as assessed by staining with BMK-13; a monoclonal antibody that binds to eosinophil major basic protein (MBP), were increased in rats receiving sensitization and exposure to OVA compared with naive controls (P < 0.002). There were significant positive correlations between the increase in RL to acetylcholine and the numbers of CD25+ (r = 0.92, P < 0.001), CD4+ (r = 0.77, P < 0.05), CD8+ (r = 0.71, P < 0.05) and MBP+ (r = 0.72, P < 0.03) cells in the OVA-sensitized and exposed group, but not in saline-exposed or naive animals. The number of MBP+ cells also correlated with CD25 expression (r = 0.71, P < 0.05). We conclude that airway hyper-responsiveness and inflammatory cell infiltration caused by OVA exposure of sensitized animals is associated with the presence of activated T cells in the airway mucosa. CD8+ T cells may play a role in the regulation of events leading to eosinophil inflammation and airway hyper-responsiveness.
authors.affiliation: Department of Thoracic Medicine, National Heart and Lung Institute, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Haczku
authors.forename: R
authors.initials: R
authors.lastname: Moqbel
authors.forename: M
authors.initials: M
authors.lastname: Jacobson
authors.forename: A B
authors.initials: AB
authors.lastname: Kay
authors.forename: P J
authors.initials: PJ
authors.lastname: Barnes
authors.forename: K F
authors.initials: KF
authors.lastname: Chung
mesh_terms: D000485:Allergens / Q000276:immunology*; D000818:Animals; D001980:Bronchi / Q000276:immunology*; D016535:Bronchial Hyperreactivity / Q000276:immunology; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D004804:Eosinophils / Q000276:immunology; D007124:Immunoenzyme Techniques; D007958:Leukocyte Count; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D009092:Mucous Membrane / Q000276:immunology; D010047:Ovalbumin / Q000276:immunology; D051381:Rats; D011914:Rats, Inbred BN; D016176:T-Lymphocyte Subsets / Q000276:immunology*
chemical_list: D000485:Allergens; D010047:Ovalbumin