Role of CD8(+) T Cell in Chronic Allergic Airway Inflammation

Rha, Yeong Ho; Choi, Sun Hee

Abstract

PURPOSE: Asthma is a complex disease that is characterized by airway hyperresponsiveness (AHR), reversible airway obstruction, and inflammation, marked mainly by eosinophilic infiltration. The bulk of the evidence identifies alphaCD4(+) TH2 cells as having a pivotal role in mediating the inflammation that is central to asthma but The role of CD8(+) T cells in the development of allergic airway disease is still controversial. The purpose of this study was to investigate the role of CD8(+) T cells in the development of AHR and airway inflammation in mouse model of chronic asthma.
METHODS
Mice were sensitized to OVA by i.p. injection on day 1, 14 and then challenged by OVA intranasal instillation on days 27, 28, 29 47, 61, 73, 74 and then 75 days. Anti-CD8 antibody was administered to sensitized mice by i.v. injection 2h before second sensitization, day 27 and 73. In vivo airway responsiveness was measured by whole body plethysmography (Penh) to inhaled methacholine (MCh) on day 77. Lung eosinophilia, bronchoalveolar lavage fluid (BALF) cytokine levels were also assessed.
RESULTS
Sensitized and challenged mice showed significant airway eosinophilia and heightened AHR to methacholine when compared with non-sensitized animals. Administration of anti-CD8 antibody prevented both development of AHR as well as BALF eosinophilia. Treatment with anti-CD8 antibody also resulted in supression of IL-5 production in BALF.
CONCLUSION
These results indicate that CD8 (+) T cell may have a potential role in the development of chronic allergic airway inflammation and development of allergen-induced airway responses in mouse model.