Interleukin-10 does not mediate inhalational tolerance in a chronic model of ovalbumin-induced allergic airway disease

Objective: IL-10 is a potent anti-inflammatory cytokine, and IL-10-producing regulatory T cells are effective inhibitors of murine asthmatic responses. This study determined whether IL-10-dependent mechanisms mediated the local inhalational tolerance seen with chronic inhalational exposure to antigen. Methods: Wildtype and IL-10(-/-) mice were sensitized with ovalbumin (OVA) and then challenged with daily OVA inhalations for 10 days or 6 weeks. Results: The 10-day animals developed allergic airway disease, characterized by BAL eosinophilia, histologic airway inflammation and mucus secretion, methacholine hyperresponsiveness. and OVA-specific IgE production. These changes were more pronounced in IL10(-/-) mice. The 6-week IL-10(-/-) and wildtype animals both developed inhalational tolerance. with resolution of airway inflammation but persistence of OVA-specific IgE production. Conclusion: IL-10 may have anti-inflammatory effects in the acute stage of murine allergic airways disease. but the cytokine does not mediate the development of local inhalational tolerance with chronic antigen exposure. (c) 2006 Elsevier Inc. All rights reserved.