Abstract: AIM: To observe the effects of aerosol imiquimod on the antigen-induced airway inflammation and Foxp3⁺ regulatory T cells.METHODS: Thirty-two female BALB/c mice were randomly divided into four groups: control, asthma model, imiquimod and glucocorticoid treatment groups. Asthma was induced by OVA administration in the asthma model, imiquimod and glucocorticoid treatment groups. Imiquimod and dexamethasone were administered to immunized mice before antigen challenge. After 48 hrs of the last challenge, the mice were killed and bronchial alveolar lavage fluid (BALF) was collected to count the number of eosinophil and to measure the levels of IL-5 and IL-10. The lung tissues of inferior lobe of the left lung were obtained for the observation of lung pathological change. The spleen CD₄⁺T cells were isolated and collected. The proportion of CD₂₅⁺Foxp3⁺T cells in the CD₄⁺T cells were determined with flow cytometry.RESULTS: (1)Imiquimod attenuated the airway inflammation of asthmatic mice. (2)In imiquimod and dexamethasone treatment groups eosinophil counts increased by OVA was decreased in BALF of mice. (3)In BALF of imiquimod treatment mice, the level of IL-5 increased by OVA was decreased and IL-10 decreased by OVA was increased.(4)The number and proportion of CD₄⁺CD₂₅⁺ Foxp3⁺T cells were higher in control and treatment groups than that in the asthmatic group.CONCLUSION: Imiquimod aerosol inhalation may inhibit antigen-induced airway inflammation and the number and proportion of CD₄⁺CD₂₅⁺Foxp3⁺T cells.

Key words: Asthma, Imiquimod, Regulatory T cells  ,  ,  ,  ,