IL-5-producing T cells that induce airway eosinophilia and hyperresponsiveness are suppressed by dexamethasone and cyclosporin A in mice.

We have recently demonstrated that airway eosinophilic inflammation can be transferred to unprimed mice by infusion of IL-5-producing T cell clones. In this study, we investigated the effects of dexamethasone and cyclosporin A on the airway eosinophilic inflammation in mice transferred with T cell clones. An ovalbumin-reactive T cell clone, KW29, produced IL-5 as well as IL-2 and IL-4 upon stimulation with relevant antigen. Dexamethasone and cyclosporin A dose-dependently suppressed the production of these cytokines in vitro. The number of eosinophils recovered in the bronchoalveolar lavage fluid and the airway responsiveness to acetylcholine were increased in KW29-transferred mice after antigen provocation. Both responses were dose-dependently suppressed by the administration of dexamethasone or cyclosporin A in vivo. We concluded that airway eosinophilic inflammation can be controlled by agents capable of downregulating IL-5 production in T cells.