IMPORTANCE OF INTERLEUKIN-4 AND INTERLEUKIN-12 IN ALLERGEN-INDUCED AIRWAY CHANGES IN MICE

T helper 2 (Th2)-like cells are thought to play a crucial role in the pathogenesis of atopic asthma. In this study, we attempted to evaluate the in vivo effect of suppressing Th2 cell development on allergen-in duced airway changes. Repeated exposure of actively sensitized C57B1/6 mice to aerosolized ovalbumin (OA) causes, in comparison to saline-ex posed control animals, synthesis of specific IgE, increase of eosinoph ils in bronchoalveolar lavage fluid and airway hyperresponsiveness. Th ese effects are not observed in OA-exposed, sensitized IL-4-knockout m ice. Likewise, these effects are inhibited in OA-exposed C57B1/6 mice treated with IL-12 during initial antigen exposure. These results sugg est that suppressing Th2 cell development in vivo might have profound inhibitory effects on allergen-induced airway changes.