ALLERGEN-SPECIFIC IGE AND IL-5 ARE ESSENTIAL FOR THE DEVELOPMENT OF AIRWAY HYPERRESPONSIVENESS

The mechanisms underlying the development of airway hyperresponsivenes s are not fully delineated. We addressed this question by studying the effects of passive sensitization with anti-OVA IgE on the development of altered airway responsiveness (AR) following local challenge with OVA in normal and athymic mice. Both normal and athymic BALB/c mice de veloped allergen-specific immediate cutaneous hypersensitivity after p assive sensitization with anti-OVA IgE. In contrast, the combination o f local challenge with allergen via the airways and passive sensitizat ion triggered the development of airway hyperresponsiveness only in no rmal but not in athymic mice. Treatment of athymic mice with IL-5 sign ificantly increased eosinophil accumulation in the lungs after local c hallenge with OVA; increased airway reactivity was only observed in at hymic mice which received anti-OVA IgE, not an unrelated IgE, plus IL- 5 treatment and airway challenge with OVA. These findings identify the requirement for allergen-specific IgE and IL-5 for the development of airway hyperresponsiveness following allergen challenge via the airwa ys.