Fig. 2.

Airway hyperresponsiveness upon a secondary OVA challenge is persistent when mice were rechallenged 5 or 7 weeks after the initial inhalation challenge. However, airway hyperresponsiveness disappeared when mice were rechallenged 9 or 12 weeks after the initial challenge. The results are presented as PC₂₀₀ values, where PC₂₀₀ is the concentration of methacholine required to increase the baseline Penh by 200%.