Strain differences in change in airway responsiveness after repeated antigenic challenge in three strains of rats.

1. The strain differences in 2,4-dinitrophenylated-Ascaris antigen-induced airway hyperresponsiveness (AHR) were investigated in three strains of rats: Brown-Norway (BN), Long-Evans Cinnamon (LEC) and Wistar. 2. Fourty-eight hour-passive cutaneous anaphylaxis titers after repeated challenge were highest in BN and lowest in LEC. 3. Twenty-four hours after the last challenge, a marked AHR and significant increase in wet/dry weight ratio of the main bronchus were observed only in Wistar. 4. Only the isolated bronchus of the challenged Wistar among the strains showed hyperresponsiveness to acetylcholine. 5. Wistar may be the best strain for antigen-induced AHR.