Figure 7.

AHR in the absence of antigen sensitization and challenge occurs only in lung-specific IL-5–expressing transgenic mice. Airway responsiveness of NJ.1726 mice (A) and transgenic mice expressing IL-5 from a T cell–specific promoter (B) was measured immediately after exposure to aerosolized methacholine. In each case, measurements were made relative to age matched (3–5 mo) transgenic negative littermates. Mice were assessed on two occasions and the average for each animal was obtained. Values reported are group means ±SD (n = 11). These data were used to derive the effective dose₂₀₀ ED₂₀₀ levels (i.e., 50% maximal response) shown in the histograms to the left. The ED₂₀₀ for NJ.1726 transgenic mouse group was significantly different from the control wildtype mice (*P ⩽0.01).