Figure 2: Effect of duration of CSE challenge on BAL cell recovery BALB/c mice received either PBS or 100% CSE by intranasally administration for 1, 2, 3, 4, 9 or 14 days (once daily, 5 days per week). Mice were sacrificed, the lungs lavaged and BAL macrophages (a) and neutrophils (b) counted. Each bar represents the mean ± standard deviation for 5 mice.