CD4 and allergic asthma: To characterize CD3+CD4+ T cells over the course of allergic asthma, we evaluated lungs and spleens of (1) healthy mice, (2) sensitized, unchallenged mice, (3) during initiation at days 3, 7, 14, and 35 after the last aerosol challenge, (4) during recovery, and (5) at relapse on days 3, 7, 14, and 35 after the last challenge using flow cytometry (Supplementary Figure 2).