Effect of OVA or PBS aerosol challenge on the number of DCs in the large conducting airways.

Mice were immunized with OVA-DCs or PBS-DCs and challenged daily with either OVA or PBS aerosol. Thereafter, whole mounts were prepared and stained with an Ab directed against I-A and I-E MHCII. (A) In PBS-DC/PBS-exposed animals nearly all MHCII⁺ cells demonstrate a dendritic morphology. (B) In contrast, in OVA-DC/OVA mice the MHCII⁺ cells are more numerous, and have a rounded appearance. They are distributed in dense clusters in the intercartilaginous area. Original magnification, × 400, Normaski optics.