The Aspergillus fumigatus inhalation model: sensitization with soluble antigens followed by allergen challenge with airborne conidia. (A) Naïve BALB/c mice (N) received neither sensitization nor allergen challenge. Mice were sensitized with immunizations of soluble Aspergillus Ag in alum and 3 intranasal inoculations with soluble Ag. The “Day 0” control group was sensitized, but not challenged. For allergen challenge, each of 5 treatment groups was exposed to resting, airborne A. fumigatus conidia for 10 min, and parameters of allergic airways disease were assessed at days 3, 7, 14, 21, and 35 after conidia. (B) Samples from the inoculation chamber were assessed under oil immersion microscopy to determine that the conidia were in the resting phase. Scale bar = 20 μm.