Animal model of sensitization by inhalation.

Groups of rats exposed to daily inhalation challenge with aerosolized pigeon serum developed precipitating antibody within 2 weeks and definitive granulomatous inflammatory changes in the lung after 7 weeks of exposure. The dissociation of the two responses to an inhalation challenge indicate that the rat model may serve for screening of the various inhalant antigens for their sensitizing potential, and for investigation of the contributory role of some of the factors involved in the pathogenesis of hypersensitivity pneumonitis.