An animal model of hypersensitivity pneumonitis in rabbits. Development of chronic pulmonary inflammation and cell-mediated hypersensitivity after repeated aerosol challenge.

Chronic pulmonary inflammation was produced in immunized rabbits by repeated aerosol exposure to soluble antigen. The pulmonary inflammatory response was correlated with the development of cell-mediated hypersensitivity in the lung as evaluated by migration-inhibition studies using bronchoalveolar cells. Such inflammation could be produced with either pigeon dropping extract, an etiologic agent of hypersensitivity pneumonitis, or with human gamma globulin. Development of the inflammatory response was immunospecific and could not be transferred to normal recipients with large quantities of immune serum. Collectively, these data suggest that the development of pulmonary inflammation was due to a cell-mediated immunologic reaction in the lung.