An Animal Model of Hypersensitivity Pneumonitis in the Rabbit. Induction of Cellular Hypersensitivity to Inhaled Antigens Using Carrageenan and BCG
American Review of Respiratory Disease, Vol. 116, No. 6 (December 1977): 1007-1012. Permalink.
Previous studies from our laboratory have indicated that long-term aerosol exposure to pigeon dropping extract, one of the etiologic agents of hypersensitivity pneumonitis, did not produce lung lesions (1). However, inflaming the lungs with dead bacillus Calmette-Guérin and continued inhalation of pigeon dropping extract induced cell-mediated hypersensitivity to inhaled antigens in bronchoalveolar cells. On the basis of these data, we suggested that some inflammatory agent that affected the lung could result in the induction of cell-mediated hypersensitivity to inhaled antigens in human hypersensitivity pneumonitis. Data in the present study showed that carrageenan, another inflammatory agent, functions similarly to bacillus Calmette-Guérin in the induction of cell-mediated hypersensitivity to inhaled antigens in bronchoalveolar cells. The successive demonstrations that both bacillus Calmette-Guérin and carrageenan could inflame the lung and permit the induction of cell-mediated hypersensitivity to inhaled antigens suggested that several other inflammatory agents can play a similar role. In addition, the present study demonstrated that long-term aerosol exposure to antigens is not necessary for the development of pulmonary cell-mediated hypersensitivity; the use of either bacillus Calmette-Guérin or carrageenan as a pulmonary inflammatory agent, together with 3 weeks of insufflation with pigeon dropping extract, resulted in the induction of cell-mediated hypersensitivity to the inhaled antigen in bronchoalveolar cells.