ANIMAL-MODEL OF HYPERSENSITIVITY PNEUMONITIS IN RABBIT - INDUCTION OF CELLULAR-HYPERSENSITIVITY TO INHALED ANTIGENS USING CARRAGEENAN AND BCG

Abstract

Previous studies indicated that long-term aerosol exposure to pigeon dropping extract, 1 of the etiologic agents of hypersensitivity pneumonitis, did not produce lung lesions. Inflaming the lungs with dead BCG and continued inhalation of pigeon dropping extract induced cell-mediated hypersensitivity to inhaled antigens in bronchoalveolar cells. Some inflammatory agent that affected the lung could probably induce cell-mediated hypersensitivity to inhaled antigens in human hypersensitivity pneumonitis. The present study shows that carrageenan, another inflammatory agent, functions similarly to BCG in the induction of cell-mediated hypersensitivity to inhaled antigens in bronchoalveolar cells. The successive demonstrations that BCG 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. Long-term aerosol exposure to antigens is not necessary for the development of pulmonary cell-mediated hypersensitivity; the use of BCG or carrageenan as a pulmonary inflammatory agent, together with 3 wk of insufflation with pigeon dropping extract, resulted in the induction of cell-mediated hypersensitivity to the inhaled antigen in bronchoalveolar cells.