The effect of complement depletion on hypersensitivity pneumonitis lesions induced by Micropolyspora faeni antigen.

Animals sensitized by intratracheal administration of particulate Micropolyspora faeni antigen and subsequently challenged with the antigen intratracheally developed lesions of hypersensitivity pneumonitis histologically similar to those observed in man wih this disease. Animals sensitized with antigen but depleted of complement with cobra venom factor prior to challenge with the antigen manifested a significant reduction in mean lesion indices when compared to a group of control animals that were not complement-depleted. These data indicate that complement is necessary for the development of pulmonary lesions of experimental hypersensitivity pneumonitis in the rabbit.