Complete Freund's adjuvant-induced pneumonia in swine: a model of interstitial lung disease

Intravenously administered complete Freund's adjuvant, emulsified in saline, induced a lesion in the porcine lung characterized by a disseminated histiocytic interstitial pneumonia, type II pneumocyte proliferation and granulomatous arteriolitis. In addition, there was a persistent increase in numbers of alveolar macrophages. The lesion was well developed in 7 days. The sequential development and early resolution of the light microscopic lesions was studied for a period of 21 days after inoculation. The administration of Freund's adjuvant induced a spectrum of lesions typical of many forms of interstitial lung diseases of man and domestic animals. The pig is a suitable host for the investigation of the pulmonary inflammatory response and the repair mechanisms involved in chronic lung disease produced by infectious agents or environmental antigens.