The development of granulomatous pulmonary inflammation in rabbits by aerosol challenge: I. Release of plasminogen activator by alveolar macrophages

A rabbit model of hypersensitivity pneumonitis (HP) was employed to evaluate the release of plasminogen activator (PA) as a method for monitoring the degree of pulmonary inflammation. PA release from alveolar macrophages (AM) was shown to coincide with inflammation and was maximal at approximately 2 weeks of aerosol challenge. PA release could also be induced in normal AM by peripheral lymphocytes obtained from sensitized animals after incubation with antigen. Unseparated peripheral blood mononuclear cells from experimental animals also exhibited antigen-induced PA release. These results suggest that the measurement of PA release using several different cell populations can be used to evaluate pulmonary inflammation in HP.