The objective of this proposal is to further define the role of protease inhibitors in papain induced pulmonary inflammation and emphysema in the rabbit. It will be tested in this animal model whether or not complexes of alpha 1-anti-trypsin and alpha 2-macroglobulin exist in the pulmonary circulation in lung tussue and in alveolar macrophages. The methods that will be employed are chromatographic techniques, antigen-antibody crossed electrophoresis and immunofluorescence staining applied to histological sections. The intravascular half-life of 125 Iodine labeled alpha 1-antitrypsin and alpha 2-macroglobulin will also be determined in rabbits with induced inflammation, emphysema, and in controls. These experiments are intended to contribute to our understanding of the inflammatory process and the development of emphysema in the lung.