Histoenzymology of the lung. II. The behaviour of lung hydrolytic enzymes during some experimental pulmonary processes.

The enzymic activity of acid alkaline phosphatases, of alanyl- and leucine-aminopeptidases, of beta-galactosidase and beta-glucuronidase, and of Tween-60-esterase was tested in the rabbit lung tissue during the following experimental processes: a) the sensitization with Freund adjuvant containing PPD and challenge of the delayed hypersensitivity reaction to PPD), b) the sensitization with gamma-globulin in Freund adjuvant, c) the pulmonary Arthus reaction, d) the lung granulomas induced by intravenous administration of Freund adjuvant containing heterologous lung proteins, e) the tuberculosis and silicotuberculosis under the influence of tuberculostatics. A metabolic intensification expressed by a marked increase of the tested hydrolytic enzymes was observed comparatively with controls in all these immune, granulomatous and inflammatory processes experimentally induced in the lung. The morphologic substrate of this behaviour was represented by the numerous cell proliferation and differentiations of the reticulomacrophagic type occurring during these experimental processes under the stimulation of antigenic elicitors. The latter also induced an increase of the lysosome-formation as submicroscopic site of these hydrolytic enzymes.