IMMUNOHISTOLOGICAL DETECTION OF THE BETA-SUBUNIT OF PROLYL 4-HYDROXYLASE IN RAT AND MINI PIG LUNGS WITH RADIATION-INDUCED PULMONARY FIBROSIS

Polyclonal and monoclonal antibodies to the beta subunit of prolyl 4-h ydroxylase, the protein disulphide isomerase, were used to compare the pulmonary cells in 13 normal and in 20 fibrotic rat and mini-pig lung s made fibrotic by X-ray irradiation, using the ABC immunoperoxidase t echnique. In normal lungs, prominent staining of Clara cells and type II pneumocytes and weaker reactivity with alveolar macrophages, fibrob lasts, endothelial and smooth muscle cells were detectable. In pulmona ry disease, in which interstitial fibrosis was the characteristic feat ure, the immunoreactivity was increased in both the epithelial and int erstitial cells. Type I pneumocytes remained negative, In the early st ages of disease (3 to 4 weeks after irradiation) when little morpholog ical alteration was seen, capillary endothelial cells had already beco me immunoreactive. These results underline the complex involvement and interaction of different lung cell populations in the process of pulm onary fibrogenesis.