LOCALIZATION OF IMMUNOREACTIVE TISSUE KALLIKREIN IN THE SEROMUCOUS GLANDS OF THE HUMAN AND GUINEA-PIG RESPIRATORY TREE

An immunocytochemical study focused on the cellular localization of ti ssue kallikrein along the human and guinea-pig respiratory tracts is r eported. A strong immunoreactivity for tissue kallikrein was observed in the seromucous glands of the nasal mucosa, trachea, and bronchi. In these glands, the immunostaining was restricted to the serous compone nt of the acinus whereas mucous cells showed no staining. Since no imm unoreactivity to kininogen was observed in any of the tissue constitue nts of the human and guinea-pig respiratory tree, transudation of the substrate from plasma was considered to be the preferred mode of deliv ery of the kininogen into the bronchopulmonary interstitium and lumen. Our results provide morphological evidence for the well documented pr esence of tissue kallikrein in bronchial lavage fluids and support the hypothesis that kinins may be one of the more important mediators inv olved during acute episodes of asthma and rhinitis.