Abstract
An immunocytochemical unlabelled antibody method using rabbit antihuman lysozyme, antirabbit immunoglobulin, and soluble rabbit antihorseradish peroxidase/horseradish peroxidase complexes was used to study the fine structural distribution of lysozyme in human bronchial glands. None was identified in mucous cells but there was heavy staining of the serous cell granules. The serous cell granules were not stained uniformly, suggesting the presence of other secretory products but lysozyme secretion appears to be a major function of these cells. The pathological implications of this are discussed.