A comparative study of lysozyme and its secretion by tracheal epithelium

Tracheal explants from baboon, ferret, dog, mouse, hamster, rat guinea pig, chicken, sheep, rabbit and cat were maintained in vivo for 24 to 72 hr. Bathing media were analyzed for lysozyme content. Secretory rates were compared to the rate obtained for human trachea in our earlier work. These rates ranged from 807 micrograms lysozyme/g tissue/24 hr for human trachea to 11 micrograms lysozyme/g tissue/24 hr for chicken trachea. Secretory rates for baboon, ferret dog, mouse, hamster, rat, and guinea pig tracheal lysozyme fell within this range in decreasing order. No detectable lysozyme was released from sheep, cat, or rabbit explants. Lysozyme secretion did not correlate with the presence or absence of submucosal glands. Lysozyme from laboratory animals in all cases differed with respect to electrophoretic mobility and immunochemical properties from human lysozyme. These observations provide physiological, physiochemical, and immunochemical information which will facilitate the use of lysozyme to assess secretion of macromolecules in in vitro and in vivo studies of airway epithelium.