EXPRESSION OF SQUAMOUS-CELL CARCINOMA ANTIGEN, A SERINE-PROTEASE INHIBITOR, IN THE INTEGUMENT OF VERTEBRATES - POSSIBLE ROLE PN STRATIFICATION OF EPIDERMIS

Terrestrial vertebrates, particularly eutherian species, show highly s tratified epithelium. Recent evidence has indicated that the special o rganization of the stratification depends largely upon a variety of ad hesion molecules, and therefore probably upon some proteases and their inhibitors. The present paper shows the expression of squamous cell c arcinoma antigen (SCC antigen), a new serine protease inhibitor, in th e integuments of various vertebrate species. In Southern blot analysis , SCC antigen gene was detected in human, monkey, dog, cat, horse, cow , goat, and rabbit, but not in wallaby, chicken, tortoise, frog, or ca rp. Immunohistochemical studies with the monoclonal antibody against S CC antigen revealed that this protein is present at the intermediate l ayer of the human squamous epithelium but not at the parabasal layer. SCC antigen is also absent at the epithelial region adjacent to the sq uamo-columnar junction where the stratification is not fully organized yet. These results indicate that SCC antigen may play an important ro le in the regulation of the stratification of squamous epithelium.