Staining patterns of rodent squamous epithelia by monoclonal anti-keratin antibodies

Anti-keratin staining patterns were examined by immunofluorescence in the epidermis, oral mucosa and forestomach of rats and mice by monoclonal antibodies AE1 and AE2. In contrast to human tissues enzymatic pretreatment of sections was necessary even when fresh-frozen tissue was used, suggesting masking of the antigens in vivo. AE1 stained the cytoplasm of spinous cells in most epithelia, whereas basal cell staining varied. AE2 showed suprabasal cytoplasmic staining in epidermis, forestomach and palate, whereas the other epithelia were stained only in keratohyalin granules and membranes of cornified cells. In some epithelia a small number of irregularly distributed basal cells stained positive with AE2, indicating heterogeneity in the basal cell compartment. Thus, the anti-keratin staining pattern varies both regionally and, as earlier shown in human epithelium, with the stage of maturation of cells within a given epithelium. The present study provides a basis for further studies of epithelial differentiation during normal and pathologic development.