Expression of cytokeratins in human enamel organ

Cytokeratin (CK) is a filament which plays a central role in epithelial tis sue and, like the polypeptides of intermediate filaments in general, shows a high degree of tissue specificity. The CK expression patterns of odontoge nic epithelia are still poorly described. We studied the distribution of in dividual CK polypeptides in the human enamel organ at bell stage and in rem nants of the dental lamina. Our immunohistochemical study showed that epith elial cells stained for CKs 7, 13, 14 and 19 with slight changes in their p attern during the differentiation phase of odontogenesis. There was negativ e staining for all other CK polypeptides tested (CKs 8, 10, 16, 17 and 18). Most of the CKs in the enamel organ epithelia did not show differences rel ated to the stage-specific state of differentiation, except for CKs 14 and 19 at the inner enamel epithelium. A strong label for CK 14 was present at the inner dental epithelium at early bell stage, and this was substituted b y CK 19 at the late bell stage when the ameloblasts were fully differentiat ed.