BACKGROUND: The junctional epithelium (JE) attaches the gingiva to the non-vital tooth surface and has other unusual properties which protect the underlying periodontal tissues. The JE differs from other gingival and oral epithelia in its unusual expression of cytokeratins typical of both stratifying and of simple epithelia, a phenotypic pattern possibly related to its specialized functions. METHODS: The patterns of differentiation of rodent gingival and other epithelia were examined using monoclonal antibodies against various glycoconjugates which are expressed on epithelial cell surfaces and provide an alternative marker system for regionally-differing patterns of cell maturation. RESULTS: Markers that are typical of basal cells in other stratifying epithelia were expressed by all cell strata of JE. JE lacked differentiation markers typical of other stratifying oral epithelial but showed suprabasal expression of markers typically expressed by simple epithelia and specialized epithelia, such as taste buds. CONCLUSIONS: The phenotype of rodent JE differs from that of other oral epithelia and the pattern of differentiation assessed by its expression of glycoconjugates parallels that for other phenotypic markers, such as cytokeratins. Differentiation of rodent JE is similar to that of human JE. The functional significance of these patterns of expression is not yet clear but the markers characterizing this unusual epithelium in rodents may be associated with its behavior in periodontal disease and of value to experimental studies of its development.
BACKGROUND: The junctional epithelium (JE) attaches the gingiva to the non-vital tooth surface and has other unusual properties which protect the underlying periodontal tissues. The JE differs from other gingival and oral epithelia in its unusual expression of cytokeratins typical of both stratifying and of simple epithelia, a phenotypic pattern possibly related to its specialized functions. METHODS: The patterns of differentiation of rodent gingival and other epithelia were examined using monoclonal antibodies against various glycoconjugates which are expressed on epithelial cell surfaces and provide an alternative marker system for regionally-differing patterns of cell maturation. RESULTS: Markers that are typical of basal cells in other stratifying epithelia were expressed by all cell strata of JE. JE lacked differentiation markers typical of other stratifying oral epithelial but showed suprabasal expression of markers typically expressed by simple epithelia and specialized epithelia, such as taste buds. CONCLUSIONS: The phenotype of rodent JE differs from that of other oral epithelia and the pattern of differentiation assessed by its expression of glycoconjugates parallels that for other phenotypic markers, such as cytokeratins. Differentiation of rodent JE is similar to that of human JE. The functional significance of these patterns of expression is not yet clear but the markers characterizing this unusual epithelium in rodents may be associated with its behavior in periodontal disease and of value to experimental studies of its development.