Changes in cell phenotype during regeneration of junctional epithelium of human gingiva in vitro.

The relationship between cell attachment and the phenotype of the attached oral epithelial cells was studied by comparing junctional epithelium (JE) with a culture model for JE in which epithelial cells form an equivalent organization of tissues. Gingival explants were cultured on either a high or a low protein-binding membrane. The cut edge of epithelium and connective tissue was placed on the membrane; epithelial cells migrated to form a sheet of tissue between the explant and the membrane substratum. Cells which grew in contact with the high protein-binding membrane attached to the substratum and assumed a cuboidal shape. With time in culture these cells showed a decrease in reactivity with antibodies to psi-3 antigen (an antigen associated with epithelial migration) and an increase in reactivity with antibodies to cytokeratin 19 (a marker for JE). Cells grown on the low protein-binding membrane did not exhibit changes in shape or antigens. Because similar features were found in the JE in vivo, it was concluded that the junctional cells which are directly attached to the tooth (DAT cells) have a nonmigratory phenotype that develops as a response to the tooth surface. Because the cells are in contact with a metabolically inert material the changes appear to be largely self-induced. The culture method allows studies on putative inducer molecules and on mechanisms which may control the phenotype of epithelial cells at the dentogingival interface.