Expression of Integrins in Human Gingiva

Abstract

The distribution of the α 1-α6 subunits of β1 integrins was studied by using a panel of monoclonal antibodies in indirect immunofluorescence microscopy. The results showed that the β1 subunit was expressed at the cell membrane of basal cells of gingival epithelium, throughout the cells of junctional epithelium (JE), and in cells of connective tissue, including endothelial cells. The α1 subunit was expressed in vascular endothelial cells and, more faintly, in inflammatory cells in gingival connective tissue. The α4 subunit was expressed selectively in inflammatory cells, and the α5 subunit was expressed in cells throughout gingival connective tissue. An overall cell membrane immunoreactivity for the α2 and α3 subunits was shown in basal cells of gingival epithelium and in cells of JE, corresponding to the epithelial localization of the β1 subunit. The α6 subunit was polarized to the basal aspects of basal epithelial cells, but was also present in an overall cell surface distribution in basal cells and in cells of JE. The β4 integrin subunit was mainly expressed at the basal aspects of basal cells in gingival epithelium and JE. The results indicate that the α2/β1, α3/β 1, α6/β1, and α6/β 4 integrins are all expressed in human gingival epithelium. Of these, the α6/β4 integrin complex is the major candidate for mediation of the attachment of epithelial cells to the basement membrane facing the connective tissue and probably also the tooth.