Integrins in Human Corneal Epithelium

Abstract

Monoclonal antibodies (Mabs) were used for immunohistochemical location of integrin beta- (beta 1,3, and 4) and alpha subunits (alpha 1-6 and alpha v) in the epithelium of both normal and tissue-cultured human cornea. Immunoreaction for the beta 1 integrin subunit was the most intense at the membranes of the basal epithelial cells and weaker at the superficial cell membranes. Anti-beta 4 immunofluorescence appeared in the basal part of the epithelium only, apposing the basement membrane. Both anti-alpha 2 and anti-beta 3 Mabs showed an immunoreaction with distribution similar to the beta 1 integrin subunit. Immunoreaction for the alpha 6 integrin subunit resembled the distribution of the beta 4 subunit. Anti-alpha v showed a faint immunoreaction at the basal and lateral aspects of the basal cell layer. Antisera against beta 3, alpha 1, alpha 4, and alpha 5 integrin subunits showed no specific reactions. The present results suggest that both the normal and tissue-cultured human corneal epithelium contain alpha 2 beta 1, alpha 3 beta 1, and probably also alpha v beta 1 and alpha 6 beta 4 integrin dimers or complexes. We discuss their role as possible receptors for some known ligands.