Intercellular adhesion molecule-1 expression on human corneal epithelial outgrowth from limbal explant in culture

Aim: To investigate the relation between intercellular adhesion molecule (ICAM)-1 expression and cellular dynamics occurring concomitantly with epithelial cell movement. Methods: Outgrowing epithelial sheets of human corneal epithelial (HCE) cells from cultured limbal explants were examined by immunoperoxidase staining with anti-ICAM-1 monoclonal antibody. An adhesion assay was performed using the epithelial sheets of HCE cells and an Epstein-Barr virus (EVB) infected B cell lymphoma cell line (EVB(+)BJAB) expressing CD1 1a/CD18, a counter-receptor of ICAM-1. Also, the effect of calphostin C, a specific protein kinase C (PKC) inhibitor, on ICAM-1 expression on the outgrowing epithelial sheets of HCE cells was examined. Results: Strong positive staining for ICAM-1 was found predominantly on HCE cells in the marginal segment of the epithelial sheet, particularly on the cells at the leading edge. EBV(+)BJAB cells adhering to the HCE cells corresponded well to the area of ICAM-1 staining. Treatment of outgrowing epithelial sheets with calphostin C markedly decreased the ICAM-1 expression on the HCE cells. Conclusion: ICAM-1 is actively expressed on HCE cells in the marginal segment of the outgrowing epithelial sheets where there is active movement mediated through a PKC dependent mechanism, suggesting the role of ICAM-1 in epithelial cell motility such as the spreading and migration of cells.