CD48 BINDS TO HEPARAN-SULFATE ON THE SURFACE OF EPITHELIAL-CELLS

CD48 is a member of the immunoglobulin superfamily whose cell surface expression is strikingly up-regulated on the surface of Epstein-Barr v irus-infected B cells. To date, no ligand for human CD48 has been char acterized. In this study, we show that human recombinant CD48 binds to the glycosaminoglycan heparan sulfate on the surface of human epithel ial cells. We have produced a monoclonal antibody (615) against epithe lial cell surfaces that blocks this binding and show that it too recog nizes heparan sulfate. The specific epitope on heparan sulfate that is recognized by the antibody and is involved in binding is also express ed in vivo on the basolateral surfaces of mucosal epithelium and lamin a propria.