Effect of Monoclonal Antibodies to Epstein-Barr Virus Envelope Glycoproteins on Epstein-Barr Virus Neutralization and Binding to Target Cell Receptors

Abstract

Viral envelope glycoproteins are important in antiviral immunity; however, their precise role in both generating virus-neutralizing antibodies as well as in viral binding to target cell receptors remains largely unexplored. We studied nine monoclonal antibodies (MoAbs) to Epstein-Barr virus (EBV) envelope glycoproteins in order to define the role(s) of their respective epitopes in both EBV neutralization and binding to cellular receptors. Only four MoAbs neutralized EBV infectivity, one requiring complement, and only 1 of these 4 did inhibit EBV binding to target cell receptors. Our results suggest that (1) the epitopes recognized by a majority of these MoAbs play no role in viral neutralization and (2) that the majority of epitopes recognized by the neutralizing antibodies play no role in EBV binding to target cell receptors. This and previous studies would also suggest that only one epitope is involved in EBV binding to its receptor or that, until now, we were able to identify only one EBV-neutralizing MoAb (i.e., 72A1) which is specific for the receptor-binding viral epitope. It is probable that the epitope recognized by 72A1 MoAb is the only glycoprotein domain with a dual role, i.e., in EBV neutralization and binding to target cell receptors.