Mapping of the dominant neutralizing antigenic site of a virus using infected cells

Panels of neutralizing monoclonal antibodies (MAbs) and antisera to vesicular stomatitis virus of the serotype Indiana (VSV-IND) were generated in mice and rats. They were used in competition studies to map epitopes on the viral glycoprotein that are involved in virus neutralization. Since neutralizing antibodies bind to the viral glycoproteins on the surface of intact viruses and of infected cells, infected cells were used for measuring the binding of competing antibodies by cytofluorometric analysis. A single immunodominant neutralizing epitope was recognised by 90% (58) of the MAbs including all of strong neutralizing capacity. 10% (6) of the neutralizing MAbs that all exhibited low neutralizing titers recognised spatially closely related epitopes. This approach offers a convenient method to determine antibody interaction with complex conformational epitopes of membrane proteins.