Identification of antigenic sites on pseudorabies virus glycoprotein gp50 implicated in virus penetration of the host cell.

Five monoclonal antibodies specific for glycoprotein gp50 of pseudorabies virus were used to make a topographical map of gp50 and to determine the biological function of the different antigenic domains. Three antigenic domains were identified by competition binding assays and additivity assays (IA, IB, II). Domain IA corresponds to a continuous epitope, whereas domains IB and II consist of one or several discontinuous epitopes, identified by their resistance to heat or reducing treatments. Domains IA and IB correspond to sites highly involved in virus neutralization. Neutralization experiments by monoclonal antibodies recognizing domains IA and IB and performed before or after adsorption of virions to cells showed that these domains have a role in penetration of virus into the cell.