Monoclonal antibodies to herpes simplex virus type 1 glycoproteins show that epitope location influences virus neutralization

Three monoclonal antibodies, G8D1 , C2D2 , and TI57 , reacting with herpes simplex virus type 1 glycoproteins have been characterised according to the location of their epitope and ability to neutralize infective virus. Immune electron microscopy and a blocking radioimmunoassay were used to locate the epitopes. The results indicate that the epitope recognised by G8D1 is located on the surface of the glycoprotein fringe, whereas those recognized by C2D2 and TI57 are interior with respect to this. Only G8D1 has neutralizing activity alone, whereas C2D2 can neutralize when antiglobulin is added. Thus, epitope location and density determine the neutralizing capacity of individual antibody molecules.