Characterization of epitopes on native and denatured forms of herpes simplex virus glycoprotein B

Herpes simplex virus 1 glycoprotein B (gB) is an envelope glycoprotein which promotes fusion of virions with the cell membrane. This report characterizes the epitopes on native, disulfide-linked dimers of gB and monomeric forms of the glycoprotein using a panel of monoclonal antibodies. The antibodies were divided into groups, based on immune reactions with denatured or native forms of gB. The first group reacted with discontinuous epitopes assembled on gB dimers but failed to detect native or denatured monomers. In contrast, the second group reacted with denatured gB recognizing continuous epitopes on the parent oligomer and monomeric forms. Comparison of gB dimers formed by HFEM and tsB5 revealed that mutant forms specified altered immunological properties. Analysis of gB made in Vero cells showed that discontinuous epitopes were retained whereas a subset of continuous ones were lost on the cleavage products. Results of this study indicate that more than half of the epitopes on gB are generated by juxtaposing amino acids from one or more gB subunits and differ from continuous epitopes present on both forms of the molecule.