Envelope glycoprotein that forms spikes at the surface of the virion envelope. Participates in viral entry through an RGD motif that binds ITGAV-ITGB3. Membrane fusion is mediated by the fusion machinery composed at least of gB and the heterodimer gH/gL. May be involved in the fusion between the virion envelope and the outer nuclear membrane during virion egress. Homotrimer; disulfide-linked. Binds to heparan sulfate proteoglycans. Interacts with gH/gL heterodimer (By similarity). Interacts with host ITGAV-ITGB3; this interaction mediates viral entry. During virion morphogenesis, this protein probably accumulates in the endosomes and trans-Golgi where secondary envelopment occurs. It is probably transported to the cell surface from where it is endocytosed and directed to the trans-Golgi network (TGN). A proteolytic cleavage by host furin generates two subunits that remain linked by disulfide bonds. Belongs to the herpesviridae glycoprotein B family.