Co-expression of the Epstein-Barr virus BXLF2 and BKRF2 genes with a recombinant baculovirus produces gp85 on the cell surface with antigenic similarity to the native protein.

Glycoprotein H (gH) is a conserved herpesvirus gene product functionally implicated in the penetration of the virus into the host cell. Other human herpesviruses require an accessory glycoprotein named gL for the synthesis of mature gH. We constructed a series of recombinant baculoviruses to determine whether gL expression can overcome the constraints upon Epstein-Barr virus (EBV) gH (gp85) folding and transport in this expression system. When gH and gL were co-expressed some EBV gH was transported to the insect cell surface. Deletion of 27 amino acids from the gH carboxy terminus resulted in the secretion of an 80 kDa protein (gHt) into the culture medium when it was expressed either in the presence or absence of gL and this protein could also be immunoprecipitated with E1D1. In contrast, gL was not secreted into the culture medium. Our results suggests that either co-expression of gH with gL or removal of the predicted transmembrane anchor sequence can overcome some of the constraints upon EBV gH expression in the baculovirus system.