Characterization and expression of a glycoprotein encoded by the Epstein-Barr virus BamHI I fragment

Computer-assisted analysis of the Epstein-Barr virus (EBV) open reading frame BILF2 (B95-8 nucleotides 150,525 to 149,782) predicts that it codes for a membrane-bound glycoprotein. [3H]glucosamine labeling of cells infected with vaccinia virus recombinants that expressed the BILF2 open reading frame revealed several diffuse species of glycoproteins of around 80,000 and 55,000 daltons. A monoclonal antibody derived from spleens of mice immunized with EBV immunoprecipitated the EBV-derived protein made by the vaccinia virus recombinants and also precipitated a late envelope glycoprotein with a mobility of 78,000 to 55,000 from EBV-producing cells. N-Glycanase treatment of the immunoprecipitated BILF2 product from EBV-producing cells resulted in a polypeptide of 28 kilodaltons, closely agreeing with the predicted molecular mass for the unmodified BILF2 gene product. Western (immuno-) blots using recombinant infected cells as a source of antigen showed that the majority of EBV-seropositive individuals have a serum antibody response to the BILF2-encoded gp78/55.