Expression of the Epstein-Barr virus gp350/220 gene in rodent and primate cells

The gene encoding the Epstein-Barr virus envelope glycoproteins gp350 and gp220 was inserted downstream of the cytomegalovirus immediate-early, Moloney murine leukemia virus, mouse mammary tumor virus, or varicella-zoster virus gpI promoters in vectors containing selectable markers. Host cell and recombinant vector systems were defined which enabled the isolation of rodent or primate cell clones which expressed gp350/220 in substantial quantities. Continued expression of gp350/220 required maintenance of cells under positive selection for linked markers and periodic cloning. gp350/220 expressed in various host cells varied slightly in electrophoretic mobility, probably reflecting differences in glycosylation. Insertion of a stop codon into the gp350/220 open reading frame, upstream of the putative membrane anchor sequence, resulted in efficient secretion of truncated gp350 and gp220 from rat pituitary (GH3) cells. gp350/220 expressed in mammalian cells is highly immunogenic and elicits virus-neutralizing antibodies when administered to mice.