Expression of an early Epstein-Barr virus antigen (EA-D) in E. coli. Brief report.

The 1.34 kb BcII-BgIII-fragment of the BamHI-M region of Epstein-Barr virus genome, comprising the complete BMRF1 open reading frame, was cloned into the tryptophan regulated E. coli expression vector pATH1. The resulting fusion protein, having a molecular weight of 80 kd, is recognized not only by anti-early antigen (EA)-positive human sera but also by the monoclonal antibody R3 directed against the diffuse component of EA (EA-D). A possible use for this fusion protein as an indicator protein in diagnosis of IgA antibodies against EA-D is presented.