EXPRESSION OF HEPATITIS-B VIRUS CORE GENE-PRODUCTS WITH SPECIFIC IMMUNOREACTIVITY FOR E-ANTIGEN (HBEAG) IN SACCHAROMYCES-CEREVISIAE

The e antigen of the hepatitis B virus (HBeAg) was expressed in S. cer evisiae. Yeast-derived HBeAg exhibits high HBe antigenicity while lack ing any HBc antigenicity. The production yield of HBeAg expressed in y east is dependent on the host strains and the nature of the leader seq uences used in the plasmid constructions. The recombinant antigen is n ot secreted into the medium, independent from the leader sequences whi ch are used. A simple extraction procedure was developed, enabling the isolation of HBeAg from the cells without killing them. Recombinant H BeAg derived from yeast can replace plasma-derived antigen in ELISA fo r determining antibodies to HBeAg.