The conversion of hepatitis B core antigen synthesized in E coli into e antigen.

The antigen (HBeAg) of hepatitis B virus (HBV) is a polypeptide of 17-20,000 daltons closely associated with the core antigen (HBcAg) of Dane particles, from which it is released by a variety of disruptive procedures. HBeAg could be a unique component of HBV core particles or a derivative of HBcAg. To resolve this question immunodiffusion experiments were carried out with preparations of HBcAg synthesized in E coli carrying a recombinant plasmid from which the HBcAg, but no other HBV gene, was expressed. HBcAg was converted into HBeAg by proteolytic degradation under dissociating conditions, thus confirming at the molecular level that HBeAg is a component of HBcAg. This offers a new route to the detection of HBeAg and antibodies to the antigen.