Hepatitis C virus core protein fused to hepatitis B virus core antigen for serological diagnosis of both hepatitis C and hepatitis B infections by ELISA

The sequence encoding the truncated core protein (amino acids 1-98) of hepatitis C virus (HCc) was expressed in E. coli for production of HCc((1-98)), or fused with the truncated core antigen (HBcAg) and segments from the preS1 and preS2 regions from hepatitis B virus (HBV) for production of HBcPreS(1)PreS(2)HCc((1-98)). The HCc((1-98)) and HBcPreS(1)PreS(2)HCc((1-98)) proteins reacted with sera from HCV-infected individuals by immunoblot analyses, while the latter protein also exhibited HBV core antigenicity. They induced antibodies against HBcAg and/or HCV core protein in rabbits and in mice. Moreover, HBcPreS(1)PreS(2)HCc((1-98)) is more immunogenic than HCc((1-98)) in terms of anti-HCc induction. An ELISA that employed recombinant HCV core antigens of either HCc((1-98)) or HBcPreS(1)PreS(2)HCc((1-98)) to detect anti-HCc and/or anti-HBc antibodies was developed. Evaluation of serum samples with different status of HBV and HCV infections suggested that HCc((1-98)) might be suitable for the determination of antibodies against HCV core protein, while HBcPreS(1)PreS(2)HCc((1-98)) might be of value to detect HCV and/or HBV infection in donated blood in HBV low-prevalence countries. (C) 1999 Wiley-Liss, Inc.