EXPRESSION OF HIV-1 EPITOPES INSERTED INTO THE NUCLEOCAPSID PROTEIN OF HUMAN HEPATITIS-B VIRUS

Hybrids of the core protein of hepatitis B virus (HBcAg)(5) were desig ned which carry N-terminal insertions of B- and T-cell epitopes of HIV -1: an immunodominant B-epitope from gp41, a T-cell epitope from p34 p ol, and a cluster of B- and T-cell epitopes from p17 gag. The hybrids were synthesized using two expression systems--one based on the thermo inducible P-R promoter of bacteriophage lambda and the other based on Phi 10 promoter of bacteriophage T7, with 3-5 and 7-14% yields, respec tively. The hybrids have dual HBV and HIV-1 immunospecificity and are assembled into particles similar to those formed by the protein carrie r HBcAg. Sandwich ELISA and immune electron microscopy revealed that t he HIV-1 epitopes are exposed on the surface of the particles.