Mosaic hepatitis B virus core particles allow insertion of extended foreign protein segments.

This is the authors' abstract. We don't add key points for this paper.

Because of its particular immunological properties, the core protein of hepatitis B virus (HBcAg) has become one of the favoured 'virus-like particles' for use as a carrier of foreign epitopes. A new strategy to construct core particles presenting extended foreign protein segments was established based on the introduction of a linker containing a translational stop codon between sequences encoding a C-terminally truncated HBcAg (HBcAg delta) and a foreign protein sequence. Expression in an Escherichia coli suppressor strain allowed the simultaneous synthesis of both HBcAg delta and a read-through fusion protein containing a part of the hantavirus nucleocapsid protein. After purification, the presence of core-like mosaic particles with HBc and hantavirus antigenicity was demonstrated by electron microscopy and immunological tests. This strategy of partial stop codon suppression should improve the use of HBcAg as a carrier of foreign epitopes by allowing insertion of long foreign sequences into particle-forming proteins. The resulting mosaic particles should be of general interest for further vaccine developments.