The expression, purification, and immunogenicity of a new chimeric virus-like particle.

Virus-like particles (VLPs) are highly immunogenic. In this study, gene fragments encoding hepatitis A virus (HAV) vp1 (aa 24-171), a hepatitis E virus (HEV) ORF2 gene fragment encoding aa 431-615, and gene fragments encoding a nine-peptide linker were spliced together. The spliced gene fragments were then inserted into the expression vector pBV220, resulting in the recombinant plasmid pBV-EA342, which expressed a 342-amino acid fusion protein. The fusion protein was expressed in Escherichia coli and specifically reacted to human hepatitis A- and E-positive sera. VLPs were formed during the renaturation of the EA342 fusion protein. The chimeric HAV and HEV VLPs were able to immunize KM mice, and they induced strong anti-HAV and anti-HEV humoral immune responses. These results are promising for future studies.