Chimeric recombinant rotavirus-like particles as a vehicle for the display of heterologous epitopes

In order to improve the presentation and immunogenicity of single epitopes, virus-like particles (VLPs) are being used as platforms for the display of foreing epitopes on their surface. The rotavirus major capsid protein VP6 has the ability to self-assemble into empty non-infectious VLPs. In the present study, we analyzed the use of double layered VLPs (made up of VP2 and VP6 rotavirus proteins) as carriers to display a 14 amino acid epitope fused to three different aminoacidic regions of VP6 exposed on the surface of VLPs. Although all chimeric protein were correctly expressed in insect cells, only one of them resulted in spontaneous assembly of VLPs displaying the heterologous epitope on their surface, confirmed by sandwich ELISA and electron microscopy. Furthermore, the injection of chimeric VLPs into mice elicited higher antibody titers than the monomeric chimeric protein. Our results identify an specific amino acid region of VP6 which allows the insertion of at least a 14 amino acid heterolgous epitope and demonstrate its potential as immunogenic carrier.