CHIMERIC POTYVIRUS-LIKE PARTICLES AS VACCINE CARRIERS

Presentation of subunit vaccines in a highly ordered aggregate form ca n result in enhanced immune responses. Coat protein (CP) monomers of a potyvirus (Johnsongrass mosaic virus) when produced in heterologous h ost expression systems (Escherichia coli, yeast and insect cells) self -polymerized to produce potyvirus-like particles (PVLPs). The N- and C -terminal regions of potyvirus CP are surface-exposed and are not requ ired for assembly. Hybrid CP monomers containing short peptides fused to their N- and/or C-termini, or large target antigens fused to the N- terminus or replacing most of the N- or C-terminal exposed regions ret ained the ability to assemble into hybrid PVLPs. Such chimeric PVLPs w ere highly immunogenic in mice and rabbits even in the absence of any adjuvant. Potyvirus CP is highly versatile in accommodating peptides o r large antigens and is able to present antigens exposed on the surfac e of virus-like particles. This, combined with the efficiency of high level bacterial and insect cell expression systems, makes PVLPs an att ractive non-pathogenic and non-replicative vaccine carrier.