SV40 virus-like particles as an effective delivery system and its application to a vaccine carrier

The authors have purified a major capsid protein, VP1 of Simian virus 40 (SV40), using recombinant baculovirus and have established the method of in vitro reassembly of SV40 virus-like particles (SV40-VLPs) from VP1-pentamers. In this reassembly, SV40-VLPs can encapsulate approximately 5 kb exogenous DNA shielded by histone or foreign proteins fused to minor capsid proteins VP2/3 and effectively deliver them into mammalian cells. Insertion of a particular foreign peptide into the surface loops of VP1 provides SV40-VLPs with the ability of cell targeting. Furthermore, SV40-VLPs appear to stimulate innate immunity as a natural adjuvant. Given these characteristics, SV40-VLPs may be a promising vaccine carrier to deliver heterologous antigens for the induction of cytotoxic T lymphocytes without artificial adjuvants. In this review, the authors describe how SV40-VLPs have been developed and engineered, and discuss their potential benefits and challenges as a cytotoxic T lymphocyte-based vaccine platform.