Poly(I:C) and CpG improve the assembly of foot-and-mouth disease virus-like particles and immune response in mice

Virus-like particles (VLPs) are extremely potent, safe, and serviceable vaccine platforms. Good assembly effi-ciency of VLPs is the key to reducing vaccine production costs and eliciting a robust immune response. This study adopted CpG and Poly (I:C) as scaffolds to facilitate the assembly of foot-and-mouth disease virus (FMDV) VLPs in vitro. The VLPs and the co-assembly products were characterized by particle size, zeta potential, gel retardation measurement, nuclease digestion experiments, size-exclusion chromatography, transmission electron microscopy and circular dichroism analysis. Our results indicated the successful encapsulation of CpG and Poly (I:C) inside VLPs without any effect on shape or size. Vaccination in mice also elicited a robust immune response. This study demonstrated that CpG and Poly (I:C) improved the efficiency of FMDV VLPs assembly and enhanced immune response, further proposing a new idea for improving the efficiency of VLPs assembly and enriching the in vitro VLPs assembly strategies.