ABSTRACT
Background Vaccines that incorporate multiple SARS-CoV-2
antigens can further broaden the breadth of virus-specific cellular and
humoral immunity. This study describes the development and
immunogenicity of SARS-CoV-2 VLP vaccine that incorporates the 4
structural proteins of SARS-CoV-2.
Methods VLPs were generated in transiently transfected HEK293
cells, purified by multimodal chromatography and characterized by
tunable resistive pulse sensing, AFM, SEM, and TEM. Immunoblotting
studies verified the protein identities of VLPs. Cellular and humoral
immune responses of immunized animals demonstrated the immune potency of
the formulated VLP vaccine.
Results Transiently transfected HEK293 cells reproducibly
generated vesicular VLPs that were similar in size to and expressing all
four structural proteins of SARS-CoV-2. Alum adsorbed, K3-CpG ODN
adjuvanted VLPs elicited high titer anti-S, anti-RBD, anti-N IgG,
triggered multifunctional Th1 biased T cell responses, reduced virus
load and prevented lung pathology upon live virus challenge in
vaccinated animals.
Conclusion These data suggest that VLPs expressing all four
structural protein antigens of SARS-CoV-2 are immunogenic and can
protect animals from developing COVID-19 infection following
vaccination.