Marburg virus glycoprotein mRNA vaccine is more protective than a virus-like particle-forming mRNA vaccine.

Abstract

Although virus-like particle (VLPs) vaccines were shown to be effective against several viruses, their advantage over vaccines which include envelope protein only is not completely clear, particularly for mRNA-encoded VLPs. We conducted a side-by-side comparison of the immunogenicity and protective efficacy of mRNA vaccines encoding for the Marburg virus (MARV) full-length GP delivered alone or as a VLP. Electron microscopy confirmed VLP formation when MARV GP and matrix protein VP40 co-expressed. We vaccinated guinea pigs with a two-component mRNA vaccine encoding for GP and VP40 (VLP) or GP alone. At the highest dose, both vaccines protected fully, although the VLP vaccine elicited a slightly lower humoral response than the GP-only group. However, at low doses, GP-only mRNA conferred 100% protection, whereas the VLP exhibited only partial protection. In mice, VLP mRNA induced a moderate preference for GP-specific CD8+ T cells responses, whereas the GP-only mRNA somewhat favored CD4+ T cell responses. Guinea pig whole blood RNA-seq revealed that the VLP vaccine down-regulated genes associated with various biological and metabolic processes, including the NF-κB signaling pathway, whereas the GP-only vaccine upregulated interferon signaling. Overall, the VLP mRNA vaccine was less immunogenic and protective, whereas the GP-only mRNA vaccine conferred robust protection by as little as one µg dose in guinea pigs.