Recombinant Modified Vaccinia Virus Ankara Generating Ebola Virus-Like Particles

Abstract

There are currently no approved therapeutics or vaccines to treat or protect against the severe hemorrhagic fever and death caused by Ebola virus (EBOV). Ebola virus-like particles (EBOV VLPs) consisting of the matrix protein VP40, the glycoprotein (GP), and the nucleoprotein (NP) are highly immunogenic and protective in nonhuman primates against Ebola virus disease (EVD). We have constructed a modified vaccinia virus Ankara-Bavarian Nordic (MVA-BN) recombinant coexpressing VP40 and GP of EBOV Mayinga and the NP of Taï Forest virus (TAFV) (MVA-BN-EBOV-VLP) to launch noninfectious EBOV VLPs as a second vaccine modality in the MVA-BN-EBOV-VLP-vaccinated organism. Human cells infected with either MVA-BN-EBOV-VLP or MVA-BN-EBOV-GP showed comparable GP expression levels and transport of complex N-glycosylated GP to the cell surface. Human cells infected with MVA-BN-EBOV-VLP produced large amounts of EBOV VLPs that were decorated with GP spikes but excluded the poxviral membrane protein B5, thus resembling authentic EBOV particles. The heterologous TAFV NP enhanced EBOV VP40-driven VLP formation with efficiency similar to that of the homologous EBOV NP in a transientexpression assay, and both NPs were incorporated into EBOV VLPs. EBOV GP-specific CD8 T cell responses were comparable between MVA-BN-EBOV-VLP-and MVA-BN-EBOV-GP-immunized mice. The levels of EBOV GP-specific neutralizing and binding antibodies, as well as GP-specific IgG1/IgG2a ratios induced by the two constructs, in mice were also similar, raising the question whether the quality rather than the quantity of the GP-specific antibody response might be altered by an EBOV VLPgenerating MVA recombinant.IMPORTANCE The recent outbreak of Ebola virus (EBOV), claiming more than 11,000 lives, has underscored the need to advance the development of safe and effective filovirus vaccines. Virus-like particles (VLPs), as well as recombinant viral vectors, have proved to be promising vaccine candidates. Modified vaccinia virus Ankara-Bavarian Nordic (MVA-BN) is a safe and immunogenic vaccine vector with a large capacity to accommodate multiple foreign genes. In this study, we combined the advantages of VLPs and the MVA platform by generating a recombinant MVA-BN-EBOV-VLP that would produce noninfectious EBOV VLPs in the vaccinated individual. Our results show that human cells infected with MVA-BN-EBOV-VLP indeed formed and released EBOV VLPs, thus producing a highly authentic immunogen. MVA-BN-EBOV-VLP efficiently induced EBOV-specific humoral and cellular immune responses in vaccinated mice. These results are the basis for future advancements, e.g., by including antigens from various filoviral species to develop multivalent VLP-producing MVA-based filovirus vaccines.

Distinct Immunogenicity and Efficacy of Poxvirus-Based Vaccine Candidates against Ebola Virus Expressing GP and VP40 Proteins

“…The edited GP protein allows the expression of the full-length GP protein and avoids the expression of the secreted GP protein, as previously reported for other EBOV vaccine candidates (48). Furthermore, the use of human codon-optimized VP40 proteins has been recently reported for other EBOV vaccines (49). As the sole membrane protein encoded by the ebolavirus species, the GP plays a critical role in the entry and pathogenicity of EBOV and SUDV (50,51) and is a highly immunogenic protein containing both T-and B-cell epitopes able to activate T-and B-cell ebolavirusspecific immune responses that are associated with survival or asymptomatic infection (52,53).…”

A Pentavalent Epstein-Barr Virus-Like Particle Vaccine Elicits High Titers of Neutralizing Antibodies against Epstein-Barr Virus Infection in Immunized Rabbits

“…Thus, in its current state, our system is hindered by low productivity relative to the number of cells needed to produce a small working VLP stock for animal experiments, with no potential for scalability. To boost overall immunogenicity, establish efficient and robust expression of all glycoproteins, and improve efficiency and scalability of the EBV-LP production process, future studies will explore the use of live-attenuated vectors, such as modified vaccinia Ankara (MVA), chimpanzee adenovirus 3, and/or vesicular stomatitis virus to deliver EBV-LPs and EBV antigens, as was done recently for Ebola virus with very promising results in pre-clinical and Phase Ib clinical trials [66][67][68][69][70][71][72][73]. In the field of EBV vaccinology, viral vaccine vectors, particularly adenoviral and MVA vectors, have been used both pre-clinically and clinically in the context of therapeutic and prophylactic vaccination.…”

Filovirus – Auslöser von hämorrhagischem Fieber

“…Zu den Impfstoff-Kandidaten zählen z. B. DNA-Vakzine, virus like par ticles (VLP), rekombinantes humanes Parainfluenzavirus und MVA-BN-EBOV-VLP (MVA -modified virus Ankara) [171]. Eine auf Rabiesvirus basierte bivalente Vakzine wurde entwickelt [172].…”