Complement-bound human antibodies to vaccinia virus B5 antigen protect mice from virus challenge

A Quadrivalent mRNA Immunization Elicits Potent Immune Responses against Multiple Orthopoxviral Antigens and Neutralization of Monkeypox Virus in Rodent Models

The global outbreak of the 2022 monkeypox virus infection of humans and the 2023 documentation of a more virulent monkeypox in the Democratic Republic of the Congo raised public health concerns about the threat of human-to-human transmission of zoonotic diseases. Currently available vaccines may not be sufficient to contain outbreaks of a more transmissible and pathogenic orthopoxvirus. Development of a safe, effective, and scalable vaccine against orthopoxviruses to stockpile for future emergencies is imminent. In this study, we have developed an mRNA vaccine candidate, ALAB-LNP, expressing four vaccinia viral antigens A27, L1, A33, and B5 in tandem in one molecule, and evaluated the vaccine immunogenicity in rodent models. Immunization of animals with the candidate mRNA vaccine induced a potent cellular immune response and long-lasting antigen-specific binding antibody and neutralizing antibody responses against vaccinia virus. Strikingly, the sera from the vaccine-immunized mice cross-reacted with all four homologous antigens of multiple orthopoxviruses and neutralized monkeypox virus in vitro, holding promise for this mRNA vaccine candidate to be used for protection of humans from the infection of monkeypox and other orthopoxvirus.

Neutralization Determinants on Poxviruses

Smallpox was a highly contagious disease caused by the variola virus. The disease affected millions of people over thousands of years and variola virus ranked as one of the deadliest viruses in human history. The complete eradication of smallpox in 1980, a major triumph in medicine, was achieved through a global vaccination campaign using a less virulent poxvirus, vaccinia virus. Despite this success, the herd immunity established by this campaign has significantly waned, and concerns are rising about the potential reintroduction of variola virus as a biological weapon or the emergence of zoonotic poxviruses. These fears were further fueled in 2022 by a global outbreak of monkeypox virus (mpox), which spread to over 100 countries, thereby boosting interest in developing new vaccines using molecular approaches. However, poxviruses are complex and creating modern vaccines against them is challenging. This review focuses on the structural biology of the six major neutralization determinants on poxviruses (D8, H3, A27, L1, B5, and A33), the localization of epitopes targeted by neutralizing antibodies, and their application in the development of subunit vaccines.

Immunogenic proteins and potential delivery platforms for mpox virus vaccine development: A rapid review

Since May 2022, the mpox virus (MPXV) has spread worldwide and become a potential threat to global public health. Vaccines are important tools for preventing MPXV transmission and infection in the population. However, there are still no available potent and applicable vaccines specifically for MPXV. Herein, we highlight several potential vaccine targets for MPVX and emphasize potent immunogens, such as M1R, E8L, H3L, A29L, A35R, and B6R proteins. These proteins can be integrated into diverse vaccine platforms to elicit powerful B-cell and T-cell responses, thereby providing protective immunity against MPXV infection. Overall, research on the MPXV vaccine targets would provide valuable information for developing timely effective MPXV-specific vaccines.

Development of multi-epitope vaccines against the monkeypox virus based on envelope proteins using immunoinformatics approaches

Background

Since May 2022, cases of monkeypox, a zoonotic disease caused by the monkeypox virus (MPXV), have been increasingly reported worldwide. There are, however, no proven therapies or vaccines available for monkeypox. In this study, several multi-epitope vaccines were designed against the MPXV using immunoinformatics approaches.

Methods

Three target proteins, A35R and B6R, enveloped virion (EV) form-derived antigens, and H3L, expressed on the mature virion (MV) form, were selected for epitope identification. The shortlisted epitopes were fused with appropriate adjuvants and linkers to vaccine candidates. The biophysical andbiochemical features of vaccine candidates were evaluated. The Molecular docking and molecular dynamics(MD) simulation were run to understand the binding mode and binding stability between the vaccines and Toll-like receptors (TLRs) and major histocompatibility complexes (MHCs). The immunogenicity of the designed vaccines was evaluated via immune simulation.

Results

Five vaccine constructs (MPXV-1-5) were formed. After the evaluation of various immunological and physicochemical parameters, MPXV-2 and MPXV-5 were selected for further analysis. The results of molecular docking showed that the MPXV-2 and MPXV-5 had a stronger affinity to TLRs (TLR2 and TLR4) and MHC (HLA-A*02:01 and HLA-DRB1*02:01) molecules, and the analyses of molecular dynamics (MD) simulation have further confirmed the strong binding stability of MPXV-2 and MPXV-5 with TLRs and MHC molecules. The results of the immune simulation indicated that both MPXV-2 and MPXV-5 could effectively induce robust protective immune responses in the human body.

Conclusion

The MPXV-2 and MPXV-5 have good efficacy against the MPXV in theory, but further studies are required to validate their safety and efficacy.