Study of the protective properties of immunodominant proteins of orthopoxviruses in various methods of immunization

Introduction. In 2022, the World Health Organization declared monkeypox a public health emergency. The monkeypox virus (MPV) is part of the Orthopoxvirus genus within the Poxviridae family. During replication, orthopoxviruses produce two distinct forms of viral particles: the extracellular enveloped virion (EEV), released via exocytosis, and the intracellular mature virion (IMV), released through cell lysis. These forms differ in surface proteins composition, influencing their immunogenicity and infectivity. Aim. To evaluate the immunogenic and protective activity of nine surface antigens of vaccinia virus. Materials and methods . Recombinant human adenoviruses type 2 (rAd2) carrying surface antigens of vaccinia virus were obtained using homologous recombination in bacteria, followed by adenoviral particle assembly in HEK293 cells. The immunogenic and protective properties of these adenoviruses were tested in BALB/c mice. The presence of antibodies to the vaccinia virus was assessed using ELISA, and survival rates were evaluated in a lethal infection model after intranasal challenge with the vaccinia virus strain Western Reserve. Results. The most immunogenic and protective antigens of the vaccinia virus within rAd2 were glycoprotein B5 of the EEV and membrane-associated protein H3 of the IMV, both showing 100% protective efficacy after intranasal immunization. Conclusion. Using a panel of recombinant adenoviruses carrying genes of vaccinia virus surface proteins, it was shown that optimal protection is achieved using a combination of enveloped and mature virion antigens. This method could be used for development of new multivalent preparations against various viral infections.