Antigenicity and Immunogenicity of Recombinant Monkeypox Virus Antigens Expressed in Escherichia Coli Bacteria

Abstract

The recent mutant strains of Monkeypox virus (MPXV) have the ability to transmit among humans and spread rapidly to over 110 nations and regions. Several outer membrane proteins located at intracellular or extracellular viron can induce a strong immune response and generate high titers of neutralizing antibodies. These surface proteins of MPXV, known as protective antigens, include A29L, A35R, B6R, M1R, and E8L. Rapid preparation of recombinant antigens is very useful in the development of MPXV test kits or subunit vaccines against MPXV. In this study, five recombinant MPXV antigens were expressed in the E.coli system and purified using Ni affinity chromatograph or Ni affinity/ion-change chromatograph based on the proteins. Purified recombinant antigens (1-34mg/L) could be obtained within 48 hours after induction. All of recombinant antigens demonstrated good immunogenicity and raised antibodies with titers of 9841500, 170100, 76800, 170100 and 56700, which specifically bound to A29L, A35R, B6R, E8L and M1R, respectively. Each recombinant antigen showed a significant reaction with sera from MPXV recoverees or cross-reactivity with inactive VACV-induced antibodies, and sera from immunized mice also exhibited cross-reactivity with VACV lysate. In summary, our rapid preparation procedure can assist researchers in expressing and purifying recombinant MPXV antigens that meet the requirements of subunit vaccines or clinical diagnosis studies on a small scale.

Note:
Funding Information: This work was supported by the grants from the National Natural Science Foundation of China (No. 32070722), the National Science and Technology Major Project “Key New Drug Creation and Manufacturing Program” (2019ZX09201001) and the Foundation of National Facility for Translational Medicine (Shanghai) (TMSK -2020-134134134).

Declaration of Interests: All the authors declare that they have no conflict of interest.

Ethics Approval Statement: The animal study protocol was reviewed and approved by Institutional Animal Care and Use Committee of Shanghai Jiao Tong University (No. A2023102). Written informed consent was obtained from all participants, and the study was approved by the Research Ethics Committee of Beijing Youan Hospital Capital Medical University (approval reference number: LL-2023-009-K).

Keywords: monkeypox virus, antigen, E.coli, Immunogenicity, Vaccine