1. Development of a Recombinant Omicron BA.1 Subunit Vaccine Candidate in Pichia pastoris.
- Author
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Kalyoncu S, Sayili D, Kuyucu AZ, Soyturk H, Gullu S, Ersayan B, Tarman IO, Avci ME, Mert O, Haskok U, Tekin E, Akinturk H, Orkut R, Demirtas A, Tilmensagir I, Ulker C, Gungor B, and Inan M
- Subjects
- Animals, Mice, Vaccines, Synthetic immunology, Vaccines, Synthetic genetics, Vaccines, Synthetic administration & dosage, Saccharomycetales genetics, Saccharomycetales immunology, Saccharomycetales metabolism, Immunoglobulin G blood, Mice, Inbred BALB C, Female, Recombinant Proteins immunology, Recombinant Proteins genetics, Antibodies, Neutralizing blood, Antibodies, Neutralizing immunology, Vaccine Development, Adjuvants, Immunologic administration & dosage, Pichia genetics, Pichia metabolism, Humans, Spike Glycoprotein, Coronavirus immunology, Spike Glycoprotein, Coronavirus genetics, Spike Glycoprotein, Coronavirus chemistry, Vaccines, Subunit immunology, Vaccines, Subunit genetics, Vaccines, Subunit administration & dosage, COVID-19 Vaccines immunology, COVID-19 Vaccines genetics, COVID-19 Vaccines administration & dosage, Antibodies, Viral blood, Antibodies, Viral immunology, SARS-CoV-2 immunology, SARS-CoV-2 genetics, COVID-19 prevention & control, COVID-19 immunology
- Abstract
Low-cost and safe vaccines are needed to fill the vaccine inequity gap for future pandemics. Pichia pastoris is an ideal expression system for recombinant protein production due to its cost-effective and easy-to-scale-up process. Here, we developed a next-generation SARS-CoV2 Omicron BA.1-based recombinant vaccine candidate expressed in P. pastoris. The receptor binding domain of Omicron BA.1 spike protein (RBD-Omicron) was produced at 0.35 g/L in supernatant. With a 60% recovery after two-step purification, RBD-Omicron showed 99% purity. After in vitro characterisation of purified RBD-Omicron via chromatography, mass spectrometry, calorimetry and surface plasmon resonance-based methods, it was injected into mice for immunization studies. Three different doses of Alum and CpG adjuvanted RBD-Omicron were investigated and 10 μg RBD-Omicron gave the highest antigenicity. After two doses of vaccination, IgG titers in mice serum reached to more than 10
6 . These serum antibodies also recognized earlier (Delta Plus: B.1.617.2) and later (Eris: EG.5, Pirola: BA.2.86) SARS-CoV2 variants. The long-term immunological response in mice was measured by analyzing serum antibody titers and T-cell response of splenocytes after 60 weeks. Interestingly, IgG titers and Th1 response were significantly high even after a year. Omicron subvariants are dominantly circulating in the world, so Omicron sub-lineage-based vaccines can be used for future pandemics. The RBD-Omicron-based vaccine candidate developed in this study is suitable for technology transfer and transition into the clinic., (© 2025 The Author(s). Microbial Biotechnology published by John Wiley & Sons Ltd.)- Published
- 2025
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