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Design of a highly thermotolerant, immunogenic SARS-CoV-2 spike fragment

Malladi, SK and Singh, R and Pandey, S and Gayathri, S and Kanjo, K and Ahmed, S and Khan, MS and Kalita, P and Girish, N and Upadhyaya, A and Reddy, P and Pramanick, I and Bhasin, M and Mani, S and Bhattacharyya, S and Joseph, J and Thankamani, K and Raj, VS and Dutta, S and Singh, R and Nadig, G and Varadarajan, R (2021) Design of a highly thermotolerant, immunogenic SARS-CoV-2 spike fragment. In: Journal of Biological Chemistry, 296 .

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Official URL: https://doi.org/10.1074/jbc.RA120.016284


Virtually all SARS-CoV-2 vaccines currently in clinical testing are stored in a refrigerated or frozen state prior to use. This is a major impediment to deployment in resource-poor settings. Furthermore, several of them use viral vectors or mRNA. In contrast to protein subunit vaccines, there is limited manufacturing expertise for these nucleic-acid-based modalities, especially in the developing world. Neutralizing antibodies, the clearest known correlate of protection against SARS-CoV-2, are primarily directed against the receptorbinding domain (RBD) of the viral spike protein, suggesting that a suitable RBD construct might serve as a more accessible vaccine ingredient. We describe a monomeric, glycanengineered RBD protein fragment that is expressed at a purified yield of 214 mg/l in unoptimized, mammalian cell culture and, in contrast to a stabilized spike ectodomain, is tolerant of exposure to temperatures as high as 100 °C when lyophilized, up to 70 °C in solution and stable for over 4 weeks at 37 °C. In prime:boost guinea pig immunizations, when formulated with the MF59-like adjuvant AddaVax, the RBD derivative elicited neutralizing antibodies with an endpoint geometric mean titer of ∼415 against replicative virus, comparing favorably with several vaccine formulations currently in the clinic. These features of high yield, extreme thermotolerance, and satisfactory immunogenicity suggest that such RBD subunit vaccine formulations hold great promise to combat COVID-19

Item Type: Journal Article
Publication: Journal of Biological Chemistry
Publisher: American Society for Biochemistry and Molecular Biology Inc.
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Animal cell culture; Antibodies; Developing countries; Mammals; Nucleic acids; Vaccines; Viruses, Clinical testing; Developing world; Mammalian cell culture; Neutralizing antibodies; Protein fragments; Protein subunits; Receptor-binding domains; Thermotolerance, Diseases, mifamurtide; virus spike protein; ACE2 protein, human; coronavirus spike glycoprotein; neutralizing antibody; protein binding; recombinant protein; spike protein, SARS-CoV-2; vaccine; virus antibody; virus receptor, animal cell; animal experiment; antibody titer; Article; cell culture; controlled study; enzyme linked immunosorbent assay; Escherichia coli; female; freeze drying; guinea pig; heat tolerance; human; human cell; mammal cell; mouse; nonhuman; polyacrylamide gel electrophoresis; priority journal; protein degradation; protein domain; protein expression; protein motif; protein purification; protein stability; protein subunit; Severe acute respiratory syndrome coronavirus 2; size exclusion chromatography; temperature stress; thermal exposure; transmission electron microscopy; vaccine immunogenicity; virus replication; virus spike; Western blotting; administration and dosage; alpha helix; animal; beta sheet; binding site; biosynthesis; chemistry; genetics; heat; HEK293 cell line; immunology; metabolism; molecular model; prevention and control; vaccination; virology, Angiotensin-Converting Enzyme 2; Animals; Antibodies, Neutralizing; Antibodies, Viral; Binding Sites; COVID-19; COVID-19 Vaccines; Escherichia coli; Female; Guinea Pigs; HEK293 Cells; Hot Temperature; Humans; Immunogenicity, Vaccine; Models, Molecular; Protein Binding; Protein Conformation, alpha-Helical; Protein Conformation, beta-Strand; Protein Domains; Protein Interaction Domains and Motifs; Protein Stability; Receptors, Virus; Recombinant Proteins; SARS-CoV-2; Spike Glycoprotein, Coronavirus; Vaccination; Vaccine Potency
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 27 Apr 2023 08:44
Last Modified: 27 Apr 2023 08:44
URI: https://eprints.iisc.ac.in/id/eprint/81457

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