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bioRxiv · 10.1101/2023.04.03.534161

A broadly protective CHO cell expressed recombinant spike protein subunit based vaccine (IMT-CVAX) against SARS-CoV-2

Jitender,·Kumar, B. V.·Singh, S.·Verma, G.·Kumar, R.·Mishra, P. M.·Kumar, S.·Nagaraj, S. K.·Nag, J.·Joy, C. M.·Nikam, B.·Singh, D.·Pooja,·Kalidas, N.·Mumtaz,·Bhardwaj, A. K.·Mankotia, D. S.·Ringe, R. P.·Gupta, N.·Tripathi, S.·Mishra, R. P.
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Abstract

Protective immunity induced by COVID-19 vaccines is mediated mainly by spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we report the development of a recombinant prefusion stabilized SARS-CoV-2 spike protein-subunit-based COVID-19 vaccine produced in the mammalian cell line. The gene encoding ectodomain (ECD) of the spike protein was engineered and cloned into Freedom pCHO 1.0, a mammalian expression vector, and subsequently expressed in the Chinese Hamster Ovary suspension cell line (CHO-S). The recombinant S protein ectodomain (hereafter referred to as IMT-CVAX) was purified using a combination of tangential flow filtration and liquid chromatography. Biochemical and biophysical characterization of IMT-CVAX was done to ensure its vital quality attributes. Intramuscular immunization of mice with two doses of adjuvanted IMT-CVAX elicited a strong anti-Spike IgG response. In pseudovirus-based assays, IMT-CVAX- immune mice sera exhibited a broad-spectrum neutralization of several SARS-CoV-2 variants of concern (VoCs). Golden Syrian Hamster immunized with IMT-CVAX provided excellent protection against SARS-CoV-2 infection, and, hamster immune sera neutralized the live SARS-CoV-2 virus. The adjuvanted IMT-CVAX induced robust Tfh-cells response and germinal center (GC) reaction in human ACE2 receptor-expressing transgenic mice. The findings of this study may pave the way for developing next-generation protein subunit-based vaccines to combat the existing SARS-CoV-2 and its emerging VoCs. The IMT-CVAX is produced using a scalable process and can be used for large-scale vaccine production in an industrial setup.

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Jitender,, Kumar, B. V., Singh, S., Verma, G., Kumar, R., Mishra, P. M., Kumar, S., Nagaraj, S. K., Nag, J., Joy, C. M., Nikam, B., Singh, D., Pooja,, Kalidas, N., Mumtaz,, Bhardwaj, A. K., Mankotia, D. S., Ringe, R. P., Gupta, N., Tripathi, S., Mishra, R. P.. 2023-04-03. A broadly protective CHO cell expressed recombinant spike protein subunit based vaccine (IMT-CVAX) against SARS-CoV-2. https://doi.org/10.1101/2023.04.03.534161

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