An inactivated SARS-CoV-2 vaccine based on a Vero cell culture-adapted high-titer virus confers cross-protection in small animals

Anna Offersgaard*, Carlos R. Duarte Hernandez, Yuyong Zhou, Zhe Duan, Karen Anbro Gammeltoft, Katrine T. Hartmann, Ulrik Fahnøe, Pavel Marichal-Gallardo, Garazi Peña Alzua, Alexander P. Underwood, Christina Sølund, Nina Weis, Jesper Hansen Bonde, Jan P. Christensen, Gabriel K. Pedersen, Henrik Elvang Jensen, Kenn Holmbeck, Jens Bukh, Judith Margarete Gottwein

*Corresponding author for this work

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Abstract

Rapidly waning immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) requires continued global access to affordable vaccines. Globally, inactivated SARS-CoV-2 vaccines have been widely used during the SARS-CoV-2 pandemic. In this proof-of-concept study we adapted an original-D614G SARS-CoV-2 virus to Vero cell culture as a strategy to enhance inactivated vaccine manufacturing productivity. A passage 60 (P60) virus showed enhanced fitness and 50-fold increased virus yield in a bioreactor compared to the original-D614G virus. It further remained susceptible to neutralization by plasma from SARS-CoV-2 vaccinated and convalescent individuals, suggesting exposure of relevant epitopes. Monovalent inactivated P60 and bivalent inactivated P60/omicron BA.1 vaccines induced neutralizing responses against original-D614G and BA.1 viruses in mice and hamsters, demonstrating that the P60 virus is a suitable vaccine antigen. Antibodies further cross-neutralized delta and BA.5 viruses. Importantly, the inactivated P60 vaccine protected hamsters against disease upon challenge with original-D614G or BA.1 virus, with minimal lung pathology and lower virus loads in the upper and lower airways. Antigenicity of the P60 virus was thus retained compared to the original virus despite the acquisition of cell culture adaptive mutations. Consequently, cell culture adaptation may be a useful approach to increase yields in inactivated vaccine antigen production.

Original languageEnglish
Article number17039
JournalScientific Reports
Volume14
Issue number1
Number of pages18
ISSN2045-2322
DOIs
Publication statusPublished - 2024

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