Barreiro, AntonioSisteré-Oró, MartaCebollada Rica, PaulaMeyerhans, AndreasFerrer, Laura2023-05-262023-05-262023Barreiro A, Prenafeta A, Bech-Sabat G, Roca M, Perozo Mur E, March R, et al. Preclinical evaluation of a COVID-19 vaccine candidate based on a recombinant RBD fusion heterodimer of SARS-CoV-2. iScience. 2023 Mar 17;26(3):106126. DOI: 10.1016/j.isci.2023.1061262589-0042http://hdl.handle.net/10230/56976Current COVID-19 vaccines have been associated with a decline in infection rates, prevention of severe disease, and a decrease in mortality rates. However, SARS-CoV-2 variants are continuously evolving, and development of new accessible COVID-19 vaccines is essential to mitigate the pandemic. Here, we present data on preclinical studies in mice of a receptor-binding domain (RBD)-based recombinant protein vaccine (PHH-1V) consisting of an RBD fusion heterodimer comprising the B.1.351 and B.1.1.7 SARS-CoV-2 variants formulated in SQBA adjuvant, an oil-in-water emulsion. A prime-boost immunisation with PHH-1V in BALB/c and K18-hACE2 mice induced a CD4+ and CD8+ T cell response and RBD-binding antibodies with neutralizing activity against several variants, and also showed a good tolerability profile. Significantly, RBD fusion heterodimer vaccination conferred 100% efficacy, preventing mortality in SARS-CoV-2 infected K18-hACE2 mice, but also reducing Beta, Delta and Omicron infection in lower respiratory airways. These findings demonstrate the feasibility of this recombinant vaccine strategy.application/pdfeng© 2023 The Author(s). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).info:eu-repo/semantics/articlehttp://dx.doi.org/10.1016/j.isci.2023.106126Health sciencesImmune responseImmunologyMicrobiologyinfo:eu-repo/semantics/openAccess