A universal design of betacoronavirus vaccines against COVID-19, MERS and SARS
Lianpan Dai 12
Tianyi Zheng 12
Kun Xu 12
Chuan Qin
Jinghua Yan
George F. Gao 13
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Published:June 28, 2020DOI:https://doi.org/10.1016/j.cell.2020.06.035
Summary
Vaccines are urgently needed to control the ongoing pandemic COVID-19 and previously-emerging MERS/SARS caused by coronavirus (CoV) infections. The CoV spike receptor-binding domain (RBD) is an attractive vaccine target but is undermined by limited immunogenicity. We describe a dimeric form of MERS-CoV RBD that overcomes this limitation. The RBD-dimer significantly increased neutralizing antibody (NAb) titers compared to conventional monomeric form and protected mice against MERS-CoV infection. Crystal structure showed RBD-dimer fully exposed dual receptor-binding motifs, the major target for NAbs. Structure-guided design further yielded a stable version of RBD-dimer as a tandem repeat single-chain (RBD-sc-dimer) which retained the vaccine potency. We generalized this strategy to design vaccines against COVID-19 and SARS, achieving 10-100-fold enhancement of NAb titers. RBD-sc-dimers in pilot scale production yielded high yields, supporting their scalability for further clinical development. The framework of immunogen design can be universally applied to other beta-CoV vaccines to counter emerging threats.
