摘要
With continuous mutations of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),the severe immune escape of Omicron sub-variants urges the development of next-generation broad-spectrum vaccines,especially as booster jabs after high-level vaccination coverage of inactivated vaccines in China and many other countries.Previously,we developed a coronavirus disease 2019(COVID-19)protein subunit vaccine ZF2001?based on the tandem homo-prototype receptor-binding domain(RBD)-dimer of the SARS-CoV-2 spike protein.We upgraded the antigen into a hetero-chimeric prototype(PT)-Beta or Delta-BA.1 RBD-dimer to broaden the cross-protection efficacy and prove its efficiency with protein subunit and mRNA vaccine platforms.Herein,we further explored the hetero-chimeric RBD-dimer mRNA vaccines and evaluated their broad-spectrum activities as booster jabs following two doses of inactivated vaccine(Ⅳ)in mice.Our data demonstrated that the chi-meric vaccines significantly boosted neutralizing antibody levels and specific T-cell responses against the vari-ants,and PT-Beta was superior to Delta-BA.1 RBD as a booster in mice,shedding light on the antigen design for the next-generation COVID-19 vaccines.
基金
This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(grant number XDB29040203)
the National Key Research and Development Program of China(grant number 2021YFA1301404 and 2020YFA0907102)
the National Natural Science Foundation of China(grant numbers 82225021 and 32171428)
In addition,Qihui Wang was supported by the CAS Project for Young Scientists in Basic Research(grant number YSBR-010)
the Youth Innovation Promotion Association of the CAS(grant number Y2022037).We thank Professor Xiao Zhao from the National Center for Nanoscience and Technology for sharing the LNP encapsulation and DLS platforms.We thank Dr.Kun Xu for his help during the revision of this manuscript.We thank Linjie Li for sharing recombinant RBD proteins.We thank the Institutional Center for Shared Technology and Facilitates in the Institute of Microbiology,CAS,and the Institute of Zoology,CAS.
