Broad‐Spectrum Engineered Multivalent Nanobodies Against SARS‐CoV‐1/2

SARS‐CoV‐2 Omicron sublineages escape most preclinical/clinical neutralizing antibodies in development, suggesting that previously employed antibody screening strategies are not well suited to counteract the rapid mutation of SARS‐CoV‐2. Therefore, there is an urgent need to screen better broad‐spectrum neutralizing antibody. In this study, a comprehensive approach to design broad‐spectrum inhibitors against both SARS‐CoV‐1 and SARS‐CoV‐2 by leveraging the structural diversity of nanobodies is proposed. This includes the de novo design of a fully human nanobody library and the camel immunization‐based nanobody library, both targeting conserved epitopes, as well as the development of multivalent nanobodies that bind nonoverlapping epitopes. The results show that trivale B11‐E8‐F3, three nanobodies joined tandemly in trivalent form, have the broadest spectrum and efficient neutralization activity, which spans from SARS‐CoV‐1 to SARS‐CoV‐2 variants. It is also demonstrated that B11‐E8‐F3 has a very prominent preventive and some therapeutic effect in animal models of three authentic viruses. Therefore, B11‐E8‐F3 has an outstanding advantage in preventing SARS‐CoV‐1/SARS‐CoV‐2 infections, especially in immunocompromised populations or elderly people with high‐risk comorbidities. This study presents the design and development of multivalent nanobodies targeting conserved epitopes of SARS‐CoV‐1 and SARS‐CoV‐2. The trivalent nanobody B11‐E8‐F3 exhibits broad‐spectrum neutralization against SARS‐CoV‐1 and multiple SARS‐CoV‐2 variants, including Omicron sublineages, and demonstrates significant preventive and therapeutic efficacy in animal models.