Broad receptor tropism and immunogenicity of a clade 3 sarbecovirus.
Lee, J., Zepeda, S.K., Park, Y.J., Taylor, A.L., Quispe, J., Stewart, C., Leaf, E.M., Treichel, C., Corti, D., King, N.P., Starr, T.N., Veesler, D.(2023) Cell Host Microbe 31: 1961-1973.e11
- PubMed: 37989312 
- DOI: https://doi.org/10.1016/j.chom.2023.10.018
- Primary Citation of Related Structures:  
8U0T, 8U29 - PubMed Abstract: 
Although Rhinolophus bats harbor diverse clade 3 sarbecoviruses, the structural determinants of receptor tropism along with the antigenicity of their spike (S) glycoproteins remain uncharacterized. Here, we show that the African Rhinolophus bat clade 3 sarbecovirus PRD-0038 S has a broad angiotensin-converting enzyme 2 (ACE2) usage and that receptor-binding domain (RBD) mutations further expand receptor promiscuity and enable human ACE2 utilization. We determine a cryo-EM structure of the PRD-0038 RBD bound to Rhinolophus alcyone ACE2, explaining receptor tropism and highlighting differences with SARS-CoV-1 and SARS-CoV-2. Characterization of PRD-0038 S using cryo-EM and monoclonal antibody reactivity reveals its distinct antigenicity relative to SARS-CoV-2 and identifies PRD-0038 cross-neutralizing antibodies for pandemic preparedness. PRD-0038 S vaccination elicits greater titers of antibodies cross-reacting with vaccine-mismatched clade 2 and clade 1a sarbecoviruses compared with SARS-CoV-2 S due to broader antigenic targeting, motivating the inclusion of clade 3 antigens in next-generation vaccines for enhanced resilience to viral evolution.
Organizational Affiliation: 
Department of Biochemistry, University of Washington, Seattle, WA, USA.