Structures of Foot-and-mouth Disease Virus with neutralizing antibodies derived from recovered natural host reveal a mechanism for cross-serotype neutralization.
He, Y., Li, K., Cao, Y., Sun, Z., Li, P., Bao, H., Wang, S., Zhu, G., Bai, X., Sun, P., Liu, X., Yang, C., Liu, Z., Lu, Z., Rao, Z., Lou, Z.(2021) PLoS Pathog 17: e1009507-e1009507
- PubMed: 33909694 
- DOI: https://doi.org/10.1371/journal.ppat.1009507
- Primary Citation of Related Structures:  
7D3K, 7D3L, 7D3M, 7D3R - PubMed Abstract: 
The development of a universal vaccine against foot-and-mouth disease virus (FMDV) is hindered by cross-serotype antigenic diversity and by a lack of knowledge regarding neutralization of the virus in natural hosts. In this study, we isolated serotype O-specific neutralizing antibodies (NAbs) (F145 and B77) from recovered natural bovine hosts by using the single B cell antibody isolation technique. We also identified a serotype O/A cross-reacting NAb (R50) and determined virus-NAb complex structures by cryo-electron microscopy at near-atomic resolution. F145 and B77 were shown to engage the capsid of FMDV-O near the icosahedral threefold axis, binding to the BC/HI-loop of VP2. In contrast, R50 engages the capsids of both FMDV-O and FMDV-A between the 2- and 5-fold axes and binds to the BC/EF/GH-loop of VP1 and to the GH-loop of VP3 from two adjacent protomers, revealing a previously unknown antigenic site. The cross-serotype neutralizing epitope recognized by R50 is highly conserved among serotype O/A. These findings help to elucidate FMDV neutralization by natural hosts and provide epitope information for the development of a universal vaccine for cross-serotype protection against FMDV.
Organizational Affiliation: 
State Key Laboratory of Medicinal Chemical Biology and Drug Discovery Center for Infectious Disease, College of Pharmacy, Nankai University, Tianjin, China.