SARS-CoV-2 remains a global threat to human health particularly as escape mutants emerge. There is an unmet need for effective treatments against COVID-19 for which neutralizing single domain antibodies (nanobodies) have significant potential. Their small size and stability mean that nanobodies are compatible with respiratory administration. We report four nanobodies (C5, H3, C1, F2) engineered as homotrimers with pmolar affinity for the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. Crystal structures show C5 and H3 overlap the ACE2 epitope, whilst C1 and F2 bind to a different epitope. Cryo Electron Microscopy shows C5 binding results in an all down arrangement of the Spike protein. C1, H3 and C5 all neutralize the Victoria strain, and the highly transmissible Alpha (B.1.1.7 first identified in Kent, UK) strain and C1 also neutralizes the Beta (B.1.35, first identified in South Africa). Administration of C5-trimer via the respiratory route showed potent therapeutic efficacy in the Syrian hamster model of COVID-19 and separately, effective prophylaxis. The molecule was similarly potent by intraperitoneal injection.
Bibliographical noteFunding Information: This work was supported by the Rosalind Franklin Institute, funding delivery partner EPSRC. PPUK is funded by the Rosalind Franklin Institute EPSRC grant no. EP/ S025243/1. J.H.N., A.L.B., P.J.H., M.W. and P.W. are supported by Wellcome Trust (100209/Z/12/Z). J.H. is supported by the EPA Cephalosporin Fund. X-ray data were obtained using Diamond Light Source COVID-19 Rapid Access time on Beamline I03, I04 and I24 (proposal MX27031). The core virus neutralisation facility is supported by gifts to the Oxford COVID-19 Research Response Fund. EM results were obtained at the national EM facility at Diamond, eBIC, through rapid access proposal BI27051. Work at the University of Liverpool is supported by MRC grant MR/W005611/1, G2P-UK; A National Virology Consortium to address phenotypic consequences of SARSCoV-2 genomic variation (JPS and JAH) and by the US Food and Drug Administration (USA) 75F40120C00085, Characterisation of severe coronavirus infection in humans and model systems for medical countermeasure development and evaluation (JAH). We wish to thank the laboratory staff of the Histology Laboratory, Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, and the laboratory staff of the Pathology Laboratory and Biological Investigations Group Public Health England, Porton Down for excellent technical support. We are grateful to Josep Monné Rodriguez for his assistance in the design of the apps for the morphometric assessment. We thank Tomas Mal-inauskas (Oxford University) and colleagues at the CMB (Oxford University) for assistance with protein production and Professor Gary Stephens, Barney Jones and Hong Lin (Reading University) for expertise in llama immunisation.
Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
Publisher Copyright: © The Author(s) 2021
Citation: Huo, J., Mikolajek, H., Le Bas, A. et al. A potent SARS-CoV-2 neutralising nanobody shows therapeutic efficacy in the Syrian golden hamster model of COVID-19. Nat Commun 12, 5469 (2021).