Nanobody cocktails potently neutralize SARS-CoV-2 D614G N501Y variant and protect mice

Phillip Pymm, Amy Adair, Li Jin Chan, James P. Cooney, Francesca L. Mordant, Cody C. Allison, Ester Lopez, Ebene R. Haycroft, Matthew T. O'Neill, Li Lynn Tan, Melanie H. Dietrich, Damien Drew, Marcel Doerflinger, Michael A. Dengler, Nichollas E. Scott, Adam K. Wheatley, Nicholas A. Gherardin, Hariprasad Venugopal, Deborah Cromer, Miles P. DavenportRaelene Pickering, Dale I. Godfrey, Damian F.J. Purcell, Stephen J. Kent, Amy W. Chung, Kanta Subbarao, Marc Pellegrini, Alisa Glukhova, Wai Hong Tham

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45 Citations (Scopus)


Neutralizing antibodies are important for immunity against SARS-CoV-2 and as therapeutics for the prevention and treatment of COVID-19. Here, we identified high-affinity nanobodies from alpacas immunized with coronavirus spike and receptor-binding domains (RBD) that disrupted RBD engagement with the human receptor angiotensinconverting enzyme 2 (ACE2) and potently neutralized SARS-CoV-2. Epitope mapping, X-ray crystallography, and cryo-electron microscopy revealed two distinct antigenic sites and showed two neutralizing nanobodies from different epitope classes bound simultaneously to the spike trimer. Nanobody-Fc fusions of the four most potent nanobodies blocked ACE2 engagement with RBD variants present in human populations and potently neutralized both wild-type SARS-CoV-2 and the N501Y D614G variant at concentrations as low as 0.1 nM. Prophylactic administration of either single nanobody- Fc or as mixtures reduced viral loads by up to 104-fold in mice infected with the N501Y D614G SARS-CoV-2 virus. These results suggest a role for nanobody-Fc fusions as prophylactic agents against SARS-CoV-2.

Original languageEnglish
Article numbere2101918118
Number of pages12
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number19
Publication statusPublished - 11 May 2021


  • Antiviral therapeutics
  • Cryo-EM
  • Crystallography
  • Nanobodies
  • SARS-CoV-2

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