Bi-paratopic and multivalent VH domains block ACE2 binding and neutralize SARS-CoV-2.

Neutralizing agents against SARS-CoV-2 are urgently needed for the treatment and prophylaxis of COVID-19. Here, we present a strategy to rapidly identify and assemble synthetic human variable heavy (VH) domains toward neutralizing epitopes. We constructed a VH-phage library and targeted the angiotensin-converting enzyme 2 (ACE2) binding interface of the SARS-CoV-2 ...
Spike receptor-binding domain (Spike-RBD). Using a masked selection approach, we identified VH binders to two non-overlapping epitopes and further assembled these into multivalent and bi-paratopic formats. These VH constructs showed increased affinity to Spike (up to 600-fold) and neutralization potency (up to 1,400-fold) on pseudotyped SARS-CoV-2 virus when compared to standalone VH domains. The most potent binder, a trivalent VH, neutralized authentic SARS-CoV-2 with a half-maximal inhibitory concentration (IC50) of 4.0?nM (180?ng?ml-1). A cryo-EM structure of the trivalent VH bound to Spike shows each VH domain engaging an RBD at the ACE2 binding site, confirming our original design strategy.
Mesh Terms:
Angiotensin-Converting Enzyme 2, Animals, Antibodies, Neutralizing, Antibodies, Viral, Binding Sites, Antibody, Chlorocebus aethiops, Cryoelectron Microscopy, HEK293 Cells, Humans, Models, Molecular, Peptide Library, Protein Binding, Protein Conformation, alpha-Helical, Protein Conformation, beta-Strand, Protein Interaction Domains and Motifs, SARS-CoV-2, Single-Chain Antibodies, Spike Glycoprotein, Coronavirus, Vero Cells
Nat Chem Biol
Date: Jan. 01, 2021
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