Fig. 2: Identification of VH domains that bind Spike-RBD at two unique epitopes by phage display.
From: Bi-paratopic and multivalent VH domains block ACE2 binding and neutralize SARS-CoV-2
a, Diagram illustrating the phage selection strategy to isolate VH-phage that bind at the ACE2 binding interface. Red indicates clearance of the phage pool by the Spike-RBD-Fc/ACE2-Fc complex; green indicates positive selection against Spike-RBD-Fc alone. To increase stringency, successively lower concentrations of Spike-RBD-Fc were used and, after four rounds of selection, individual phage clones were analyzed by phage ELISA. b–d, Bio-layer interferometry (BLI) of VH A01 (b), VH B01 (c) and VH B02 (d) against Spike-RBD. e–g, BLI-based epitope binning of VH A01 and VH B01 (e), VH A01 and VH B02 (f) and VH B01 and VH B02 (g). The antigen loaded onto the sensor tip was Spike-RBD. h, Diagram of the two different epitope bins targeted by VH domains.
