Fig. 3: scFv-based ReconnAbs tether ACE2 to cross-reactive, non-neutralizing antibodies.
From: Converting non-neutralizing SARS-CoV-2 antibodies into broad-spectrum inhibitors
a, A schematic of an scFv-based ReconnAb protein before and after TEV cleavage. Estimated molecular weights of cleavage products are shown beneath both. b, Schematic of ReconnAb activity and the dependence on the tether. The scFV binds to a conserved site, and then ACE2 interacts with the RBD. Upon TEV cleavage, the ACE2 has lower apparent affinity and does not bind the RBD (right). Conserved sites are shown as teal; the remainder of the spike monomers are shown as tints of brown and ACE2 as dark brown. c, SDS-PAGE demonstrates that ReconnAbs are readily cleaved by TEV. 1. Full-length ReconnAb; 2. ACE2; 3. scFv. d, BLI binding of uncleaved and TEV-cleaved ReconnAbs to either SARS-CoV-2 spike (left) or SARS-CoV-1 spike (right) shows a reduction in binding upon TEV cleavage. e, BLI binding of hFc-ACE2 to SARS-CoV-2 spike, which has been pre-associated with ReconnAbs either uncleaved (solid lines) or cleaved (hashed lines), shows that TEV-cleaved ReconnAbs do not compete with hFc-ACE2 binding. Binding of hFc-ACE2 without competitor is shown on the right (dotted line).
