Fig. 1: Design and characterization of bsAbs.
From: An engineered bispecific human monoclonal antibody against SARS-CoV-2
a–d, Formats of the bsAbs designed. The formats of bsAb13 (a) and bsAb14 (b) are DVD-Ig, whereas bsAb15 (c) and bsAb16 (d) are IgG-ScFv. Antibody domains are colored according to their architecture (green, constant domain of the heavy chain; light green, constant domain of the light chain; deep pink, variable heavy chain of B38; light pink, variable light chain of B38; yellow, variable heavy chain of H4; and light yellow, variable light chain of H4). e–h, Competitive binding of parental mAbs and bsAbs. Biotinylated antigen (SARS-CoV-2 RBD) was immobilized on streptavidin sensors and then saturated with B38 or H4, followed by bsAbs. i–l, Binding affinity analysis of bsAbs to SARS-CoV-2 RBD. bsAbs were immobilized on protein A chips and tested for real-time association and dissociation of the RBD. The equilibrium dissociation constant (KD) was calculated using the association constant (Ka) and dissociation constant (Kd) with a two-state reaction model. The solid blue line is the actual operation curve, and the dashed red line is the fitted curve. Each experiment was repeated twice, and the results shown are means ± s.d. See also Extended Data Fig. 1.
