Fig. 1

Construction and generation of the bispecific antibody. A Schematic diagram of the molecular configurations of IgG-like bsAb Bi-Nab. B Schematic presentation of the IgG-like bispecific antibody Bi-Nab. The variable regions of the heavy and light chains of 32C7 or 35B5 are color-coded (the variable light chain and heavy chain of 32C7 are colored purple and light blue, respectively; the variable light chain and heavy chain of 35B5 are colored green and light red, respectively); human IgG1 Fc is colored gray. The 3 × G4S and 5 × G4S linkers were used to form the scFv 32C7-35B5. C The equal mass of Bi-Nab or two parental mAbs was analyzed by SDS‒PAGE under reducing conditions with DTT. H and L denote the heavy and light chains of parental mAbs, respectively. The molecular weight of the Bi-Nab monomer is 90 kD. Antibodies were expressed in ExpiCHO-S cells and captured on Protein-A affinity resin. M, molecular weight standard. D Nonreduced SDS‒PAGE analysis of Bi-Nab or two parental mAbs. The antibodies were analyzed under direct affinity elution conditions without DTT, and three independent experiments were performed with the same results