Bispecific antibodies combine specificities of two antibodies to simultaneously recognize/target different antigens or epitopes. In our preferred constructs, the Fab part of the antibody molecule is reconfigured to single-chain variable fragment (scFv), so that the antibody molecule is presented as two “extended heavy chains” covalently associated by interchain disulfide bonds. For each heavy chain, the N-terminal is scFv, the center part is CH2-CH3 domains of immunoglobulin γ1 chain, and at the C-terminal is a short peptide linker.
Here is an example of a bispecific antibody.
Validation of dual targeting ability of EGFR1/c-MET bispecific antibody (BsAb) by bridging ELISA. Anti-EGFR1/c-MET BsAb was first trapped by immoblized c-MET ECD-His antigen and then HRP labeled 2nd antigen, EGFRvIII ECD-HRP, was used as the detector for validation of the dual targeting ability of BsAb. Bridging ELISA results showing that anti-EGFR1/c-MET BsAb diaplays distinguished dual targeting ability, the EC50 is 0.56 nM.
Coating antigen: c-MET-ECD
Sample: serial diluted BsAb
Detection: 2nd antigen, EGFRvIII-HRP