Figure 3.

Engineered protein formats that have been applied to generate hapten‐binding bispecific antibodies. (A) 2 + 2 ‘Morrison‐Type’ bsAbs which are nowadays in most cases stabilized by interchain disulfides (indicated in yellow) in the attached scFvs. (B) 2 + 1 IgG‐derived bsAbs with knob‐into‐hole Fc regions and disulfide‐stabilized VH and VL, respectively, at the C‐termini of CH3. (C) Fab‐derived bsAb format that has a disulfide‐stabilized Fv attached to the C‐termini of CH1 or CL, respectively. (D) CrossMabs generate the desired H‐chain heterodimers via knob‐into‐hole mutations placed into their constant regions. They contain in addition one designed domain‐exchanged Fab arm to assure correct light chain pairing.