Purification of crude BsAb by size-exclusion column chromatography. (A) UV profile of Traut’s-SMCC-crosslinked BsAb running in Superdex 200 10/300 GL. (B) Native electrophoresis of Fractions B6 to C4. Equal proportions (2%) of each fraction were loaded in each well. (C) Native electrophoresis of anti-CD3/anti-HER2 equal molar mixture (mix), crude crosslinking product (crude) and purified BsAb (purified).