KD035 was identified by panning of Dyax FAB‐310 phagemid library on immobilized human VEGFR2 (R&D systems) followed by affinity maturation using a light chain shuffling method. The constructs carrying KD035 antigen‐binding fragment (Fab) domain were cloned into the mammalian expression vector pBh1 (Dyax) and transiently expressed in human 293 Expi cells (Invitrogen). Fabs were purified from cell culture supernatant by passing it several times through a protein A Sepharose HP column (GE Healthcare) using a peristaltic pump for a period of 8 h and eluting with 1 M Glycine pH 2.0. The eluate was further purified by size exclusion chromatography (SEC) using a Superdex 75 increase (GE Healthcare) column.
The variable domain amino acid sequence of IMC‐1121B (which shares the amino acid sequence of ramucirumab as described in US 8057791 B2/EP 1916001 A2) was reverse‐translated into DNA sequences and optimized by using Integrated DNA Technologies tools. The synthesized genes of 1121 light chain and heavy chain variable domains were cloned into a mammalian expression vector pBh1 (Dyax). The plasmid DNA containing 1121 gene was transfected and expressed by using the FreeStyle™ MAX 293 Expression System (ThermoFisher Scientific) according to the manufacture instruction. The supernatant was harvested and purified by protein A (GE) with at least 95% monomer detected by SEC‐UPLC (Waters).
The variable domain amino acid sequence of IMC‐1121B (which shares the amino acid sequence of ramucirumab as described in US 8057791 B2/EP 1916001 A2) was reverse‐translated into DNA sequences and optimized by using Integrated DNA Technologies tools. The synthesized genes of 1121 light chain and heavy chain variable domains were cloned into a mammalian expression vector pBh1 (Dyax). The plasmid DNA containing 1121 gene was transfected and expressed by using the FreeStyle™ MAX 293 Expression System (ThermoFisher Scientific) according to the manufacture instruction. The supernatant was harvested and purified by protein A (GE) with at least 95% monomer detected by SEC‐UPLC (Waters).