Design and purification of CS1-NKG2D biAb by metal-affinity chromatography. Design and purification of CS1-NKG2D biAb by metal-affinity chromatography. A, Schematic diagram of the lentiviral construct for mammalian expression of CS1-NKG2D biAb in CHO-S cells. B, A typical profile of the protein eluted from immobilized metal-affinity chromatography column using stepwise imidazole gradient. C, SDS–PAGE for eluted protein. Lane 1: molecular weight marker (kDa); lane 2: protein lysate from mock-transduced CHO-S cells; lane 3: eluted control biAb (dashed arrow); lane 4: eluted CS1-NKG2D biAb (solid arrow). Results shown are representative of at least 10 independent experiments. Wing Keung Chan et al. Cancer Immunol Res 2018;6:776-787 ©2018 by American Association for Cancer Research