Analysis of the bsAbs produced in Expi293™ mammalian cells by SDS/PAGE. (A) 3 independent transfections used to produce a bsAb with an WT T427 Fab arm and an engineered anti CD24 Fab arm (the anti CD24 antibody is a humanized IgG1-Kappa). Me, conditioned medium of untransfected cells; T1, T2, T3 are day 6 conditioned media from 3 transfections. K, KappaSelect unbound fraction; E1, E2, E3 are the bsAbs eluted from the KappaSelect column. Er, Erbitux (used as a full-size IgG protein marker); (B) bsAbs identical to those described in Table 3 above. 2.5 µg of each of the purified antibodies were separated on a 10% SDS-PAGE under non-reducing conditions and visualized using GelCode Blue™ staining.