CD19xTCR DART molecule is highly purified and binds both of its target cells. (A) Schematic representation of the CD19xTCR DART molecule and a control DART molecule (4420xTCR) that binds TCR and fluorescein. (B) DART molecules were purified by affinity chromatography followed by SEC. Reducing SDS-PAGE and analytical SEC demonstrates proper assembly and a high degree of purity. The black trace is the CD19xTCR DART molecule and the gray trace is the 4420xTCR DART molecule. (C) Flow cytometric analyses of human PBMCs revealed bispecific binding of the CD19xTCR DART molecule (detected by biotinylated 1F5 mAb and streptavidin-APC) to both B cells (CD20) and T cells (CD3), whereas the 4420xTCR DART molecule displays binding only to T cells.