Enhanced redirected immune cell killing and T-cell activation by the DART molecule. The CD19xTCR DART molecule (■), CD19xCD3 DART molecule (●), CD19xCD3 BiTE molecule (▾), and control DART molecule (♦) were evaluated for cytotoxicity against Raji B-cell lymphoma cells in the presence of either resting human PBMCs (A) or purified activated T cells (B), for induction of CD69 on purified T cells in the presence of Raji B-cell lymphoma cells on either the CD4⁺ T-cell subset (C) or the CD8⁺ T-cell subset (D), and for their ability to mediate IFNγ release (E) in the presence of Raji target cells and purified T cells. Cytotoxicity was detected using LDH release (A) or FACS-based analysis (B), with EC₅₀ values and maximum lysis determined using GraphPad Prism software. The data are representative of multiple independent experiments using independent human PBMC donors or purified T-cell populations.