The CD3×CD123 DART enhances T-cell-mediated elimination of CD123-expressing cell lines in vitro. (A-C) Human T cells (2.5 × 10⁵ cells/well) were cultured with (A) A20^GFP or A20^GFP-CD123 cells, (B) K562^GFP or K562^GFP-CD123 cells, or (C) KG1 cells at a 10:1 ratio in the presence or absence of the indicated DARTs for 1 or 2 days. The absolute number of viable A20, K562, or KG1 targets were quantitated by flow cytometry, using 7-amino-actinomycin D (7-AAD), and cell survival is expressed relative to the PBS control. Each data point represents the average ± SD of 3 separate experiments, using different T-cell donors, where samples were analyzed in duplicate in each experiment. (D) Expression of CD123 on KG1 cells. (E-F) Human T cells were cultured with [⁵¹Cr]-labeled (E) A20^GFP or A20^GFP-CD123 cells or (F) K562^GFP or K562^GFP-CD123 at various E:T ratios in the presence of the indicated DARTs for 4 hours. *P < .05, **P < .01.