Specific recognition and killing of tumor cells by clone no. 34 BiTE. Recognition and cytolytic activity of the naturally presented WT1 RMF/A2 complex on the tumor cell surface by the ESK2 clone no. 18 and no. 34 BiTEs were probed. (A) MAC-1 T-cell lymphoma, (B) JMN mesothelioma, or (C) SW-620 colon cancer cell lines were incubated with PBMCs at an effector-to-target (E:T) ratio of 20:1, in the presence or absence of BiTEs and control BiTEs at the indicated concentrations overnight, and the cytotoxicity was measured by BLI. (D) BV173 CLL, (E) SET-2 AML, (F) or HL-60 AML cell lines were incubated with PBMCs at an E:T ratio of 20:1, in the presence or absence of clone no. 34 BiTE or control at the concentrations of 1 μg/mL, 0.3 μg/mL, or 0.1 μg/mL for 5 hours and the cytotoxicity was measured using a 51Cr-release assay. The mean shown is the average of triplicate microwells ± standard deviation. The data are representative of 10 experiments. The effector cells were used from several different donors; whereas differences among the experimental groups were similar, the baselines were variable among the individuals; therefore, only representative data are shown.
