TNFα produced by DNTs, upon encountering sensitive AML, renders DNT-resistant AML susceptible to DNT killing. (A) DNTs were cocultured with DNT-resistant KG-1a in the presence or absence of DNT-susceptible AML (MV4-11 or OCI-AML3) at a 2:1:1 (DNT: KG-1a: DNT-susceptible AML) ratio for 24 hours. Specific killing of KG-1a was measured by flow cytometry. The experiments were done in triplicates, and the data shown are representative of 2 independent experiments. (B-C) MV4-11 were cultured with or without DNTs in the top compartment of a transwell. KG-1a alone or cocultured with DNTs were placed in the bottom compartment of the transwell. Cells were then incubated for 2 days as shown in the schematic (B). Specific killing of KG-1a cells in the bottom compartment was measured and compared between MV4-11 and MV4-11 + DNT conditions (C). The experiments were done in triplicates. The data shown are representative of 2 independent experiments. (D-E) DNT-resistant AML, KG-1a (D) or OCI-AML3^CD64KO (E), were incubated alone or with DNT-susceptible AML, MV4-11 (D) or OCI-AML3^WT (E), and DNTs in the presence of anti-TNFα blocking antibody (10 μg/mL) or isotype control for 2 days. Antibodies were added on day 0 and day 1 of the cocultures. Specific killing of DNT-resistant AML cells was measured by flow cytometry. The experiments were done in triplicates. The data shown are representative of 2 independent experiments. Student t test and 1-way/2-way ANOVA were used. ∗P < .05; ∗∗∗P < .001. ns, nonsignificant.