161519 TriKE amplifies NK cell function in autologous and allogeneic in vitro settings. PBMCs obtained from CLL patients (n = 5) were cultured with Raji target cell line (2:1 effector-to-target ratio) for a 4-hour period in the presence of treatment conditions at 30 nM (for everything but IL-15 [used at 0.3 nM]). NK cells were determined by CD56⁺/CD3⁻ expression and degranulation, and IFNγ production was assessed. (A) Pooled data showing CD107a expression on NK cells from CLL patient samples incubated in the presence of Raji targets. (B) Pooled data showing intracellular IFNγ expression on NK cells from CLL patient samples incubated in the presence of Raji targets. To evaluate 161519 TriKE in an allogeneic setting, enriched allogeneic NK cells from healthy donors were incubated with noted molecules (30 nM for everything but IL-15 [used at 0.3 nM]) for 18 hours, washed, and then placed in culture alone or cocultured with CellTrace-labeled CLL patient cells (2:1 effector-to-target ratio) for a 4-hour period with outlined treatment conditions added again at a 30 nM (for everything but IL-15 [used at 0.3 nM]) concentration (n = 17; 2 experiments with 2-3 NK donors against 3-4 CLL targets). CellTrace dye was used to be able to distinguish healthy donor–enriched NK cells from CLL patient NK cells. (C) CD107a expression on CellTrace⁻ NK cells cultured with CLL patient cells. (D) Intracellular IFNγ production on CellTrace⁻ NK cells cultured with CLL patient cells. One-way ANOVA with repeated measures was used to calculate differences against the 161519 group. Error bars indicate the mean ± standard error of the mean. Statistical significance are determined as *P < .05, **P < .01, ***P < .001, and ****P < .0001.