Fig. 1.

CD16xCD33 BiKE enhances NK cell degranulation and cytokine release against CD33⁺ cell lines. a CD33 expression levels of the human acute promyelocytic leukemia cell line HL60/K562 (gray-dotted histogram), the human acute lymphoblastic cell line SEM (gray-dotted histogram), 6 primary ALL patients (light blue histogram) and three primary AML patients (red dotted histogram). b PBMCs from healthy donors were coated with 10 μg/mL of the CD16xCD33 BiKE alone or stimulated with IL-2, IL-15 or both of them and cocultured with CD33⁺ SEM targets. c Following depletion of CD33⁺ cells, PBMCs were stimulated overnight with IL2, coated with 10 µg/mL CD16xCD33 BiKE and cocultured with HL60 (n = 9) and SEM (n = 9) targets. NK cell degranulation, intracellular IFN-ɣ, TNF-α production and d cytotoxic lysis (PBMCs vs. HL60, n = 15, PBMCs vs. SEM, n = 10) were measured via flow cytometry. CFSE PI (propidium iodide) double positive cells were measured as cell death. Bars represent the mean expression from 9 healthy individuals c and 15/10 healthy individuals vs. HL60/SEM d, error bars represent standard error of the mean (SEM), statistical significance was determined by Mann–Whitney U test or paired t test (*p < 0.05, **p < 0.01, ***p < 0.001)