Fig. 4: Cells with low IKAROS expression are resistant to CD19- and CD22-targeted therapies.

A Median IKAROS expression in IKAROS-degron models (KO1 and KO2) treated with DMSO (-ASU, n = 3) or 10 µM asunaprevir (+ASU, n = 3) for 7 days. Values were measured by flow cytometry and normalized to -ASU condition. N represents biological replicates from independent experiments. RFI relative fluorescence intensity. B, C CD19 (B) and CD22 (C) surface quantitation in IKAROS-degron models (KO1 and KO2) treated with DMSO (-ASU, n = 3) or 10 µM asunaprevir (+ASU, n = 3) for 7 days. N represents biological replicates from independent experiments. D–H IKAROS-degron models (KO1 and KO2) were treated with DMSO (-ASU) or 10 µM asunaprevir (+ASU) for 7 days. IKAROS-degron cells were washed out of DMSO or asunaprevir and co-cultured with blinatumomab-treated (D), 19.BBz (E), 19.28z (F), 22.BBz (G), and dual 19/22.BBz (H) CAR T cells at 1:1, 1:5, and 1:10 E:T ratio. B-ALL cell viability was measured at every 2 − 3 h interval via IncuCyte. GFP median values were normalized to 0 h condition. RFI relative fluorescence intensity. (*) denotes conditions in which both KO1 + ASU vs. KO1 -ASU and KO2 + ASU vs. KO2 -ASU comparisons were statically significant (p-values < 0.05). Please refer to the source data file for the exact p-value at each time point. Experiments in (D–H) were performed in triplicate with three different T-cell donors. Dots represent the mean value from two (A–C) or three (D–H) technical replicates. Bar plots in (A–C) show mean ± SEM. Curves in (D–H) show mean ± SEM. Statistical tests used were two-way ANOVA followed by Šidák’s multiple comparisons test, with a single pooled variance (A–C); and two-way ANOVA followed by Šidák’s multiple comparisons test (D–H).