IFN injection into Ubp43-deficient BCR-ABL⁺ recipient mice reduces the leukemic cell percentage. Recipients of BCR-ABL–transduced UBP43⁺ (n = 2) or UBP43⁻ (n = 5) were injected subcutaneously with 18 000 units/day mIFNβ beginning at day 17 or day 28, respectively. The graph is a plot of the percentage change over time in total donor cells (CD45.2⁺) and BCR-ABL–positive donor cells (EGFP⁺) from the start date of the injection (day 0). UBP43⁺ recipient mice rapidly succumbed to BCR-ABL–induced leukemia, whereas UBP43⁻ recipients showed a decrease in the donor cell numbers up to a maximum of approximately 50% at day 10.