Type I IFNs induce ICSBP expression and rescue mice from a BCR-ABL–induced leukemia. RT-PCR and Q-RT-PCR showing the expression of ICSBP before and at different time points after IFN alpha or IFN beta treatment (10⁴ U/mL unless otherwise specified) in (A) parental BaF3 cells (n = 3 ± standard deviation); (B) BaF3 cells transformed with BCR-ABL; (C) parental and BCR-ABL transformed 32D cells; and (D) healthy human peripheral blood mononuclear cells (hPBMCs) and human CML cell lines AR230 and K562. Similar results were obtained from hPBMCs from 3 different healthy donors. (E) Cell-autonomous protection against leukemia conferred by ICSBP and type I IFNs. Survival curves of 6- to 9-week-old Balb/c mice injected with 10⁶ BaF3 cells expressing the indicated cDNAs. At least 2 experiments per condition were performed, each containing 5 to 10 mice for each cell type. (F) Non–cell-autonomous protection against leukemia conferred by ICSBP and type I IFNs. Survival curves for 6- to 9-week-old Balb/c mice injected with 0.5 × 10⁶ BaF3 cells separately expressing indicated cDNAs. At least 2 experiments per condition were performed, each containing 5 to 10 mice for each cell type.