IL-7R expression is a biomarker of murine T-ALL cells with LIC potential. (A) Immunoblot analysis of STAT5 and AKT activation in a representative primary murine T-ALL (moT-ALL1), generated as in Figure 3A, and stimulated with IL-7 for the indicated times. α-Tubulin expression is shown as loading control. Molecular weight (KDa) is indicated on the left. (B) Total numbers of primary murine T-ALL cells (moT-ALL1 and moT-ALL2), generated as in Figure 3A, and cultured for the indicated days onto OP9-GFP cells in the presence or absence of IL-7. Data from a representative experiment of 3 are shown. (C) IL-7R expression levels of primary murine T-ALL cells (moT-ALL4) analyzed by flow cytometry immediately after isolation from the spleen of diseased mice in Figure 3A or after serial transplantation and spleen engraftment into consecutive NSG-immunodeficient mice (1st and 2nd grafts). Mean fluorescence intensity (MFI) values (mean ± SEM) from 3 to 12 mice are shown. (D) Kaplan-Meier survival curves of NSG mice serially transplanted with primary murine moT-ALL4 cells as in (C). **P < .01, ***P < .001.