Figure 5. NK cells induced by in vivo IL pre-activation and re-stimulation prolongs survival of leukemia mice.
(A) Rag1KO B6 (CD45.2+) mice were divided into three groups: (●) one group of mice received neither IL pre-activation nor re-stimulation as vacant control; (■) one group of mice received IL pre-activation only as negative control; (□) the experimental group of mice received both pre-activation (4.5 μg/mouse IL-12, 5.5 μg/mouse IL-15, and 22 ng/mouse IL-18) and re-stimulation (5 μg/mouse IL-12 and 8 μg/mouse IL-15). After IL stimulation, all mice were inoculated with 1 × 104 Notch1-T-ALL leukemia cells. Kaplan-Meier analysis was performed to assess survival of mice (median survival time: 21 days for the vacant control group, 37 days for the negative control group, and 73 days for the IL re-stimulation group (n = 10 per group, p < 0.05). (B) Mice received both IL pre-activation and re-stimulation as above were inoculated with 1 × 105, 2 × 105, 5 × 105, and 1 × 106 Notch1-T-ALL cells, respectively. Mice received no IL stimulation as described above as vacant control were inoculated with 1 × 104 leukemia cells. Kaplan-Meier analysis was performed to assess survival of mice. Median survival time: 21 days for control (□), 64 days for 1 × 105 cells (○), 46 days for 2 × 105 cells (▼), 31 days for 5 × 105 cells (∆), or 19 days for 1 × 106 cells (■), respectively (n = 10 per group, p < 0.05 for comparison between 1 − 5 × 105 cells vs. control, p > 0.05 for 1 × 106 cells vs. control).