Depletion of NK cells reduced survival of mice and enhanced peripheral and CNS leukemia. NOD/SCID mice were intraperitoneally injected with either anti-Asialo GM1 (n = 13) or sterile PBS (n = 11) and then transplanted with 107 cells intravenously. (A) Confirmation of NK depletion by flow cytometry analysis of peripheral NK cells in blood samples from mice injected with anti-Asialo GM1 compared with PBS controls (P < .0001). (B) Kaplan-Meier survival curve depicting reduced survival of the NK-cell–depleted mice (P = .003, log-rank test). (C) Reduced weight of NK-cell–depleted mice on the day of euthanasia (P = .0005, t test). (D) Flow cytometry analysis of 018Z-cherry-positive cells in the (i) blood, (ii) BM, and (iii) brain. Data presented are from 3 independent experiments. Values are means ± SE. Statistical analysis was performed by t test. (E) Bioluminescent imaging of mice 27 days after transplantation with 018Z cells expressing the luciferase reporter: NK-cell–depleted mice (left) and PBS-injected mice (right). (F) Quantification of the images in E by Living Image Software. The leukemic load is represented as counts per minute (CPM; P = .004, t test).
