Fig A-H: 2.5 × 106 cells MOLM-13 cells/mouse were engrafted in NSG mice. Mice were treated with 200 μL of 220 μM of A192 (n=4) or α-CD99-A192 (n=4) on day 7, 10, 13 and 16 post engraftment and euthanized on day 17. A) Spleen images and B) Spleens weights were measured upon euthanization. Spleens of mice treated with α-CD99-A192 weighed significantly less compared with the A192 treated mice (113 vs. 180 mg, p<0.001). Leukemia engraftment was measured using human CD45 (huCD45) antibody by flow cytometry in the C-D) peripheral blood (%huCD45: 6 vs. 22%, p<0.001), E-F) bone marrow (29 vs. 53%, p<0.0001) and G-H) spleen (%huCD45: 5 vs. 13%, p<.0001). I) 2.5 × 106 MOLM-13 cells/mouse were engrafted in NSG mice and treated with 200 μL of 220 μM A192 (n=7) or α-CD99-A192 on Day 7, 10, 13 and 16 post engraftment and survival was recorded. Kaplan Meier survival analysis showed that mice in the α-CD99-A192 treatment group survived significantly longer than mice in the A192 group (median survival: 37vs. 28 Days, p<0.0001).