Vaccination following chemotherapy protects against leukemic rechallenge. (A-B) Mice were challenged with C1498 cells, and 24 hours later, three 3-mg doses of cytarabine were administered intraperitoneally 10 hours apart. On day 23, 1 group of chemotherapy-treated mice were administered the leukemia/α-GalCer vaccine, and symptom-free survival was monitored. (A,C) Surviving mice were rechallenged on day 45 with a fivefold increased dose of 5 × 10⁵ viable C1498 cells, and symptom-free survival was again followed. Symbols represent treatment groups: leukemia only (○), n = 10; cytarabine treatment (□), n = 19; and cytarabine plus α-GalCer vaccination (△), n = 20. (B-C) Represent 2 experiments. ****P < .0001 (log-rank Mantel-Cox test).