CpG ODN treatment improves survival of mice bearing established ALL. (A) NOD/SCID mice bearing A199 primary ALL cells were injected weekly with CpG ODN (•) or PBS (▪), starting 1 day after human leukemia cells were first detected in peripheral blood (day 0). Peripheral leukemia burden was then measured each week until the animals were killed. (B) The leukemia burden in organs of CpG ODN- (dark gray bars) or PBS-treated (light gray bars) mice (from panel A) was measured at death (4 mice/group). *P < .05.