AML-lysate–pulsed DC vaccines or Flt3L injections mediate potent antileukemia effect when given prior to a lethal dose of AML cells in nontransplanted animals.
Cohorts of naive B6 mice (n = 8-10) received either 3 weekly doses of tumor-lysate–pulsed DCs (beginning on day −42 or −21), or 21 daily subcutaneous Flt3L (30 μg per dose) injections (days −10 to +11), or no treatment (controls) followed by a lethal leukemia dose (105 cells per mouse) on day 0. Eight to 10 mice per group were analyzed. (A) A Kaplan-Meier survival plot shows days post–lethal C1498 challenge (day 0) on the x-axis and the proportion of mice surviving on the y-axis. The actuarial survival rate of either DC-vaccinated or Flt3L-treated recipients was significantly higher (P < .001) than the control animals. (B) On day 0, 2 mice in each group were killed for splenic C1498 leukemia-reactive CTLP frequency estimation. The mean total splenic anti-AML CTLP number ± SD is shown on the y-axis for each of the 3 groups. A significant increase in CTLP number was present in both DC-vaccinated (P = .01) and Flt3L-treated (P = .03) animals, although DC-treated mice showed a significantly higher CTLP expansion than mice receiving Flt3L (P = .02).
