MPL synergizes with ADX40 to increase immune responses against A20-Id and retards tumor progression in a therapeutic setting. (A) Anti-Id end-point titer after boost shows enhancement after immunization with ADX40-A20 and significant further enhancement when co-immunized with MPL (mean ± SD; n = 35). (B-C) Kaplan-Meier survival curve showing significantly increased median survival of mice given the combination treatment to ADX40-A20 vaccine alone (B; n = 45) and significantly lower tumor burden (C). * P < .05; *** P < .0005. (D) In a therapeutic setting, mice were challenged with A20 cells on day 0, followed by a primary vaccination on day 1 and a booster vaccination on day 8. (E) ADX40-A20 + MPL vaccination after challenge resulted in significantly slower tumor growth (gray line) compared with PBS (black line). *P < .05 by Student t test. (F) Graph showing the 4.5-day increase in median survival of ADX40-A20–vaccinated mice (gray line) compared with PBS–injected mice (black line); however, this was not significant. Figure shows pooled data from 2 independent experiments (n = 20).