Numerous studies indicate an important role for innate immune-derived IFNγ in the induction of protective CD4+ T-cell responses to infections.16–19 We have previously shown that the innate immune response to AS01, but not to AS04 or emulsion-based adjuvants, is characterized by IFNγ-related cytokine production in the dLN.7, 20, 21 To confirm the synergistic induction of IFNγ by MPL and QS-21 in AS01, we analyzed the levels of this cytokine in the dLN after immunization with HBs adjuvanted with AS01 or its components. Here, IFNG is linked to infection.