IL4 and malaria: Interleukin-4 (IL-4) is a major mediator for the induction of the immune response against S. mansoni. Therefore, we examined the impact of IFN-γ and IL-4 on liver-stage malaria parasite burden using IFN-γ-deficient (IFN-γ-/-) and IL-4-deficient (IL-4-/-) mice.