IL-18 potentiates the adjuvant properties of IL-12 in the induction of a strong Th1 type immune response against a recombinant antigen

Due to the synergistic effects of IL-12 and IL-18, and to their importance in establishing a Th1 type immune response, we investigated the potential of a combined administration of both cytokines as an adjuvant for recombinant antigens. As a model system, we used a schistosome T cell antigen recently identified in our group. By co-adsorption of this antigen on alum in the presence of IL-12 and IL-18, we demonstrate that IL-18 enhances the effects of IL-12 in inducing an antigen-specific Th1 type CD4+ T cell response as well as high titres of IgG1, IgG2a, and IgG2b antibodies.