IL-18 is a proinflammatory cytokine. This cytokine can induce the IFN-gamma production of T cells. The combination of this cytokine and IL12 has been shown to inhibit IL4 dependent IgE and IgG1 production,and enhance IgG2a production of B cells. IL-18 binding protein (IL18BP) can specifically interact with this cytokine,and thus negatively regulate its biological activity.