TNF and infection: Studies have shown that during the early period of schistosome infection in mice, the induction of a T-helper cell type I (Th1)-dominated immune response against schistosome infection is characterized by increased levels of interferon-γ (IFN-γ) and tumor necrosis factor α (TNF-α), and that the host immune response shifts to a Th2-dominant immune response 4–6 weeks after infection which is characterized by increased expression levels of several interleukins (ILs), including IL-4, IL-13 and IL-12 [1].