Infection with pathogens that induce TH1 CD4+ lymphocytes and secrete interferon gamma (IFNg) and interleukin-2 (IL-2) can be compared to induction of the TH2 response following schistosome infection or exposure to parasite eggs or egg antigen resulting in the production of IL-4, IL-5, and IL-13. The gene discussed is IFNG; the disease is infection.