Differentiation of Th cell subsets influences one another. During nematode infection, Th2 immune response becomes dominant, therefore Th1 and Th17 cells are considered to play only limited role against nematode infection. In order to investigate the role of Th17 cells in the protection against intestinal nematode infection, we infected mice lacking Th2 immune response (STAT6 KO) with Trichinella spiralis. IFN-γ deficiency resulted in Th17 cell differentiation (Immunol Lett 127, 55-9, 2009), therefore STAT6 and IFN-γ receptor (GR) double KO (DKO) mice were compared to STAT6 KO littermates. Recovery of muscle larvae in DKO mice infected with muscle larvae were decreased compared to STAT6 KO mice. IL-17 production from the mesenteric lymph nodes was higher in DKO than in STAT6 KO mice. Because macrophages are considered other important cells in the intestine of mice lacking Th2 immune response, cytokine produced by macrophages were investigated after stimulation with the nematode. Newborn larvae and adult worms were co-incubated with macrophages from WT and STAT6 KO mice. Production of IL-10, MCP-1 and MIP-1β was comparable in both mice, although Il-6 and TNF-α production was increased. Relation between pathological change in the small intestine during the infection and cytokine production were now being investigated.