While Takeuchi et al. describe a Th1 phenotype for CD4+CRTAM+ T cells, because of spontaneous differentiation to IFN-γ producing cells, CRTAM expression is required for IL-17 production and Th17 response during intestinal parasitic or bacterial infections, where Necl-2 is expressed by gut-resident DCs [34,84,85,86]. The gene discussed is CRTAM; the disease is bacterial infectious disease.