Moreover, as shown in the current study, IL-17ACre– or Rag1Cre-mediated excision of Tbx21 in cells once expressing IL-17 or Rag1 had no effect on the number of IL-17/IFN-γ– double-producing cells, nor on the severity of immunopathology in H. hepaticus colitis. The gene discussed is RAG1; the disease is colitis.