It has been proposed that NOD2-/- mice were highly sensitive to Toxoplasma gondii infection and that transfer of naive CD4+CD45RBhigh Nod2 deficient T cells into Rag1-/- recipient mice failed to induce colitis due to a T cell intrinsic defect in proliferation and Th1 differentiation [20]. This evidence concerns the gene RAG1 and colitis.