FOXP3 and colitis: Foxp3+ Treg cells isolated from the mesenteric lymph node of H. polygyrus-infected mice were adoptively transferred into RAG−/− mice and conferred protection from piroxicam-induced colitis, whereas Foxp3+ Treg cells from uninfected animals did not (15, 66); these data correlate with the known potency of H. polygyrus to activate the host Treg cell compartment (159).