Infection status likely determines the importance of TLR signaling in controlling Treg cell frequencies; TLR2-deficient mice have equal proportions of Foxp3+CD4+ cells at the MLN site at steady state (52), yet during the H. polygyrus infections performed in this study, and during Candida albicans infection (53), proportions are reduced, compared with wild-type mice. Here, FOXP3 is linked to infection.