To determine whether T. spiralis-induced Treg cells can prevent allergic airway inflammation in an OVA-alum asthma mouse model, we injected mice with CD4+Foxp3+ T cells isolated from T. spiralis-infected [Inf(+)Foxp3+] or uninfected [Inf(-)Foxp3+] mice and evaluated allergic inflammation responses after OVA sensitization and challenge (Fig. 1B, Stage I). Here, FOXP3 is linked to asthma.