HP and infection: As expected, the majority (∼98%) of cells expressing Foxp3YFP were marked with FP635 (Foxp3FATE; Fig. 4 B, middle; Miyao et al., 2012), indicating that they were currently (Foxp3YFP+) and had in the past (Foxp3FATE+) expressed Foxp3. Strikingly, during secondary infection with H. polygyrus, a substantial proportion (up to 20%) of Il4GFP+ Th2 cells were Foxp3YFP−Foxp3FATE+ (Fig. 4 B, right), with significantly higher proportions in Hp 2° relative to Hp 1° mice (Fig. 4 C).