Lack of Treg cell activity from IL-7Rα^−/− mice. Suppressor populations were sorted for CD3, CD4, and CD25⁺ or CD25⁻. For each individual experiment, spleen cells were pooled from 2 wild-type mice and 10, 6, or 4 spleens from IL-7Rα^−/−, IL-7^−/−, or TSLPR^−/− mice, respectively. The top panel shows CD25⁺ Treg cells (▭) from various knockout mice mixed with CD25⁻ responders from wild-type mice, whereas the bottom panel shows both CD25⁺ Treg cells and CD25⁻ responders from the same knockout mice. WT Treg cells () are shown as a control at each mixture ratio.