Treg self-sufficiency for IL-2 drives dose-dependent expansion. (A) Representative histograms of IL-2 expression in WT or Foxp3^creRosa^IL-2 splenocytes incubated with BrefA for 4 h to prevent cytokine secretion. (B) Splenic cellularity of Foxp3^cre/wtRosa^IL-2, Foxp3^cre/YRosa^IL-2, or littermate controls. n = 5–15. (C) Survival analysis. n = 11–23. (D) tSNE representation of high-parameter flow cytometry data from viable splenocytes (left). FlowSOM clusters annotated based on differential expression of key markers. Dendrogram showing comparative similarity calculated using cross-entropy distributions from tSNE (right). (E) Correlation between clusters in D. WT:Rosa^IL-2 indicates whether correlation is higher or lower in WT relative to Foxp3^cre/wt or Foxp3^cre/Y Rosa^IL-2. (F) Frequency of splenic CD8⁺ Tconv, CD4⁺ Tconv, and CD4⁺ Treg cells. n = 5–15. (G) Frequency of Foxp3⁺ cells among total CD4⁺ T cells. n = 5–15. (H) Uniform Manifold Approximation and Projection (UMAP) representation of high-parameter flow cytometry data of Foxp3^cre-expressing Tregs from Foxp3^cre/wtRosa^wt or Foxp3^cre/wtRosa^IL-2 mice. FlowSOM clusters annotated based on differential expression of key markers. D value represents cross-entropy distance between samples. Data are pooled from at least two independent experiments. Significance was tested by one-way ANOVA (B, F, and G), Mantel–Cox log-rank test (C), multiple Kolmogorov–Smirnov test with Holm correction (D), or two-sample Kolmogorov–Smirnov test (H).