Figure 1. Newly released CD4⁺ T cells from the atrophied thymus acquired an activated immune cell phenotype.

F-cKO and FF-Ctr (fx/fx-uCreER^T and fx/fx mice, respectively) were crossed with Rag2-GFP mice and then FoxN1^fx/fx deletion was induced in 6-week-old adult mice with i.p. injected tamoxifen (TM). 14 days later, peripheral splenocytes were freshly isolated and stained with CD4, CD44, and Ki67 antibodies, and CD4⁺GFP⁺ cells were defined as CD4⁺ RTEs. (A) Representative dot plots show CD44^hiKi67⁺ cell gates (red boxes) in CD4⁺ RTEs from F-cKO (top panels) and FF-Ctr control (bottom panels) mice. (B) Representative histograms of CD44^hi (left panels) and Ki67⁺ (right panels) in CD4⁺ RTEs from F-cKO (top panels) and FF-Ctr control (bottom panels) mice. (C) Summarized results of % CD44^hi, Ki67⁺, and CD44^hiKi67⁺ double positive cells in CD4⁺ RTEs (from left to right panels). A Student t-test was used to determine statistical significance between groups. All data are expressed as mean ± SEM. Data are pooled from at least three independent experiments (n = animal numbers).