IL-7 therapy induces stronger proliferation of CD4⁺_SPT compared with CD4⁺_PERI. (A) Schematic representation of the experimental design where CFSE-labeled CD45.1⁺CD4⁺CD8⁻ (CD4⁺_SPT) and CD45.1⁺CD4⁻CD8⁺ (CD8⁺_SPT) thymocytes enriched from the thymus of CD45.1⁺B6SJL mice were mixed at a ratio of 1:1 prior to their adoptive transfer into CD45.2⁺C57BL6 recipients. Recipient mice were then treated daily with PBS (vehicle) or rhIL-7 for 6 days. (B) Representative flow cytometric analysis of transferred thymocytes CD45.1⁺CD4⁺CD8⁻ and CD45.1⁺CD4⁻CD8⁺ found in the LN of PBS- and IL-7–treated mice. (C) Graphic summary of the mean percentage ± standard error of proliferating CD4⁺_SPT and CD8⁺_SPT in response to IL-7 therapy according to CFSE dilution. (D-E) Graphical mean of the absolute number of CD4⁺_SPT and CD8⁺_SPT found in LN and spleen of PBS- and IL-7–treated recipients. Inlets show fold expansion of CD4⁺_SPT and CD8⁺_SPT in LN and spleen of IL-7 vs PBS-treated animals. (F) Comparison of CFSE-labeled CD4⁺_SPT vs CD4⁺_PERI 6 days after their transfer into CD45.2⁺B6. (G) Graphic summary of the mean proliferation ± standard error of CD4⁺_PERI and CD4⁺_SPT after 6 days of IL-7 treatment. (H) Graphic summary of CD4/CD8 ratio of T_PERI and T_SPT after 6 days of IL-7 treatment. (I) Graphic representation of the mean number ± standard error of CD4⁺_PERI and CD4⁺_SPT recovered in the LN of PBS- and IL-7–treated mice. Data show between 6 and 8 mice pooled from 2 to 3 independent experiments.