Recent thymic emigrants CD4⁺ do not proliferate more than peripheral CD4⁺ T cells during IL-7 therapy. (A) Schematic of the experimental design where CD45.2⁺CD4⁺_PERIGFP⁺, CD45.2⁺CD4⁺_PERIGFP⁻, and thymic CD45.2⁺CD8⁻CD4⁺_SPTGFP⁺ cells were sorted from LNs or thymuses of CD45.2⁺Rag^−/−GFP mice and stained with CFSE prior to their transfer into CD45.1⁺C57BL/6 mice. Recipient mice were then treated with PBS (vehicle) or rhIL-7 (10 μg/day) for 6 days. (B) Representative flow cytometric analysis of CFSE (CTV)–labeled CD4⁺_PERIGFP⁺ and CD4⁺_PERIGFP⁻ and CD4⁺_SPTGFP⁺ found in the LN of PBS- and IL-7–treated animals 7 days post transfer. (C) Graphic summary of the percentage of proliferating cells ± standard error of CD4⁺_PERIGFP⁺, CD4⁺_PERIGFP⁻, and CD4⁺_SPTGFP⁺ based on the dilution of CFSE staining after 6 days of IL-7 therapy. (D) Phenotypic analysis of CD4⁺_PERIGFP⁺, CD4⁺_PERIGFP⁻, and CD4⁺_SPTGFP⁺. Data show 2 animals per group from 2 experiments.