Figure 1. Low-dose IL-2 treatment expands CD4⁺CD25⁺Foxp3⁺ regulatory T cells and increases their immunosuppressive function.

Corneal transplantation onto inflamed graft beds was performed and low doses of IL-2 (1μg/25g mouse body weight) or saline (control) were administered. Draining lymph nodes were analyzed at day 7 post-transplantation using flow cytometry. (A) Representative dot plots of saline treated and IL-2 treated recipients showing frequencies of CD25⁺Foxp3⁺Tregs among CD4⁺ cells. (B, C) Bar graphs showing mean ± standard deviation (SD) of the frequencies of CD4⁺CD25⁺Foxp3⁺ Tregs and CD25 MFI in CD4⁺CD25⁺ Tregs, respectively (frequencies are measured among total CD4⁺ lymph node cells). (D) Representative dot plots of saline treated and IL-2 treated recipients showing frequencies of CTLA-4^hi Tregs among CD4⁺CD25⁺Foxp3⁺T cells. (E, F) Bar graphs showing mean ± SD of CTLA-4⁺ Tregs and CTLA-4 MFI among CD25⁺CTLA-4^hi Tregs, respectively (frequencies are measured among total CD4⁺CD25⁺ lymph node cells). (G) Relative changes in mRNA levels of IL-10 and Foxp3 in DLNs. (H) Treg suppression assay showing proliferation of naïve CD4⁺CD25⁻T cells in the presence of CD4⁺CD25⁺Tregs isolated from IL-2 treated vs. saline injected mice or naïve controls (N=5 mice/group).