MDSC-IL-13 negatively impact proliferation, activation, and effector function of donor T cells. Lethally irradiated BALB/c mice were transplanted with 15 × 10⁶ CFSE-labeled CD25-depleted B6 Ly5.1-expressing T cells alone or with 10 × 10⁶ CD11b purified MDSC-IL-13. (A) Day 4 splenocytes were analyzed via flow cytometry for CFSE dilution on CD4 and CD8 T cells. (B) Flow cytometry was used to detect the amount of CD3ζ present on CD4 and CD8 splenic T cells. (C) Graph of common activation markers (CD25 and CD62L) on CD4 and CD8 splenic T cells. (D) Intracellular cytokine staining was performed on LN CD4 and CD8 T cells to determine the percentage of cells producing IFN-γ.