Figure 5.

MDSCs effectively suppress the proliferation of CD4⁺ T cells and antigen-specific CD4⁺ T cells responses. (A) CD4⁺ T cells isolated from healthy adult PBMCs were used as stimulators from three different donors. Adult monocyte derived mature DCs (1 × 10⁴ cells) were mixed with the autologous CD4⁺ T cells (1 × 10⁵ cells) in the presence or absence 1 × 10⁴ MDSCs. The cells were cultured for 5 days and 1 μCi [³H]thymidine was added to the wells for 18 hr before harvesting. The incorporation of [³H]thymidine was determined using a liquid β-scintillation counter. (B) The HCMV pp65 RNA-electroporated mature DCs were added to a 96-well microplate at a concentration of 1 x 10⁴ cells/well in 10% complete RPMI 1640. 1 × 10⁵ autologous CD4⁺ T cells were then added to the well as a stimulator in the presence or absence MDSCs (1 × 10⁴). An ELISPOT assay for human IFN-γ was conducted according to the manufacturer's protocol. Data are mean ± S.E.M. of three independent experiments, each performed in triplicate. ****p < 0.0001.