Figure 4.

DCs treated with NP[OVA+Dex] induce Foxp3⁺ Treg cells from naïve CD4⁺CD25⁻ T cells.

Notes: (A) Induction of Foxp3⁺ Treg cells from OVA-specific CD4⁺CD25⁻ T cells. DCs generated from C57BL/6 mouse bone marrow cells were stimulated with IFN-γ (50 ng/mL) plus TNF-α (50 ng/mL), or treated with NP[OVA] or NP[OVA+Dex] (10 μg/mL as OVA) for 48 h. DCs were co-cultured with CD4⁺CD25⁻ T cells isolated from the spleens of OT-II mice at a ratio of 1:10 in a medium containing recombinant human IL-2 (100 U/mL) for 4 days. Cells were gated on CD4⁺TCR Vα2⁺ cells and the expression of CD25 and Foxp3 was analyzed. The data show representative histograms of three independent experiments. (B) The proportion of CD25⁺Foxp3⁺ Treg cells in the CD4⁺TCR Vα2⁺ cell population of each experimental group is shown. (C) Induction of Foxp3⁺ Treg cells in allogeneic MLR. DCs were then co-cultured with CD4⁺CD25⁻ T cells isolated from the spleens of BALB/c mice at a ratio of 1:10 in a medium containing recombinant human IL-2 (100 U/mL) for 4 days. Cells were gated on CD4⁺ cells and the expression of CD25 and Foxp3 was analyzed. The data show representative histograms of three independent experiments. (D) The proportion of CD25⁺FoxP3⁺ Treg cells in the CD4⁺ cell population of each experimental group is shown. The data are presented as mean ± SD of three independent experiments. The data are presented as the mean ± SD of three independent experiments. **P<0.01, ***P<0.001. “ns” indicates no significant difference.

Abbreviations: DCs, dendritic cells; Dex, dexamethasone; Foxp3, forkhead box P3; IFN-γ, interferon-γ; IL-2, interleukin-2; NP[OVA+Dex], nanoparticles containing ovalbumin and dexamethasone; MLR, Mixed lymphocyte reaction; NP[OVA], nanoparticles containing only ovalbumin; OVA, ovalbumin; SD, standard deviation; TCR, T cell receptor; TNF-α, tumor necrosis factor-α; Treg cells, regulatory T cells.