Figure 1.

Effect of 1,25(OH)₂D₃ on the human periodontal ligament stem cells hPDLSCs mediated suppression of cluster of differentiation (CD)4⁺ T lymphocyte proliferation in the presence of tumor necrosis factor (TNF)-α or interleukin (IL)-1β or interferon (IFN)-γ. Primary hPDLSCs were cocultured with allogenic CD4⁺ T lymphocytes activated by 10 µg/mL phytohemagglutinin (PHA) in the presence of 10 ng/mL TNF-α (a) or 5 ng/mL IL-1β (b) or 100 ng/mL IFN-γ (c) and in the absence or presence of 100 nM 1,25(OH)₂D₃. Activated CD4⁺ T lymphocytes treated with different stimuli in the absence of hPDLCs served as the control. After five days, CD4⁺ T lymphocyte proliferation was assessed by carboxyfluorescein succinimidyl ester (CFSE) proliferation assay calculating the percentage of at least once divided CD4⁺ T lymphocytes. (d) shows the extent of the 1,25(OH)₂D₃ effect on CD4⁺ T lymphocyte proliferation regarding differently-treated hPDLSCs (expressed in % of corresponding cytokine treatment). All data are presented as mean ± S.E.M from five independent experiments using hPDLSCs from five different patients. * Significantly different (p < 0.05) compared between groups as indicated. § Significantly lower (p < 0.05) compared to appropriate groups without hPDLSCs.