Figure 5. Downregulation of NKG2D expression in CD8⁺ T lymphocytes and NK cells after curcumin treatment. NKG2D expression on the cell surface of CD8+ T cells (A) and NK cells (B) was assayed before and after treatment with curcumin (1–4 μM) for 24 h by flow cytometry. Left-hand panels show a representative histogram after treatment with 4 μM curcumin for 24 h; on the right, box-plots indicate NKG2D expression in CD8⁺ T lymphocytes and NK cells from ten healthy donors before and after curcumin treatment (1–4 μM). Data are expressed as the Mean Fluorescence Intensity (MFI) of NKG2D expression. *p < 0.05.