Fig. 6.

Inhibition of lipopolysaccharide/interferon (LPS/IFN)-γ-induced dendritic cell (DC) maturation and function by curcumin. (a) CD11c ⁺ DC surface expression of co-stimulatory molecules and major histocompatibility complex (MHC)-II with the corresponding percentage and mean fluorescence intensity (MFI) (brackets) are shown for 20 μM curcumin- (bold type, thick line) and vehicle-treated or LPS/IFN-γ-stimulated conditions (L/I, normal type, dashed line). Representative flow cytometric data from at least three independent experiments and MFI quantification from stimulated (L/I) versus curcumin-treated stimulated DC (L/I + Cur20) is shown; *P < 0·05 by unpaired one-tailed Student's t-test, n = 3. (b) Proinflammatory cytokines and nitric oxide (NO) secretion *P < 0·05; ***P < 0·001 versus LPS/IFN-γ-stimulated DC, n = 3 by analysis of variance (anova) followed by Bonferroni's multiple comparison test. (c) Dextran-fluorescein isothiocyanate (FITC) uptake by CD11c + DC expressed by percentage and MFI (brackets) is shown for 20 mM curcumin- (bold type, thick line) and vehicle-treated or LPS/IFN-γ-stimulated conditions (normal type, dashed line); shaded area represents DC autofluorescence. Representative fluorescence activated cell sorter (FACS) data of three independent experiments. (d) Mixed leucocyte reaction (MLR) shows a reduction in T lymphocyte proliferation when co-cultured with LPS-stimulated curcumin-treated DC versus LPS-stimulated, **P < 0·01; ***P < 0·001; n = 3, by anova followed by Bonferroni's multiple comparison test for each T cell : antigen-presenting cell (APC) ratio.