Figure 8

Carnosol and curcumin treated DC have a reduced capacity to stimulate allogeneic CD4⁺ T cells. DC from healthy donors (n = 6–7) were treated with carnosol or curcumin (2.5–10 µM) for 6 hours prior to stimulation with LPS. After 24 hours, DC were washed and cultured at a 1:10 ratio with allogeneic purified CD4⁺ T cells. Immature DC (iDC) were also cultured with CD4⁺ T cells as an allogeneic control. After 5 days CD4⁺ T cells were analysed for proliferation by flow cytometry and supernatants were measured for IFNγ concentration by ELISA. (A) Histograms depicting proliferation of CD4⁺ T cells co-cultured with either control, carnosol or curcumin treated allogeneic DC, as measured by CTV fluorescence. Data shown is from one healthy donor. (B) Pooled data depicting mean (±SEM) percentage proliferation of CD4⁺ T cells cultured with control DC or DC treated with different concentrations of carnosol or curcumin. Statistical significance was determined by one-way ANOVA, with Tukey’s multiple comparisons post hoc test to compare means of all groups. Pooled data depicting mean (±SEM) percentage reduction in IFNγ in T cells cultured with (C) curcumin or (D) carnosol treated DC matured with LPS. Statistical significance was determined by one-way ANOVA, with Dunnett’s multiple comparisons post hoc test to compare means of all treatment groups to the control group. (****p < 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05).