Fig. 3

IL-1β secretion induced by food-grade SAS particles depends on uptake by macropinocytosis. Immature DCs were incubated (18 h, 37 °C) with particles to test for IL-1β secretion. Asterisks denote significant differences between SAS treatments and controls (*p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001). a DCs were exposed to particles (250 μg ml⁻¹) and supernatants analyzed for IL-1β. Control reactions contained medium (CTR), 6 μg ml⁻¹ ODN1668 (mimicking microbial DNA) or 1 μg ml⁻¹ lipopolysaccharide (LPS). One-way ANOVA with Dunnet’s correction; n = 3–9; error bars, s.e.m. b Dose dependence of IL-1β secretion stimulated by SAS particles. Unpaired two-tailed t-test (n = 3–12). c Time dependence of IL-1β secretion stimulated by SAS particles (250 μg ml⁻¹). Unpaired two-tailed t-test (n = 4). d Flt3L-generated immature DCs were incubated for 18 h at 37 °C with 13-nm SAS (250 μg ml⁻¹) alone or in the presence of cytochalasin D (1.5 μg ml⁻¹), rottlerin (1.5 μg ml⁻¹) or Z-VAD (10 μg ml⁻¹). Results represent fold changes relative to vehicle controls (one-way ANOVA with Dunnet’s correction, n = 3–12). e Release of IL-1α into the cell culture supernatant stimulated by LPS (1 μg ml⁻¹) but not by 13-nm SAS particles. Asterisks denote significant differences between the LPS treatment and controls containing only culture medium. Cytokine levels below detection limit (4 pg ml⁻¹) are indicated as not detectable (nd). One-way ANOVA with Dunnet’s correction; n = 4; error bars, s.e.m. f Release of TNF-α into the cell culture supernatant stimulated by LPS (1 μg ml⁻¹) but not by 13-nm SAS particles (nd, cytokine levels below the detection limit of 8 pg ml⁻¹. Asterisks denote significant differences between the LPS treatment and controls containing only culture medium. One-way ANOVA with Dunnet’s correction; n = 4; error bars, s.e.m.