Figure 2.

Exposure to serum obtained after a high-fat shake, but not after a common breakfast shake, induces trained immunity in healthy human monocytes

(A) Graphical outline of the design of the in vitro experiments. Adherent healthy human monocytes were exposed to serum obtained before (t = 0 h; CS0/HFS0) and at several time points after (t = 2 h [CS2/HFS2], t = 4 h [CS4/HFS4], and t = 6 h [CS6/HFS6]) consumption of either the reference or high-fat shake. After 24 h incubation time, cells were rested and differentiated into macrophages. On day 6, the cells were restimulated with Toll-like receptor (TLR)-agonists (TLR4; lipopolysaccharide [LPS] and TLR2; Pam3Cys [P3C]) for another 24 h before cytokine production was measured with ELISA. Created with BioRender.com.

(B) Serum obtained after the high-fat shake increased TNF-α and IL-6 production of human monocyte-derived macrophages upon secondary stimulation with LPS, with the highest cytokine production after stimulation with serum obtained at t = 6 h (n = 17).

(C) Cytokine production capacity was measured after 24 h exposure to reference shake serum (CS) and the high-fat shake serum (HFS). Data are presented as fold of change to the fasting serum obtained before consumption of the control shake (CS0) or the high-fat shake (HFS0) (n = 11). Median ± IQR. ∗ indicates two-sided p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001, Wilcoxon signed-rank test. CS, serum after the reference shake; HFS, serum after the high-fat shake.

See also Figure S2.