(A and B) Twelve-week-old, chow diet–fed, Acox1^Lampe1 mice and WT littermate controls were challenged i.p. with biotinylated capture Ab (20 μg/mouse) 3 hours prior to i.v. saline (NS) or LPS challenge (25 μg/mouse; ultrapure E. coli 0111:B4). Twenty-four hours later, serum was collected, and IL-6, TNF-α, IFN-γ, and IL-17A levels were quantified by IVCCA ELISA. (C) Supernatant IL-6 and IL-1β levels from BM-derived DCs (BMDC), of chow diet–fed, Acox1^Lampe1 mice and WT littermate controls stimulated for 24 hours with saline (NS) or LPS (100 ng/ml). (D) Splenic naive CD4⁺ T cells from chow diet–fed WT mice, isolated by negative selection using magnetic beads, were cultured under Th17 and Th1 polarizing conditions with or without peroxisomal β-oxidation inhibitor (thioridizine, 1 μM) and the frequency of IL-17A– and IFN-γexpressing cells were quantified by flow cytometry. (E and F) Splenic naive CD4⁺ T cells from 12-week-old, chow diet–fed, Acox1^Lampe1 mice and WT littermate controls, isolated by negative selection using magnetic beads, were cultured under Th17 and Th1 polarizing conditions, and the frequency of IL-17A– and IFN-γ–expressing cells was quantified by flow cytometry. (G) Frequency of total splenic Th1 (CD3⁺CD4⁺IFN-γ⁺IL-17A^–), Th17 (CD3⁺CD4⁺IL-17A⁺IFN-γ^–), and Treg (CD3⁺CD4⁺FOXP3⁺) in chow diet–fed Acox1^Lampe1 mice and WT littermate controls. Data represent means ± SEM. (A, B, and E–G) Unpaired Student’s t test; *P < 0.05, **P < 0.01. (C) One-way ANOVA followed by Tukey’s correction; *P < 0.05. White bars denote WT mice; black bars denote Acox1^Lampe1 mice. (A, B and D) Data combined from 2 independent experiments, n = 3–8/condition. (C and E) Data combined from 2 independent experiments, n = 7/condition. (F and G) A single experiment, n = 3–4/condition.