aPC reduces α-KG and glutamine in T cells. (A) Bar graph with dot plot of TCA cycle metabolites (liquid chromatography mass spectrometry [LC-MS] analysis, n = 5) in human CD4⁺CD25⁻ cells 24 hours after stimulation with αCD3 and αCD28 without (T) or with aPC (T + aPC) preincubation. (B-C) Bar graph with dot plot summarizing gene expression (messenger RNA [mRNA], quantitative PCR [qPCR]) of the glucose transporter GLUT1 (B, n = 4) and representative flow cytometry histogram (top) and bar graph with dot plot summarizing glucose (fluorescently labeled glucose, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose [2-NBDG], below) uptake into human CD4⁺CD25⁻ cells 24 hours after stimulation with αCD3 and αCD28 without (T) or with aPC (T + aPC) preincubation (n = 4). (D) Cartoon depicting the fueling of α-KG via glutaminolysis. (E-F) Bar graph with dot plot summarizing intracellular levels of glutamine and glutamate (E, LC-MS analysis, n = 4) and gene expression (mRNA, qPCR) of amino acid transporters (F, n = 3) in human cells as described for panel A. The data are shown as the mean ± SEM, and statistical significance was determined by a 2-tailed Student t test for the panels A-C,E-F: ∗P < .05, ∗∗P < .01, and ∗∗∗P < .005; ns, nonsignificant. Cartoon for panel D was created using BioRender.com.