(A) Fructose 6-phosphate and glutamine may be metabolized by glycolysis and glutaminolysis, respectively, or enter the hexosamine pathway to supply UDP-GlcNAc to the Golgi branching enzymes Mgat1, 2, 4 and 5. HK: hexokinase, GPI: glucose-6-phosphate isomerase, PFK1: phosphofructokinase1, LDH: Lactate dehydrogenase, GFPT: glutamine-fructose-6-phosphate transaminase. (B–H) Flow cytometry (B,E–H), Western blot (C) and LC-MS/MS (D) analysis of purified mouse splenic CD4+ T-cells activated with anti-CD3+anti-CD28 for 4 days (B,E–H) or 3 days (C,D) with TH17 inducing conditions (TGFβ+IL-6+IL-23) or as indicated. PFK1-L (liver), PFK1-P (platelet), PFK1-M (muscle). (G) Co-incubation with doxycycline in vitro. (H) Doxycycline treatment in vivo, with Mgat1f/ftetO-Cre+ROSArtTA cells in right panel gated on L-PHA− population. (B,E–H) gated on CD4+. (B,D–H) Unpaired two tailed t-test with Welch’s (E) and Bonferroni corrections (B,E). **p<0.01; ***p<0.001. Data are mean ± s.e.m of triplicate cultures and representative of n ≥ 3 experiments. MFI, mean fluorescence intensity.