Germinal center B cells selectively oxidize fatty acids for energy while conducting minimal glycolysis

Germinal center B cells (GCBCs) are critical for generating long-lived humoral immunity. How GCBCs meet the energetic challenge of rapid proliferation is poorly understood. Dividing lymphocytes typically rely on aerobic glycolysis over oxidative phosphorylation for energy. Here we report that GCBCs are exceptional among proliferating B and T cells as they actively oxidize fatty acids (FAs) and conduct minimal glycolysis. In vitro, GCBCs had a very low glycolytic extracellular acidification (ECAR) but consumed oxygen in response to FAs. [(13)C(6)]-glucose feeding revealed that GCBCs generate significantly less phosphorylated glucose and little lactate. Further, GCBCs did not metabolize glucose into TCA cycle intermediates. Conversely, [(13)C(16)]-palmitic acid labeling demonstrated that GCBCs generate most of their acetyl-CoA and acetylcarnitine from FAs. FA oxidation (FAO) was functionally important, as drug-mediated and genetic dampening of FAO resulted in a selective reduction GCBCs. Hence, GCBCs appear to uncouple rapid proliferation from aerobic glycolysis.