Fig. 1. T cell metabolism changes over the course of an immune response.

T cells display distinct metabolic profiles depending on their state of activation. Naïve T cells (T_N, blue) are metabolically quiescent; they adopt a basal level of nutrient uptake and use OXPHOS as their primary pathway of ATP production. Upon immune challenge, T_EFF (green) cells shift to a state of metabolic activation characterized by increased nutrient uptake, elevated glycolytic and glutaminolytic metabolism, biomass accumulation, and reduced mitochondrial SRC. T_EFF cells preferentially use glycolysis over OXPHOS for ATP production. Transition to the T_M (orange) stage is characterized by a quiescent metabolism, with increased reliance on FAO to fuel OXPHOS. Mitochondrial mass and SRC are elevated in T_M cells, suggesting that these cells are metabolically primed to respond upon reinfection.