T cell activation results in metabolic reprogramming. Naïve T cells have an oxidative metabolism, using glucose, glutamine, and fatty acids as fuel sources. The majority of ATP is generated via oxidative phosphorylation. Following activation by stimulation of the T cell receptor and co-receptors, the cells adopt a metabolic profile that resembles the metabolism of many cancer cells, consuming large quantities of both glucose and glutamine but performing relatively little oxidative phosphorylation. The majority of glucose-derived carbon is secreted as lactate, with the remainder being used for biosynthesis.