Fig. 6. T cells must display metabolic plasticity to adapt to changes in nutrient and oxygen availability in vivo.
TEFF (green) cells must adapt to varying oxygen and nutrient levels depending on environmental context. Lymphoid organs (middle) are considered to be nutrient- and oxygen-replete areas, whereas sites of inflammation (left) and the tumor micro-environment (right) contain hypoxic areas with fluctuations in nutrient availability. At sites of inflammation, nutrient and oxygen availability may become limited because of the metabolic activity of cells at the site of inflammation, necrosis of infected cells, and oxygen consumption by neutrophils. Tumor microenvironments can be highly hypoxic resulting from insufficient vascularization. Additionally, T cells must compete with tumor cells for nutrients such as glucose.