Figure 1. The components for enhancing CD8+ Tm cell homeostasis and functions. Simplified representation of the three requirements of CD8+ Tm cells for development and homeostasis: (A) homeostatic cytokines such as IL-7, IL-15, and IL-21, (B) metabolites, and (C) metabolic pathways. (A) Cytokine stimulation maintains homeostatic proliferation by increasing the expression of survival-associated genes and inhibiting mitochondrial-mediated apoptosis. In addition, these cytokines enhance the surface expression of fatty acid transporters to enhance the uptake of FAs into cells and convert metabolism from glycolysis to FAO, a hallmark of Tm cells. (B) Metabolites: FAs produced by microbiota or other fuel for FAO in mitochondria for Tm cells. (C) The metabolism of Tm cells relies mainly on FAO, which is induced by (A) homeostatic cytokines and (B) metabolites.
