Editorial overview: Immunometabolism

Energy metabolism is a key determinant of the immune response. Classical biochemistry has precisely dissected intracellular metabolic pathways, highlighting how cells adapt to different tasks requiring increasing energy demand. However, until about two decades ago, most immunologists assumed that immune cells were a realm apart that did not comply with the general rules of metabolic control effective in all other tissues. Little to no attention was paid to the possibility that different activation or differentiation states of immune cells, whether innate or adaptive, might be associated with different metabolic pathways or that different immunostimulatory factors might promote the preferential engagement of specific metabolic pathways. Likewise, no mentions were made about 'immunometabolism' in most immunology textbooks, and even 'Tlymphocyte exhaustion' is rarely mentioned. Rather, immune cells are not much different from other lineages for their metabolic requirements: they require ATP, metabolic substrates (glucose, fatty acids, but also lactate, glutamine, and other amino acids), and the oxidizing agent (oxygen) (although at times they can adapt to a limited supply) to make ATP from