CD8A and infection: During infection, pathogen-engaged DCs use three distinct signals (antigen, co-stimulation and cytokines) to stimulate catabolic CD8+ Tn cells to grow and differentiate into one of two CD8+ T-cell subsets; anabolic IL-7R−CD62L−KLRG1+ TE cells which rely on glycolysis, grow rapidly and exhibit effective killing activity, or catabolic and quiescent IL-7R+CD62L+KLRG1− TM cells which use mild FAO for economical energy supply (Figure 1B).