The Battle over mTOR: An Emerging Theatre in Host–Pathogen Immunity

Mammalian target of rapamycin (mTOR) kinases are emerging as master regulators of cellular metabolism [1]. During an infection, pathogens seek nutrition to survive and often exploit host machinery that controls cellular metabolic processes. Moreover, pathogens can subvert host metabolism by targeting mTOR complexes to gain a replicative advantage. Conversely, host cells regulate the mTOR axis to facilitate pathogen clearance. Intriguingly, in addition to their role in the regulation of metabolism, mTOR complexes regulate both the quality and quantity of innate and adaptive immune responses. Here we propose that drugs strategically targeting mTOR, perhaps in opposing ways in distinct cell types, could influence the immunological outcome of host–pathogen interactions and also act as effective antibiotics by limiting pathogen replication.