Creatine transport and creatine kinase activity is required for CD8+ Tcell immunity.

Abstract

The factors that promote Tcell expansion are not fully known. Creatine is an abundant circulating metabolite that has recently been implicated in Tcell function; however, its cell-autonomous role in immune-cell function is unknown. Here, we show that creatine supports cell-intrinsic CD8+ Tcell homeostasis. We further identify creatine kinase B (CKB) as the creatine kinase isoenzyme that supports these Tcell properties. Loss of the creatine transporter (Slc6a8) or Ckb results in compromised CD8+ Tcell expansion in response to infection without influencing adenylate energy charge. Rather, loss of Slc6a8 or Ckb disrupts naive Tcell homeostasis and weakens TCR-mediated activation of mechanistic target of rapamycin complex 1 (mTORC1) signaling required for CD8+ Tcell expansion. These data demonstrate a cell-intrinsic role for creatine transport and creatine transphosphorylation, independent of their effects on global cellular energy charge, in supporting CD8+ Tcell homeostasis and effector function.