Translational repression of 5' TOP mRNAs in chronically activated CD8+ T cells in vitro

T cell exhaustion is a dysfunctional state that arises during chronic infections and cancer, characterized by impaired effector functions and sustained expression of inhibitory receptors. While transcriptional, epigenetic, and metabolic rewiring have been well documented in exhausted T cells, a comprehensive understanding of how translation is regulated in this state remains incomplete. To address this gap, we performed ribosome profiling and RNA sequencing on in vitro chronically activated human CD8+ T cells to globally assess translational control during a model of T cell exhaustion. Our analyses reveal a marked repression of 5' terminal oligopyrimidine (TOP) mRNAs during chronic activation. Unexpectedly, we demonstrate that this translational repression occurs despite evidence of elevated mTOR activity. These findings uncover a previously unknown layer of translational control in exhausted T cells.