Upregulation of TNFR2 Precedes TOX Expression by Exhausted T cells and Restricts Antitumor and Antiviral Immunity.

PURPOSE: Exhaustion represents a collection of programmed T-cell differentiation states and an important mode of T-cell dysfunction. T-cell progression from progenitor to terminal exhaustion is associated with upregulation of the transcription factor thymocyte selection-associated HMG box (TOX). Our understanding of factors regulating TOX expression and the transition from progenitor to terminal exhaustion, however, remains incomplete. EXPERIMENTAL DESIGN: Single-cell RNA sequencing was used to evaluate the expression of TNF receptors on human and murine tumor-infiltrating CD8+ T cells. Flow cytometry was utilized to assess exhaustion markers and TNF receptors on CD8+ T cells. Bulk RNA sequencing was used to demonstrate the role of TNFR2 on the overall exhaustion profile. Finally, the effect of TNFR2 on the overall antitumor response was established using TNFR2-knockout (KO) mice and an antagonist. RESULTS: We reveal that upregulation of TNFR2 coincides with the gain of phenotypic markers and functions reflective of terminal exhaustion. Loss of TNFR2 affords a novel population of T cells that expresses TIM3 but possesses diminished TOX levels and contains functional characteristics of both progenitor and terminally exhausted cells. TIM3+ TNFR2-KO T cells exhibit reduced exhaustion transcriptional programs and enhanced AP1 pathway signatures. Finally, TNFR2-KO mice demonstrate improved T cell-dependent control of tumor and chronic lymphocytic choriomeningitis infection, whereas pharmacologic antagonism of TNFR2 licenses responses to checkpoint blockade in multiple subcutaneous and intracranial tumor models. CONCLUSIONS: Our data place TNFR2 signaling as a potential upstream regulator of TOX expression in T cells and propose TNFR2 antagonism as a novel immunotherapeutic strategy.