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

Abstract

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.