Regulatory T Cell—Derived Amphiregulin Consolidates Transplant Tolerance via EGFR-Mediated T Cell Exhaustion 2263100

Abstract Introduction Durable transplant tolerance remains a major challenge. Prior studies have linked amphiregulin (Areg) to Treg cell stability, anti-inflammatory function, and regulation of T-cell differentiation and tumor immune evasion. As a mitogenic and cell differentiation ligand of EGFR, Areg may enable Tregs to restrain allospecific immune responses by activating exhaustion-associated transcriptional programs such as TOX and Nur77. We hypothesized that Tregs enforce long-term tolerance by inducing controlled Teff cell exhaustion through Areg—EGFR signaling. Methods Using a nonhuman primate model of allogeneic islet transplantation, we integrated high-dimensional CyTOF, donor MHC-II tetramer tracking, and ex vivo coculture assays to define Areg+Treg—EGFR+Teff cell interactions. Functional perturbations included Areg silencing in Tregs and EGFR neutralization/silencing in responder T cells to dissect causal signaling. Results Tolerant recipients displayed enrichment of Areg+ST2+FoxP3+ Treg cells, and HelioshiEOMEShiCCR2+ and EGFR+TOX+Nur77+ exhausted CD8+ T cells within splenic allospecific clusters. Trajectory and pseudotime analyses showed that activated naïve/memory CD8+ Teff cells progressively acquired exhaustion features under Areg+Treg influence. EGFR blockade or Areg knockdown abrogated Treg-mediated suppression, restored cytokine and perforin expression, and diminished TOX+Nur77+TIGIT+ exhaustion. Conclusion These findings establish the Areg+Treg—EGFR+Teff axis as a critical immunoregulatory mechanism that consolidates transplant tolerance by linking Treg-derived Areg signaling to Teff exhaustion. Mechanistically, Areg—EGFR engagement drives TOX—Nur77 transcriptional and metabolic reprogramming, restraining effector activation and sustaining immune quiescence. Funding Source NIH R21 Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)