Assistant Professor University of Minnesota Hennepin County, Minnesota, United States
Disclosure(s):
Amar Singh, PhD: No financial relationships to disclose
Introduction/Rationale: 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.
