Dual CD8 and TCR editing in regulatory T cells mediates HLA-A2-restricted tissue-specific homing

Raphaël Porret; Fanny Lebreton; Eleonora Pace; Evangelos Stefanidis; Aikaterini Semilietof; Philippe Guillaume; Spiros Georgakis; Oscar Alfageme-Abello; Ana Alcaraz-Serna; Laura Ermellino; Rebecca Cecchin; Erica Lana; Morteza Hafezi; Francesco Procopio; Kevin Bellofatto; Greta Maria Paola Giordano Attianese; Vincent Zoete; Matthieu Perreau; Constantinos Petrovas; Melita Irving; Ekaterine Berishvili; Qizhi Tang; Yannick D Muller

doi:10.1016/j.ymthe.2026.02.028

Dual CD8 and TCR editing in regulatory T cells mediates HLA-A2-restricted tissue-specific homing

Mol Ther. 2026 Jun 3;34(6):3388-3404. doi: 10.1016/j.ymthe.2026.02.028. Epub 2026 Feb 18.

Authors

Raphaël Porret¹, Fanny Lebreton², Eleonora Pace³, Evangelos Stefanidis⁴, Aikaterini Semilietof⁴, Philippe Guillaume⁴, Spiros Georgakis⁵, Oscar Alfageme-Abello³, Ana Alcaraz-Serna³, Laura Ermellino³, Rebecca Cecchin³, Erica Lana³, Morteza Hafezi⁴, Francesco Procopio³, Kevin Bellofatto², Greta Maria Paola Giordano Attianese⁴, Vincent Zoete⁴, Matthieu Perreau¹, Constantinos Petrovas⁵, Melita Irving⁴, Ekaterine Berishvili², Qizhi Tang⁶, Yannick D Muller⁷

Affiliations

¹ Division of Immunology and Allergy, Lausanne University Hospital and University of Lausanne, 1005 Lausanne, Switzerland; Centre for Human Immunology Lausanne, 1005 Lausanne, Switzerland.
² Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals, 1205 Geneva, Switzerland; Laboratory of Tissue Engineering and Organ Regeneration, Department of Surgery, University of Geneva, 1204 Geneva, Switzerland.
³ Division of Immunology and Allergy, Lausanne University Hospital and University of Lausanne, 1005 Lausanne, Switzerland.
⁴ Ludwig Institute for Cancer Research, Lausanne Branch, University of Lausanne, 1066 Lausanne, Switzerland.
⁵ Department of Laboratory Medicine and Pathology, Institute of Pathology, Lausanne University Hospital and University of Lausanne, 1005 Lausanne, Switzerland.
⁶ Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA.
⁷ Division of Immunology and Allergy, Lausanne University Hospital and University of Lausanne, 1005 Lausanne, Switzerland; Centre for Human Immunology Lausanne, 1005 Lausanne, Switzerland. Electronic address: yannick.muller@chuv.ch.

PMID: 41709576
PMCID: PMC13239781 (available on 2027-06-03)
DOI: 10.1016/j.ymthe.2026.02.028

Abstract

Type 1 diabetes (T1D) is marked by the overexpression of class I major histocompatibility complex (MHC) antigens in pancreatic islets, which are targeted by islet-specific CD8⁺ T cells. Here, we aimed to improve regulatory T cell (Treg) infiltration into pancreatic islets by redirecting their specificity toward class I-restricted islet antigens. We functionally validated two islet-specific HLA-A2 (∗02:01)-restricted T cell receptors (TCRs), one specific for ZnT8_186-194 (clone D222D) and the second for IGRP_265-273 (clone 32), by dual-locus (TRAC/CD4) homology-directed editing. Clone D222D was peptide specific and CD8αβ dependent, while clone 32 exhibited antigen promiscuity and showed CD8α dependency. Engineered CD4^to8 TCR Tregs maintained stable phenotypes, in vitro suppressive function compared to their polyclonal counterparts, and showed co-receptor-dependent migration in vivo. This approach demonstrates that TCR specificity, reflected by its functional activity, is crucial for tissue-specific trafficking, paving the way to improve the efficacy of Treg therapies for T1D.

Keywords: CD8 editing; HLA-A2; Treg therapy; engineered TCR; islet; migration; regulatory T cell; tolerance; type 1 diabetes.