Intrathymic adeno-associated virus gene transfer rapidly restores thymic function and long-term persistence of gene-corrected T cells

Marie Pouzolles (1) , Alice Machado (1) , Mickaël Guilbaud (2) , Magali Irla (3) , Sarah Gailhac (1) , Pierre Barennes (4) , Daniela Cesana (5) , Andrea Calabria (5) , Fabrizio Benedicenti (5) , Arnauld Sergé (6) , Indu Raman (7) , Quan-Zhen Li (7) , Eugenio Montini (5) , David Klatzmann (8, 4, 9) , Oumeya Adjali (2) , Naomi Taylor (1, 10) , Valérie Zimmermann (1)

1 IGMM - Institut de Génétique Moléculaire de Montpellier
2 Inserm UMR 1089 - Laboratoire de Thérapie Génique Translationnelle des Maladies Génétiques
3 CIML - Centre d'Immunologie de Marseille - Luminy
4 I3 - Immunologie - Immunopathologie - Immunothérapie [CHU Pitié Salpêtrière]
5 IRCCS San Raffaele Scientific Institute [Milan, Italie]
6 CRCM - Centre de Recherche en Cancérologie de Marseille
7 University of Texas Southwestern Medical Center [Dallas]
8 CIC-BTi - Centre d'investigation clinique Biothérapie [CHU Pitié-Salpêtrière]
9 CHU Pitié-Salpêtrière [AP-HP]
10 NCI-NIH - National Cancer Institute [Bethesda]

BACKGROUND: Patients with T-cell immunodeficiencies are generally treated with allogeneic hematopoietic stem cell transplantation, but alternatives are needed for patients without matched donors. An innovative intrathymic gene therapy approach that directly targets the thymus might improve outcomes. OBJECTIVE: We sought to determine the efficacy of intrathymic adeno-associated virus (AAV) serotypes to transduce thymocyte subsets and correct the T-cell immunodeficiency in a zeta-associated protein of 70 kDa (ZAP-70)-deficient murine model. METHODS: AAV serotypes were injected intrathymically into wild-type mice, and gene transfer efficiency was monitored. ZAP-70-/- mice were intrathymically injected with an AAV8 vector harboring the ZAP70 gene. Thymus structure, immunophenotyping, T-cell receptor clonotypes, T-cell function, immune responses to transgenes and autoantibodies, vector copy number, and integration were evaluated. RESULTS: AAV8, AAV9, and AAV10 serotypes all transduced thymocyte subsets after in situ gene transfer, with transduction of up to 5% of cells. Intrathymic injection of an AAV8-ZAP-70 vector into ZAP-70-/- mice resulted in a rapid thymocyte differentiation associated with the development of a thymic medulla. Strikingly, medullary thymic epithelial cells expressing the autoimmune regulator were detected within 10 days of gene transfer, correlating with the presence of functional effector and regulatory T-cell subsets with diverse T-cell receptor clonotypes in the periphery. Although thymocyte reconstitution was transient, gene-corrected peripheral T cells harboring approximately 1 AAV genome per cell persisted for more than 40 weeks, and AAV vector integration was detected. CONCLUSIONS: Intrathymic AAV-transduced progenitors promote a rapid restoration of the thymic architecture, with a single wave of thymopoiesis generating long-term peripheral T-cell function.

Mots clés: medulla formation; thymus; zeta-associated protein of 70kDa; Severe combined immunodeficiency; gene therapy; T-cell reconstitution; humoral immunity; intrathymic gene transfer; medulla formation

Domaines: Sciences du Vivant [q-bio]

Marie Pouzolles, Alice Machado, Mickaël Guilbaud, Magali Irla, Sarah Gailhac, et al.. Intrathymic adeno-associated virus gene transfer rapidly restores thymic function and long-term persistence of gene-corrected T cells. Journal of Allergy and Clinical Immunology, 2020, 145 (2), pp.679-697.e5. ⟨10.1016/j.jaci.2019.08.029⟩. ⟨hal-02350097⟩