Human T cell generation is restored in CD3δ severe combined immunodeficiency through adenine base editing

• Published in: Cell Vol. 186; no. 7; pp. 1398 - 1416.e23
• Main Authors: McAuley, Grace E., Yiu, Gloria, Chang, Patrick C, Newby, Gregory A., Campo-Fernandez, Beatriz, Fitz-Gibbon, Sorel T., Wu, Xiaomeng, Kang, Sung-Hae L., Garibay, Amber, Butler, Jeffrey, Christian, Valentina, Wong, Ryan L., Everette, Kelcee A., Azzun, Anthony, Gelfer, Hila, Seet, Christopher S., Narendran, Aru, Murguia-Favela, Luis, Romero, Zulema, Wright, Nicola, Liu, David R., Crooks, Gay M., Kohn, Donald B.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 30-03-2023
• Subjects: Animals; artificial thymic organoid; base editing; CD3 Complex; CD3D severe combined immune deficiency; CITE-seq; Gene Editing; hematopoietic stem and progenitor cells; Humans; Mice; Mice, SCID; Receptors, Antigen, T-Cell - genetics; Severe Combined Immunodeficiency - genetics; Severe Combined Immunodeficiency - therapy; T-Lymphocytes; hematopoietic stem and progenitor cells; artificial thymic organoid; base editing; CD3D severe combined immune deficiency; CITE-seq
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/j.cell.2023.02.027

CD3δ SCID is a devastating inborn error of immunity caused by mutations in CD3D, encoding the invariant CD3δ chain of the CD3/TCR complex necessary for normal thymopoiesis. We demonstrate an adenine base editing (ABE) strategy to restore CD3δ in autologous hematopoietic stem and progenitor cells (HSPCs). Delivery of mRNA encoding a laboratory-evolved ABE and guide RNA into a CD3δ SCID patient’s HSPCs resulted in a 71.2% ± 7.85% (n = 3) correction of the pathogenic mutation. Edited HSPCs differentiated in artificial thymic organoids produced mature T cells exhibiting diverse TCR repertoires and TCR-dependent functions. Edited human HSPCs transplanted into immunodeficient mice showed 88% reversion of the CD3D defect in human CD34+ cells isolated from mouse bone marrow after 16 weeks, indicating correction of long-term repopulating HSCs. These findings demonstrate the preclinical efficacy of ABE in HSPCs for the treatment of CD3δ SCID, providing a foundation for the development of a one-time treatment for CD3δ SCID patients.
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•BE targets CD3δ SCID-causing mutations•BE of CD3δ SCID stem cells restores T lymphopoiesis and TCR diversity•Development of CD3δ SCID stem cells is blocked at the double positive precursor stage•BE is superior to homology-directed repair in correction of CD3δ SCID
The genetic mutation underlying a severe immune system deficiency can be corrected by adenine base editing of human patient stem cells, restoring the ability of these cells to develop into functional T cells in model systems, and paving the path for future treatment of CD3δ SCID in patients.