title: Correction of murine SCID-X1 by lentiviral gene therapy using a codon-optimized IL2RG gene and minimal pretransplant conditioning.
abstract: Clinical trials have demonstrated the potential of ex vivo hematopoietic stem cell gene therapy to treat X-linked severe combined immunodeficiency (SCID-X1) using γ-retroviral vectors, leading to immune system functionality in the majority of treated patients without pretransplant conditioning. The success was tempered by insertional oncogenesis in a proportion of the patients. To reduce the genotoxicity risk, a self-inactivating (SIN) lentiviral vector (LV) with improved expression of a codon optimized human interleukin-2 receptor γ gene (IL2RG) cDNA (coγc), regulated by its 1.1 kb promoter region (γcPr), was compared in efficacy to the viral spleen focus forming virus (SF) and the cellular phosphoglycerate kinase (PGK) promoters. Pretransplant conditioning of Il2rg(-/-) mice resulted in long-term reconstitution of T and B lymphocytes, normalized natural antibody titers, humoral immune responses, ConA/IL-2 stimulated spleen cell proliferation, and polyclonal T-cell receptor gene rearrangements with a clear integration preference of the SF vector for proto-oncogenes, contrary to the PGK and γcPr vectors. We conclude that SIN lentiviral gene therapy using coγc driven by the γcPr or PGK promoter corrects the SCID phenotype, potentially with an improved safety profile, and that low-dose conditioning proved essential for immune competence, allowing for a reduced threshold of cell numbers required.
authors.affiliation: Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Marshall W
authors.initials: MW
authors.lastname: Huston
authors.forename: Niek P
authors.initials: NP
authors.lastname: van Til
authors.forename: Trudi P
authors.initials: TP
authors.lastname: Visser
authors.forename: Shazia
authors.initials: S
authors.lastname: Arshad
authors.forename: Martijn H
authors.initials: MH
authors.lastname: Brugman
authors.forename: Claudia
authors.initials: C
authors.lastname: Cattoglio
authors.forename: Ali
authors.initials: A
authors.lastname: Nowrouzi
authors.forename: Yuedan
authors.initials: Y
authors.lastname: Li
authors.forename: Axel
authors.initials: A
authors.lastname: Schambach
authors.forename: Manfred
authors.initials: M
authors.lastname: Schmidt
authors.forename: Christopher
authors.initials: C
authors.lastname: Baum
authors.forename: Christof
authors.initials: C
authors.lastname: von Kalle
authors.forename: Fulvio
authors.initials: F
authors.lastname: Mavilio
authors.forename: Fang
authors.initials: F
authors.lastname: Zhang
authors.forename: Mike P
authors.initials: MP
authors.lastname: Blundell
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Thrasher
authors.forename: Monique M A
authors.initials: MM
authors.lastname: Verstegen
authors.forename: Gerard
authors.initials: G
authors.lastname: Wagemaker
mesh_terms: D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology; D003062:Codon; D015316:Genetic Therapy; D018380:Hematopoietic Stem Cell Transplantation; D053631:Interleukin Receptor Common gamma Subunit / Q000235:genetics*; D016086:Lentivirus / Q000235:genetics*; D051379:Mice; D016513:Mice, SCID; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D016511:Severe Combined Immunodeficiency / Q000276:immunology / Q000628:therapy*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D003062:Codon; C507942:Il2rg protein, mouse; D053631:Interleukin Receptor Common gamma Subunit; D011948:Receptors, Antigen, T-Cell