A self-inactivating lentiviral vector for SCID-X1 gene therapy that does not activate LMO2 expression in human T cells
- Sheng Zhou1,*,
- Disha Mody1,
- Suk See DeRavin2,
- Julia Hauer3,
- Taihe Lu1,
- Zhijun Ma1,
- Salima Hacein-Bey Abina3,
- John T. Gray1,
- Michael R. Greene1,
- Marina Cavazzana-Calvo3,
- Harry L. Malech2, and
- Brian P. Sorrentino1
- 1 Division of Experimental Hematology, Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN;
- 2 Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD;
- 3 INSERM U768, Universite Rene Descartes, and Hopital Necker-Enfants Malades, Paris, France
- * Corresponding author; email: sheng.zhou{at}stjude.org
Abstract
In order to develop safer and more effective vectors for gene therapy of X-linked severe combined immunodeficiency (SCID-X1), we have evaluated new self-inactivating (SIN) lentiviral vectors based on the HIV virus. The CL20i4-hγc-Revgen vector contains the entire human common gamma chain (γc) genomic sequence driven by the γc promoter. The CL20i4-EF1α-hγcOPT vector utilizes a promoter fragment from the eukaryotic elongation factor alpha (EF1α) gene to express a codon-optimized human γc cDNA. Both vectors contain a 400bp insulator fragment from the chicken β-globin locus within the SIN LTR. Transduction of bone marrow cells using either of these vectors restored T, B, and NK lymphocyte development and function in a mouse SCID-X1 transplant model. Transduction of human CD34+ bone marrow cells from SCID-X1 patients with either vector restored T cell development in an in vitro assay. In safety studies using a Jurkat LMO2 activation assay, only the CL20i4-EF1α-hγcOPT vector lacked the ability to transactivate LMO2 protein expression, while the CL20i4-hγc-Revgen vector significantly activated LMO2 protein expression. Also the CL20i4-EF1α-hγcOPT vector has not caused any tumors in transplanted mice. We conclude that the CL20i4-EF1α-hγcOPT vector is suitable for testing in a clinical trial based on these preclinical demonstrations of efficacy and safety.
- Submitted October 27, 2009.
- Accepted May 4, 2010.
- Copyright © 2005 American Society of Hematology
