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Updated: Apr 18, 2026
Preparation and Gene Modification of Nonhuman Primate Hematopoietic Stem and Progenitor Cells
Published on: February 15, 2019
Gene therapy studies in a canine model of X-linked severe combined immunodeficiency
Peter J Felsburg1, Suk See De Ravin, Harry L Malech
11 Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania , Philadelphia, PA 19104.
Abstract:
Since the occurrence of T cell leukemias in the original human γ-retroviral gene therapy trials for X-linked severe combined immunodeficiency (XSCID), considerable effort has been devoted to developing safer vectors. This review summarizes gene therapy studies performed in a canine model of XSCID to evaluate the efficacy of γ-retroviral, lentiviral, and foamy viral vectors for treating XSCID and a novel method of vector delivery. These studies demonstrate that durable T cell reconstitution and thymopoiesis with no evidence of any serious adverse events and, in contrast to the human XSCID patients, sustained marking in myeloid cells and B cells with reconstitution of normal humoral immune function can be achieved for up to 5 years without any pretreatment conditioning. The presence of sustained levels of gene-marked T cells, B cells, and more importantly myeloid cells for almost 5 years is highly suggestive of transduction of either multipotent hematopoietic stem cells or very primitive committed progenitors.
Insights
Gene therapy for X-linked severe combined immunodeficiency (XSCID) using canine models shows durable T cell reconstitution without adverse events. Safer viral vectors achieved sustained immune function in multiple cell types, suggesting stem cell transduction.
Area of Science:
- Immunology
- Gene Therapy
- Hematology
Background:
- X-linked severe combined immunodeficiency (XSCID) poses significant health risks.
- Previous gene therapy trials using gamma-retroviral vectors led to T cell leukemias.
- Development of safer gene therapy vectors is crucial for XSCID treatment.
Purpose of the Study:
- To review gene therapy studies in a canine XSCID model.
- To evaluate gamma-retroviral, lentiviral, and foamy viral vectors for XSCID treatment.
- To assess a novel vector delivery method's efficacy and safety.
Main Methods:
- Utilized a canine model of XSCID.
- Administered gamma-retroviral, lentiviral, and foamy viral vectors.
- Monitored T cell reconstitution, thymopoiesis, and adverse events for up to 5 years.
- Assessed gene marking in myeloid, B, and T cells, and humoral immune function.
Main Results:
- Achieved durable T cell reconstitution and thymopoiesis without serious adverse events.
- Demonstrated sustained gene marking in myeloid and B cells, unlike human trials.
- Observed reconstitution of normal humoral immune function.
- Sustained multi-lineage gene marking suggests transduction of hematopoietic stem cells or early progenitors.
Conclusions:
- Canine XSCID models show promise for developing safer gene therapies.
- Lentiviral and foamy viral vectors offer potential advantages over gamma-retroviral vectors.
- Successful gene therapy can restore multi-lineage immune function without conditioning, indicating stem cell engraftment.
