Abstract |
The main impediments to clinical application of haematopoietic stem cell (HSC) gene therapy for treatment of haemophilia A are the bone marrow transplant-related risks and the potential for insertional mutagenesis caused by retroviral vectors. To circumvent these limitations, we have adapted a non-myeloablative conditioning regimen and directed factor VIII (FVIII) protein synthesis to B lineage cells using an insulated lentiviral vector containing an immunoglobulin heavy chain enhancer-promoter. Transplantation of lentiviral vector-modified HSCs resulted in therapeutic levels of FVIII in the circulation of all transplanted mice for the duration of the study (six months). Immunostaining of spleen cells showed that the majority of FVIII was synthesised by B220+ B cells and CD138+ plasma cells. Subsequent challenge with recombinant FVIII elicited at most a minor anti-FVIII antibody response, demonstrating induction of immune hyporesponsiveness. All transplant recipients exhibited clot formation and survived tail clipping, indicating correction of their haemophilic phenotype. Therapeutic levels of FVIII could be transferred to secondary recipients by bone marrow transplantation, confirming gene transfer into long-term repopulating HSCs. Moreover, short-term therapeutic FVIII levels could also be achieved in secondary recipients by adoptive transfer of HSC-derived splenic B cells. Our findings support pursuit of B cell-directed protein delivery as a potential clinical approach to treat haemophilia A and other disorders correctable by systemically distributed proteins.
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Authors | Ali Ramezani, Lynnsey A Zweier-Renn, Robert G Hawley |
Journal | Thrombosis and haemostasis
(Thromb Haemost)
Vol. 105
Issue 4
Pg. 676-87
(Apr 2011)
ISSN: 2567-689X [Electronic] Germany |
PMID | 21264447
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
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Chemical References |
- Immunoglobulin Heavy Chains
- Factor VIII
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Topics |
- Adoptive Transfer
- Animals
- B-Lymphocytes
(cytology, metabolism, transplantation)
- Cell Differentiation
- Cell Lineage
- Disease Models, Animal
- Factor VIII
(genetics, metabolism)
- Genetic Therapy
- Genetic Vectors
- Hematopoietic Stem Cell Transplantation
- Hematopoietic Stem Cells
(cytology)
- Hemophilia A
(blood, genetics, therapy)
- Hemorrhage
(genetics, prevention & control)
- Humans
- Immunoglobulin Heavy Chains
(genetics)
- Lentivirus
(genetics)
- Mice
- Mice, Mutant Strains
- Promoter Regions, Genetic
- Transgenes
(genetics)
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