Thromb Haemost 2011; 105(04): 676-687
DOI: 10.1160/TH10-11-0725
Animal Models
Schattauer GmbH

Factor VIII delivered by haematopoietic stem cell-derived B cells corrects the phenotype of haemophilia A mice

Ali Ramezani
1   Department of Anatomy and Regenerative Biology, The George Washington University, Washington, District of Columbia, USA
,
Lynnsey A. Zweier-Renn
1   Department of Anatomy and Regenerative Biology, The George Washington University, Washington, District of Columbia, USA
2   Graduate Program in Biochemistry and Molecular Genetics, The George Washington University, Washington, District of Columbia, USA
,
Robert G. Hawley
1   Department of Anatomy and Regenerative Biology, The George Washington University, Washington, District of Columbia, USA
2   Graduate Program in Biochemistry and Molecular Genetics, The George Washington University, Washington, District of Columbia, USA
› Author Affiliations

Financial support: This work was supported in part by National Institutes of Health Grants R01HL65519 and R01HL66305, and by an Elaine H. Snyder Cancer Research Award and a King Fahd Endowment from The George Washington University Medical Center.
Further Information

Publication History

Received: 14 November 2010

Accepted after major revision: 06 January 2011

Publication Date:
28 November 2017 (online)

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Summary

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 muta-genesis 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 in-duction 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.