Omental implantation of BOECs in hemophilia dogs results in circulating FVIII antigen and a complex immune response.
Ex vivo gene therapy strategies avoid systemic delivery of viruses thereby mitigating the risk of vector-associated immunogenicity. Previously, we delivered autologous factor VIII (FVIII)-expressing blood outgrowth endothelial cells (BOECs) to hemophilia A mice and showed that these cells remained sequestered within the implanted matrix and provided therapeutic levels of FVIII. Prior to translating this strategy into the canine (c) model of hemophilia A, we increased cFVIII transgene expression by at least 100-fold with the use of the elongation factor 1 alpha (EF1α) promoter and a strong endothelial enhancer element. BOECs isolated from hemophilia A dogs transduced with this lentiviral vector express levels of cFVIII ranging between 1.0 and 1.5 U/mL per 10(6) cells over 24 hours. Autologous BOECs have been implanted into the omentum of 2 normal and 3 hemophilia A dogs. These implanted cells formed new vessels in the omentum. All 3 hemophilia A dogs treated with FVIII-expressing autologous BOECs developed anti-FVIII immunoglobulin G2 antibodies, but in only 2 of the dogs were these antibodies inhibitory. FVIII antigen levels >40% in the absence of FVIII coagulant function were detected in the circulation for up to a year after a single gene therapy treatment, indicating prolonged cellular viability and synthesis of FVIII.
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada; Instituto Nacional de Tecnologi do Sangue Hemocentro, University of Campinas, Campinas, São Paulo, Brazil; and.
Margareth C
MC
Ozelo
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
Barbara
B
Vidal
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
Christine
C
Brown
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
Colleen
C
Notley
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
Carol
C
Hegadorn
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
Sandra
S
Webster
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
Lori
L
Harpell
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
James
J
Ahlin
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
Andrew
A
Winterborn
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
Janine
J
Handforth
Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA.
Valder R
VR
Arruda
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
Christine
C
Hough
Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada;
David
D
Lillicrap
D000818:Animals; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D064592:Autografts; D019774:Blood Coagulation Factor Inhibitors / Q000097:blood / Q000276:immunology; D004195:Disease Models, Animal; D004285:Dogs; D042783:Endothelial Cells / Q000378:metabolism / Q000637:transplantation; D005169:Factor VIII / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006467:Hemophilia A / Q000097:blood / Q000235:genetics / Q000276:immunology / Q000628:therapy; D006801:Humans; D016086:Lentivirus; D051379:Mice; D020648:Peptide Elongation Factor 1 / Q000235:genetics; D011401:Promoter Regions, Genetic; D014161:Transduction, Genetic; D019076:Transgenes
D001323:Autoantibodies; D019774:Blood Coagulation Factor Inhibitors; D020648:Peptide Elongation Factor 1; D005169:Factor VIII