Treatment of canine leukocyte adhesion deficiency by foamy virus vectors expressing CD18 from a PGK promoter

• Published in: Gene therapy Vol. 18; no. 6; pp. 553 - 559
• Main Authors: BAUER, T. R, OLSON, E. M, HUO, Y, TUSCHONG, L. M, ALLEN, J. M, LI, Y, BURKHOLDER, T. H, RUSSELL, D. W
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.06.2011
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animal diseases; Animals; Applied cell therapy and gene therapy; Biological and medical sciences; Biotechnology; CD18 antigen; CD18 Antigens - genetics; CD18 Antigens - metabolism; CD34 antigen; Dogs; Expression vectors; Foamy virus; Fundamental and applied biological sciences. Psychology; Gene expression; Gene therapy; Genetic aspects; Genetic Therapy; Genetic Vectors; Genotoxicity; Health aspects; Health. Pharmaceutical industry; Hematopoietic Stem Cell Transplantation - methods; Hematopoietic stem cells; Industrial applications and implications. Economical aspects; Integration; Kinases; Leukocyte-Adhesion Deficiency Syndrome - genetics; Leukocyte-Adhesion Deficiency Syndrome - therapy; Leukocytes (neutrophilic); Leukocytes - metabolism; Medical sciences; Models, Animal; Neutrophils - metabolism; Phosphoglycerate kinase; Phosphoglycerate Kinase - genetics; Physiological aspects; Promoter Regions, Genetic; Retroviruses; Spumavirus - genetics; Stem cell transplantation; Stem cells; Transfusions. Complications. Transfusion reactions. Cell and gene therapy; Viruses; United States; Fissipedia; Immunopathology; Carnivora; retrovirus; Stem cell; Hematopoietic cell; hematopoietic stem cell; Hemopathy; canine; Leukocyte adhesion deficiency; Immune deficiency; Foamy virus; Genetic disease; Vertebrata; Mammalia; Treatment; immunodeficiency; Gene therapy; Dog; Vector; Leukocyte disease
• ISSN: 0969-7128; 1476-5462
• DOI: 10.1038/gt.2010.169

Proto-oncogene activation caused by retroviral vector integration can cause malignancies in gene therapy trials. This has led investigators to search for less genotoxic vectors with minimal enhancer activity and a decreased risk of influencing neighboring chromosomal gene expression after integration. We previously showed that foamy virus (FV) vectors expressing the canine CD18 gene from an internal murine stem cell virus (MSCV) promoter could cure canine leukocyte adhesion deficiency (LAD). Here, we have repeated these studies using a FV vector expressing canine CD18 from a phosphoglycerate kinase (PGK) gene promoter. In vitro analysis showed that this vector did not contain an enhancer that activated neighboring genes, and it expressed CD18 efficiently in canine neutrophils and CD34+ cells. However, dogs that received hematopoietic stem cells transduced with the PGK-CD18 vector continued to suffer from LAD, and sometimes died prematurely of the disease. These studies show that the PGK promoter cannot effectively replace the MSCV promoter in CD18-expressing FV vectors, and they suggest that vectors containing a strong promoter-enhancer may be necessary for the treatment of human LAD.