title: Lentivirus-mediated gene transfer into hematopoietic repopulating cells in baboons.
abstract: Efficient transduction of hematopoietic stem cells is a prerequisite for successful hematopoietic stem cell gene therapy. Oncoretroviral vectors are the most widely used vectors for hematopoietic gene therapy studies. However, these vectors require cell division, and thus efficient transduction of quiescent stem cells has been difficult to achieve. Lentiviral vectors can transduce non-dividing cells and therefore may be more efficient in transducing quiescent hematopoietic stem cells. We have used a competitive repopulation assay in the baboon to compare transduction of hematopoietic repopulating cells by lentiviral and oncoretroviral vectors. Baboon CD34-enriched marrow cells were transduced in the presence or absence of multiple hematopoietic growth factors using a short, 2-day, transduction protocol. Here, we show that efficient lentiviral transduction of hematopoietic repopulating cells was only achieved when cells were transduced in the presence of multiple growth factors. Using these conditions, up to 8.6% of hematopoietic repopulating cells were genetically modified by the lentiviral vector more than 1 year after transplant. Interestingly, the number of lentivirally marked cells increased over time in three of four animals. In conclusion, these results suggest that lentiviral vectors are able to tranduce multilineage hematopoietic stem cells, and thus, may provide an alternative vector system for clinical stem cell gene therapy applications.
authors.affiliation: Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Horn
authors.forename: J C
authors.initials: JC
authors.lastname: Morris
authors.forename: A A
authors.initials: AA
authors.lastname: Bukovsky
authors.forename: R G
authors.initials: RG
authors.lastname: Andrews
authors.forename: L
authors.initials: L
authors.lastname: Naldini
authors.forename: P
authors.initials: P
authors.lastname: Kurre
authors.forename: H-P
authors.initials: HP
authors.lastname: Kiem
mesh_terms: D000818:Animals; D018952:Antigens, CD34; D002478:Cells, Cultured; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D049452:Green Fluorescent Proteins; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000276:immunology; D016086:Lentivirus / Q000235:genetics*; D008164:Luminescent Proteins / Q000235:genetics; D023421:Models, Animal; D010215:Papio; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000494:pharmacology; D012190:Retroviridae / Q000235:genetics; D033581:Stem Cell Transplantation; D014161:Transduction, Genetic; D014182:Transplantation, Autologous
chemical_list: D018952:Antigens, CD34; D016298:Hematopoietic Cell Growth Factors; D008164:Luminescent Proteins; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins