title: Efficient transduction and engraftment of G-CSF-mobilized peripheral blood CD34+ cells in nonhuman primates using GALV-pseudotyped gammaretroviral vectors.
abstract: The optimal stem cell source for stem cell gene therapy has yet to be determined. Most large-animal studies have utilized peripheral blood or marrow-derived cells collected after administration of granulocyte colony-stimulating factor (G-SCF) and stem cell factor (SCF); however, SCF is unavailable for clinical use in the United States and the European Union. A recent study in a competitive repopulation assay in the rhesus macaque showed very inefficient marking of G-CSF-mobilized (G/only) peripheral blood (G-PBSC) CD34(+) cells relative to G-CSF and SCF-mobilized cells using vectors with an amphotropic pseudotype. Because G-PBSC would be the preferred target cell population for most clinical stem cell gene therapy applications, we asked whether we could achieve efficient transduction and engraftment of G-PBSC using Phoenix-GALV-pseudotyped vectors. We transplanted three baboons with G/only mobilized CD34(+) cells transduced with GALV-pseudotyped retroviral vectors. We observed high-level, persistent engraftment of gene-modified G-PBSC in all animals with gene marking levels in granulocytes up to 60%. We analyzed amphotropic (PIT2) and GALV (PIT1) receptor expression in G/only cells and found preferential expression of PIT1 after G/only, which may explain the inferior results with amphotropic pseudotypes. These findings demonstrate that high stem cell gene transfer levels can be achieved using G-CSF-mobilized PBSC with Phoenix-GALV-pseudotyped vectors.
authors.affiliation: Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Beard
authors.forename: Pau
authors.initials: P
authors.lastname: Mezquita
authors.forename: Julia C
authors.initials: JC
authors.lastname: Morris
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Kiem
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis; D005434:Flow Cytometry; D018014:Gene Transfer Techniques; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D006410:Hematopoiesis; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D017989:Leukemia Virus, Gibbon Ape / Q000235:genetics*; D010215:Papio; D011994:Recombinant Proteins; D050611:Sodium-Phosphate Cotransporter Proteins, Type III / Q000032:analysis; D014161:Transduction, Genetic
chemical_list: D018952:Antigens, CD34; D011994:Recombinant Proteins; D050611:Sodium-Phosphate Cotransporter Proteins, Type III; D016179:Granulocyte Colony-Stimulating Factor