Efficient serum-free retroviral gene transfer into primitive XXXX @entity1583 progenitor cells by a defined, high-titer, nonconcentrated vector-containing medium.

@entity1 @entity6826 @entity1583 @entity2772 @entity2280
Defined serum-free conditions have great conceptual advantages for the biological safety and standardization of clinical gene transfer into @entity1583 stem cells. In the only study reported to date, Sekhar et al. achieved low serum conditions by a complex concentration procedure of a retroviral supernatant initially containing 10% fetal bovine serum. The high cost, small volume, possible coenrichment of serum-derived pathogens, limited recovery of vector particles, and low titer of the final diluted medium restrict the clinical application of this procedure. Transduction of primitive @entity1583 progenitor cells was not demonstrated. In the present study, a defined serum-free medium containing high titers of the pseudotyped retroviral vector PG13/LN was generated from PG13/LN producer cells without requiring a physical enrichment procedure. The transduction of committed @entity1583 progenitor cells in the serum-free vector-containing medium was efficient, and similar to that occurring under serum-containing control conditions. The number of primitive @entity1 @entity1583 long-term culture-initiating cell-derived colonies (LTC-IC-derived colonies) generated from @entity2280 + and @entity2280 +/HLA-DRlo peripheral blood progenitor "stem" cells (PBSCs) increased during 7 days of treatment in this vector-containing medium in the presence of @entity2772 , @entity6826 , and flt-3 ligand. The described procedure allowed efficient transduction of LTC-IC-derived colonies generated from @entity2280 +, @entity2280 +/HLA-DRlo, and @entity2280 +/CD38lo PBSCs. This is the first report to demonstrate an increase in primitive peripheral blood LTC-IC-derived colonies in vitro as well as their efficient transduction in a high-titer, serum-free vector-containing medium that can be produced exclusively from defined pharmaceutical-grade components, making it ideally suited for applications in clinical gene therapy.
