Successful transfer of ADA gene in vitro into human peripheral blood CD34+ cells by transfecting EBV-based episomal vectors.

We report a novel non-viral system for transfecting human immature hematopoietic cells in vitro. Epstein-Barr virus (EBV)-based episomal vectors carrying human adenosine deaminase (ADA) gene cDNA were transfected by electroporation into human peripheral blood (PB) CD34+ cells. The transgene-specific mRNA were detected from 37 to 100% of CFU-c (colony forming unit in culture) colonies derived from the transfected cells. A two-fold increase in enzyme activity was also found. These results indicate the successful transfer and expression of genes in human immature hematopoietic cells using the EBV-based episomal vector system.