Stable gene transfer to human pluripotent hematopoietic stem cells is an attractive strategy for the curative treatment of many genetic hematologic disorders. In clinical tral, the level of gene transfer to this cell population have generally been low.

In this study we have evaluated the efficiency of gene transfer to human umbilical cord blood(UCB) CD34+cells using vesicular stomatitis virus glycoprotein G(VSV-G) pseudotyped HIV-1 vector.

High titers of replication-defective VSV-G pseudotyped HIV-1 based vector encoding the enhanced yellow fluorescent protein were produced by transient transfection. Human CD34+cells purified from UCB were incubated with pseudotyped HIV supernatants for 24-48 hours. The transduction efficiency were measured by marker gene expression under the microscopy and flow cytometry.

Transduction rates into CD34+ were low at 0 and 24 hours, reflecting 4.7±2.4% at 24 hours, they were increased to 5.7±2.7% at 48 hours.

We demonstrate efficient transduction of purified human UCB CD34+ by HIV vectors pseudotyped with VSV-G. The results extend the lentiviral vector to clinical gene therapy using human pluripotent hematopoietic stem cells.