TARGETING RETROVIRUS ENTRY

Most of the clinical gene therapy trials that have been initiated to d ate have employed ex vivo strategies in which cells are genetically mo dified outside the body and reimplanted. The ability to deliver genes accurately and efficiently to selected target cell populations in vivo would greatly expand the scope of gene therapy, but current vectors a re not well suited to this task. Here we review recent attempts to dev elop retroviral vectors incorporating engineered envelope glycoprotein s that are capable of delivering their genes in a highly specific mann er to selected human target cells.