[General principles of the production and use of retroviral vectors].

This paper describes the various strategies for somatic gene therapy. There are two main scenarios: the ex vivo approach and the in vivo approach. As recombinant retroviruses were used in the first clinical trials of gene therapy, their main characteristics (structure, efficient production of helper-free viral stocks by using packaging cells, transduction procedures) are discussed as well as the related safety issues. Finally, retroviral vectors can also be used as a new tool to investigate various clinical situations as they allow to mark cells by stably integrating in the cellular genome.