Foamy virus vectors: an awaited alternative to gammaretro- and lentiviral vectors.

The first vectors derived from foamy viruses were established over ten years ago. Until now only used and further developed by a handful of investigators these vectors have been shown to be promising tools for the gene transfer into haematopoietic stem cells. Several inherent features of foamy virus-derived vectors, such as the high efficiency in targeting CD34-positive stem cells, a favourable integration profile, and the apathogenic nature of the parental virus, indicate that they are superior to gammaretroviral and lentiviral vectors. The effectiveness in different preclinical animal models suggests the exploration of foamy virus vectors in human trials.