Innovative approaches to gene therapy.

The past year has witnessed several advances in the development of targeted, cell-specific gene delivery systems of both viral and non-viral origin. Progress has been made in understanding the cellular mechanisms of nuclear import, and novel sequence-specific integrases have been developed that mediate insertion of DNA molecules into specific target sequences. Knowledge of the mechanisms by which herpes simplex virus and Epstein-Barr virus escape from immune surveillance has also advanced significantly; this may be exploited to reduce the immunogenicity of certain therapeutic gene products.