Controlling the kinetics of interferon transgene expression for improved gene therapy

Interferon (IFN) gene based therapy has been studied for the treatment of many diseases such as viral infections, cancer and allergic diseases. Non-viral vectors, like plasmid DNA, are promising ways for delivering IFN genes, because of their low immunogenicity and toxicity compared with viral vectors. Potent therapeutic effects of IFN gene transfer will depend on the level and duration of transgene expression after in vivo administration. Therefore, controlling the kinetics of transgene expression of IFNs is a rational approach for improved gene therapy. The design and optimization of plasmid vectors, as well as their route/method of administration, is the key to obtaining high and persistent transgene expression. In this review, we aim to present experimental evidence about the relationships among the properties of plasmid vectors expressing IFNs, the kinetics of transgene expression, and therapeutic effects as well as safety issues.