2.5. Problems related to the gene transfer methods

One of the main obstacles for successful human gene therapy continues to be the lack of optimal vector systems and, in close association with this, the lack of ultimate gene delivery methods. So far, the vectors used are immunogenic, resulting in transient expression and having deleterious effects on the recipient, or result in inefficient transduction (Otake et al. 1998). There is a need to create new, more efficient and less immunogenic vectors in conjunction with suitable surgical methods for delivering these vectors to the target tissues.