Systems for gene delivery based on combination of viral and non-viral vectors

Development of new strategies for gene delivery demands improved understanding of the actions of viruses, and harnessing of their power into vectors that are safer, more fully defined and of comparable efficiency. In this chapter some of the approaches to improve the efficiency of non-viral systems for gene delivery are described, and also the strategy of polymer-modification of adenoviruses in order to decrease their immunogenicity and change their receptor-binding tropisms. Particular emphasis is placed on characterisation of the function of adenovirus hexon protein, on the use of phage display libraries to identify improved vectors targeting systems, and on the use of retargeted adenoviruses for gene delivery.