General mechanisms of gene vaccines

Abstract

Gene vaccines have emerged as attractive alternative to conventional vaccines as they have the potential to activate both branches of the immune system, similar to live attenuated vaccines, but at a higher safety profile and with superior efficacy in production and costs. After impressive performance in small animal models, gene vaccines were quickly transferred into the clinics without detailed knowledge of the underlying molecular and immunological mechanisms. As a result, these early clinical trials led to disappointing results, nearly terminating the DNA vaccine revolution. Today, we know a lot more about vector design, uptake and processing of gene vaccines, immunostimulatory properties of DNA and RNA, and about numerous ways to modulate immune responses. Utilizing this knowledge has led to a new generation of improved vaccines and delivery modalities, and progress in the clinics is emerging. This introductory chapter will give a broad overview on the current status of gene vaccine design, their delivery and fate after introduction into the body, their immunostimulatory capacities, and finally, the processing and presentation of vaccine-encoded antigen to the immune system.