Published online Aug 12, 2015. doi: 10.5501/wjv.v4.i3.156
Peer-review started: February 5, 2015
First decision: April 27, 2015
Revised: June 23, 2015
Accepted: July 29, 2015
Article in press: August 3, 2015
Published online: August 12, 2015
Vaccines represent the most relevant contribution of immunology to human health. However, despite the remarkable success achieved in the past years, many vaccines are still missing in order to fight important human pathologies and to prevent emerging and re-emerging diseases. For these pathogens the known strategies for making vaccines have been unsuccessful and thus, new avenues should be investigated to overcome the failure of clinical trials and other important issues including safety concerns related to live vaccines or viral vectors, the weak immunogenicity of subunit vaccines and side effects associated with the use of adjuvants. A major hurdle of developing successful and effective vaccines is to design antigen delivery systems in such a way that optimizes antigen presentation and induces broad protective immune responses. Recent advances in vector delivery technologies, immunology, vaccinology and system biology, have led to a deeper understanding of the molecular and cellular mechanisms by which vaccines should stimulate both arms of the adaptive immune responses, offering new strategies of vaccinations. This review is an update of current strategies with respect to live attenuated and inactivated vaccines, DNA vaccines, viral vectors, lipid-based carrier systems such as liposomes and virosomes as well as polymeric nanoparticle vaccines and virus-like particles. In addition, this article will describe our work on a versatile and immunogenic delivery system which we have studied in the past decade and which is derived from a non-pathogenic prokaryotic organism: the “E2 scaffold” of the pyruvate dehydrogenase complex from Geobacillus stearothermophilus.
Core tip: Several promising strategies of vaccination have been proposed over the past years to treat and/or prevent infectious and cancer diseases. These include live attenuated or inactivated viral vaccines, recombinant viral vectors, DNA vaccines, subunit vaccines, nanoparticle carriers, and lipid-based delivery systems such as liposomes and virosomes. Although some of these suffer from certain limitations (e.g., safety concerns, weak immunogenicity, adverse side-effects associated with adjuvants), recent advances in vaccine technology have provided further insights for guiding vaccine design. Here, we review the current status of antigen delivery systems with emphasis on a versatile and immunogenic vaccine delivery candidate: the “E2 scaffold”.