Self-amplifying RNA vaccines
Vaccines are a triumph of medicine and science – but is the pipeline running dry? What about all those viruses we have not been able to make effective vaccines against – HIV, RSV, Ebola, etc? DNA vaccines have generally proved to be disappointing in clinical trials. This interesting new paper in PNAS suggests possible future strategies.
Nonviral delivery of self-amplifying RNA vaccines. PNAS USA 20 August2012, doi: 10.1073/pnas.12093671
Despite more than two decades of research and development on nucleic acid vaccines, there is still no commercial product for human use. Taking advantage of the recent innovations in systemic delivery of short interfering RNA (siRNA) using lipid nanoparticles (LNPs), we developed a self-amplifying RNA vaccine. Here we show that nonviral delivery of a 9-kb self-amplifying RNA encapsulated within an LNP substantially increased immunogenicity compared with delivery of unformulated RNA. This unique vaccine technology was found to elicit broad, potent, and protective immune responses, that were comparable to a viral delivery technology, but without the inherent limitations of viral vectors. Given the many positive attributes of nucleic acid vaccines, our results suggest that a comprehensive evaluation of nonviral technologies to deliver self-amplifying RNA vaccines is warranted.