Vaccines based on inactivated viruses are safe but due to their inability to trigger cellular immune responses their efficacy is often limited. Generally, live-attenuated virus vaccines are more effective, however, there is always risk left that these viruses eventually revert and regain virulence.
Our laboratory has established an RNA replicon system, which is based on a genetically modified vesicular stomatitis virus (VSV). This virus lacks the gene coding for the envelope glycoprotein G and can only be propagated on a helper cell line that provides the glycoprotein in trans. The complemented virus is infectious and efficiently delivers the RNA genome to the cytosol of various cell types. Due to the autonomous replication/transcription of the viral ribonucleoprotein complexes (the “replicon”), foreign antigens are expressed at very high levels. Like live-attenuated virus vaccines, RNA replicons trigger both the humoral and the cellular arm of the immune system and they do not rely on adjuvants. Importantly, RNA replicon vaccines are safe as they are unable to produce progeny virus (“single cycle vector“) or to regain virulence. VSV replicon vaccines have been evaluated for avian and porcine influenza viruses, bluetongue virus type 8, and porcine reproductive and respiratory syndrome virus (PRRSV).
- Federal Food Safety and Veterinary Office (grant number 1.11.15): Development of a novel marker vaccine platform for protection against African horse sickness and other orbiviruses.
- Swiss National Research Foundation (research project 310030_129669): RNA replicons addressing the requirements of high-quality influenza virus vaccines for poultry.