Live attenuated vaccines are among the most efficient and cost-effective vaccines that can be used to combat infectious diseases. Such vaccines either consist of natural isolates or genetically modified derivatives of wild type strains. In order to generate live attenuated vaccines for viral infectious diseases, specific techniques have to be developed that allow genetic modification of the viral genome.
Examples of viruses
At Wageningen Bioveterinary Research (WBVR) we have generated systems that can be used for precise genetic modification of many different viruses, including DNA and RNA viruses. In the tables below you can find examples of the viruses we work with.
|Single-stranded positive-sense RNA viruses|
|Classical swine fever virus (CSFV)|
|Bovine viral diarrhea virus (BVDV)|
|Porcine reproductive and respiratory syndrome virus (PRRSV)|
|Foot-and-mouth disease virus (FMDV)|
|Single-stranded negative-sense RNA viruses|
|Newcastle disease virus (NDV)|
|Influenza A virus (IAV)|
|Rift Valley fever virus (RVFV)|
|Double-stranded RNA viruses|
|Infectious bursal disease virus (IBDV)|
|Bluetongue virus (BTV)|
|African horse-sickness virus (AHSV)|
|Double-stranded DNA viruses|
|Pseudorabies virus (PRV)|
|Infectious bovine rhinotracheitis virus (IBRV)|
|Modified vaccinia Ankara (MVA)|
|Lumpy skin disease virus (LSDV)|
|African swine fever virus (ASFV)|
Reverse genetics technique
For RNA viruses genetic modification is often referred to as ‘reverse genetics’. The viral RNA genome is copied into DNA. This DNA can be used to introduce modifications to attenuate the virus or introduce other changes; after introduction of these modifications it is converted back into RNA.
For DNA viruses we use homologous recombination or CRISPR/Cas-mediated homology-dependent repair (HDR) for the precise deletion, insertion or replacement of genetic material.
Vaccines and oncolytic viro-immunotherapy
Apart from vaccine development, our expertise in reverse genetics is also being used for the generation of viruses that can be applied for oncolytic viro-immunotherapy. These viruses are derived from the Newcastle disease virus (NDV) and Rift Valley fever virus (RVFV) and are genetically modified to express therapeutic proteins, including monoclonal antibodies such as immune-checkpoint inhibitors (e.g. anti-PD1, anti-CTLA4).
Contact our expert
Please feel free to contact the expert of our Contract Research Organization (CRO) if you have a question concerning reverse genetics and reverse vaccinology.