Recombinant and chimeric viruses

Genetic engineering can be used for the production of recombinant and chimeric viruses of which the genome consists of a combination of the genetic information from two different viruses. By combining the sequences from two different viruses, the biological properties of recombinant and chimeric viruses may differ from those of the original parent strains. These changes in biological properties may be intentional – for instance to achieve changes in tropism – or unintentional. Due to our limited knowledge of the intricate interactions between viruses and their hosts, it is not always possible to faithfully predict all consequences of the new genetic constellation of recombinant and chimeric viruses. Therefore, applications involving such viruses are not completely without risk, especially when it concerns viruses which are infectious to humans. In this report different applications of recombinant and chimeric viruses are reviewed in the context of potential risks associated with the use of viruses of which the tropism has been modified either intentionally or unintentionally.