Viruses have proven to be one of the most efficient vehicles in transferring genetic information to eukaryotic cells. This is precisely why molecular biologists have put so much effort into modifying their genome to make them more secure (incompetent for replication, attenuation) but maintaining their ability to transfer and express recombinant genetic material. Thus, viral vectors have become a very useful tool in biomedical research both in vitro (cell cultures) and in vivo (animal experiments, gene therapy) but we must be aware that these improvements in intrinsic biosecurity of viral vectors and their commercial availability can facilitate a relaxation in the application of safe practices, circumstance that must be avoided.
Groups of viral vectors
Viruses from which the viral vectors are derived may be assigned to danger group 1 (eg adeno-associated virus, baculovirus), group 2 (eg adenovirus, herpesvirus, poxvirus) but there are also representatives to group 3 (e.g. HIV). Generally, the level of biosecurity required to work with the viral vectors is that of NCB2 but this may vary according to the proposed experimental procedure (e.g. large-scale production, animal inoculation) or the biological activity of the transgene (eg oncogene, biotoxin). ).
To correctly evaluate the risk in working with viral vectors, the following must be considered:
- the danger group of the unmodified parental virus;
- the degree of modification made to obtain the defective vector;
- the function of inactivated viral genes;
- host range and pseudotyping;
- its ability and efficiency to integrate into the genome of the host cell
- the function of the transgene.
The lab offers all research staff working with viral vectors a specific face-to-face course and informative material that can be of great help in conducting a correct risk assessment in each case. Among this material we can highlight the pathogen technical sheets (FTP), available on the intranet, and the following fact sheets:
- Viral vectors and biosecurity level
- Viral vector biosecurity level and cellular functions
- Biosecurity and viral vectors
- Biosecurity and lentiviral vectors
- Acting in case of accidental exposure to lentiviral vector