Safety aspects of insect cell culture

The hazards posed to the environment by the accidental release of baculovirus expression vectors can be put into perspective by the results obtained from experiments in which AcNPV was released deliberately into the field (Bishop et al., 1992). Polyhedrin positive viruses will persist in soil and on leaf surfaces for periods comprising weeks and months. However, polyhedrin negative viruses (similar to those used as expression vectors) do not survive in similar situations. In consequence, accidental release of baculovirus expression vectors poses negligible hazard. The risk of such a release will largely depend on the skill of the operators. This does not take into account the hazard posed by the recombinant product which is being made by the virus-infected insect cell. Synthesis of a mammalian-specific toxin, of course, would require particularly careful manipulation of the virus-infected cell culture.The fact that insect cell lines represent an undefined risk, in terms of carriage of adventitious agents means that their containment should be maintained at a minimum of the European containment level 2. Where the tissue of origin has a high risk of infection with human pathogens or where cells may have been used in a virus culture laboratory then appropriate testing is advisable. Careful risk assessment respecting the scale of work and whole procedures (in addition to individual assessment of agents and reagents) will ensure safe working conditions for laboratory staff. If applied properly safety procedures will also succeed in encouraging clean, efficient and well documented work procedures which are synonymous with the economical use of time and resources and good science.