Review of containment levels for working with replication-deficient lentiviral and gammaretroviral vectors under contained use
In 2009 COGEM issued generic advice on appropriate containment levels for laboratory activities involving lentiviral vectors derived from the Human immunodeficiency virus 1. This advice reviews the criteria used by COGEM to determine appropriate containment levels for laboratory activities. In the light of advances in understanding and the results of research commissioned by COGEM, the Commission has reviewed the criteria for activities involving replication-deficient lentiviral vectors. In its reassessment, COGEM also included consideration of activities involving replication-deficient gammaretroviral vectors derived from mouse gammaretroviruses.
COGEM is of the opinion that the production of lentiviral vectors and their use in transduction and working with cells transduced with lentiviral vectors pose a negligible risk to the environment when these activities are carried out at the minimum containment level ML-I, on the condition that there is no chance of the presence or generation of replication-competent virus (RCV) and the cells to be used do not contain any wild-type lentiviruses. Because the generation of RCV cannot be ruled out when gammaretroviral vectors are produced, COGEM advises that work with gammaretroviral vectors should continue to be carried out at containment level ML-II. COGEM considers that transduction with gammaretroviral vectors and activities involving cells transduced with gammaretroviral vectors may be carried out at containment level ML-I as long as certain conditions are met: the gammaretroviral vector batch must be free of RCV, the cell lines to be used must be of human origin and shown to be free of any replication-competent exogenous gammaretroviruses, and activities must not involve any cells which could contain gammaretroviruses.
COGEM points out that certain activities involve a risk of exposing laboratory workers to vector particles and that this exposure may lead to adverse effects in those workers. Exposure to vector particles can be prevented by carrying out the activities under working conditions and using safety equipment that are equivalent to the requirements for containment level II.