My biosafety office is asking me about RCV (replication competent virus). What is this?
Replication competent viruses (RCV) are virus particles capable of infection and production of infectious particles. Lentiviral vectors have been engineered to significantly reduce the likelihood of RCV production.
Our lentiviral transfer plasmids are self-inactivating (SIN) vectors in which the viral enhancer and promoter have been deleted. This increases biosafety by preventing mobilization of RCV and enabling regulated expression from the internal promoter without cis-acting effects of the LTR (Miyoshi et al., J Virol. 1998). This safety measure is combined with the 2nd generation packaging system which excludes accessory viral genes necessary for efficient replication and pathogenesis in vivo. Together, these safety precautions should prevent production of RCV.However, the FDA requires that lentiviral stocks used in human clinical trials be tested for RCV, and some institutions have adopted this in their biosafety protocols. A p24 Gag antigen ELISA assay is most commonly used to demonstrate that there is no increase in p24 titer over time in the media of transduced cells. Imanis offers p24 ELISA RCV testing for lentiviruses, please see this page for more information.