Reporter Assay for Detection and Quantitation of Replication-Competent Gammaretrovirus

Gammaretroviral vectors were the first viral gene-therapy vectors to enter clinical trials and remain in use. One potential hazard associated with the use of such vectors is the presence of replication-competent retroviruses (RCR) in the vector preparations – either as a result of: 1) recombination events between the plasmids used for vector production, 2) interactions between the plasmids and endogenous retroviral sequences in the packaging cell lines, or 3) as a result of contamination in the laboratory. RCRs are potentially pathogenic and shown to induce malignancy in mice and non-human primates. Therefore, it is critical that vector preparations be rigorously tested to exclude the presence of RCRs given that the Food and Drug Administration (FDA) requires all vector preparations be screened for RCRs.At present, the FDA recommends RCR testing by inoculating an aliquot of each vector preparation into a permissive cell line and passaging the cells for at least three weeks (i.e., amplification phase). Cell-free media from the amplification phase can then be analyzed by a variety of methods to demonstrate the presence or absence of RCRs.Scientists at the National Cancer Institute (NCI) have developed a new research method for the detection of RCRs in gammaretrovirus-based gene-therapy products and the cell lines used to make them. The assay uses one of a series of DERSE (Detector of Exogenous Retroviral Sequence Elements) plasmids, stably maintained in a cell line permissive...

Source: NIH OTT Licensing Opportunities - July 7, 2020 Category: Research Authors: ott-admin Source Type: research