Dataset Information

A replication-competent retrovirus arising from a split-function packaging cell line was generated by recombination events between the vector, one of the packaging constructs, and endogenous retroviral sequences.

ABSTRACT: Previously we reported the presence of a replication-competent retrovirus in supernatant from a vector-producing line derived from a widely used split-function amphotropic packaging cell line. Rigorous routine screening of all retroviral stocks produced in our laboratory has not, previously or since, indicated the presence of such a virus. Replication-competent retroviruses have never previously been used in our laboratory, and stringent screening of all routinely used cell lines has not revealed the presence of any helper viruses. Therefore, it is highly unlikely that this virus represents an adventitious cross-contaminant or had been imported unknowingly with our cell line stocks. PCR studies with DNA from infected cell lines and Northern blot analysis and reverse transcriptase PCR with RNA from infected cells suggest that the helper virus arose by recombination events, at sites of partial homology, between sequences in the vector, one of the packaging constructs, and endogenous retroviral elements. These recombinations were not present in stocks of the packaging cell line or in an initial stock of the vector-producing line, indicating that these events occurred while the vector-producing line was being passaged for harvest of supernatant stocks.

SUBMITTER: Chong H

PROVIDER: S-EPMC109708 | biostudies-literature | 1998 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A replication-competent retrovirus arising from a split-function packaging cell line was generated by recombination events between the vector, one of the packaging constructs, and endogenous retroviral sequences.

Chong H H Starkey W W Vile R G RG

Journal of virology 19980401 4

Previously we reported the presence of a replication-competent retrovirus in supernatant from a vector-producing line derived from a widely used split-function amphotropic packaging cell line. Rigorous routine screening of all retroviral stocks produced in our laboratory has not, previously or since, indicated the presence of such a virus. Replication-competent retroviruses have never previously been used in our laboratory, and stringent screening of all routinely used cell lines has not reveale ...[more]

PMID: 9525583

Similar Datasets

Project description:Toca 511 (vocimagene amiretrorepvec), a nonlytic, amphotropic retroviral replicating vector (RRV), encodes and delivers a functionally optimized yeast cytosine deaminase (CD) gene to tumors. In orthotopic glioma models treated with Toca 511 and 5-fluorocytosine (5-FC) the CD enzyme within infected cells converts 5-FC to 5-fluorouracil (5-FU), resulting in tumor killing. Toca 511, delivered locally either by intratumoral injection or by injection into the resection bed, in combination with subsequent oral extended-release 5-FC (Toca FC), is under clinical investigation in patients with recurrent high-grade glioma (HGG). If feasible, intravenous administration of vectors is less invasive, can easily be repeated if desired, and may be applicable to other tumor types. Here, we present preclinical data that support the development of an intravenous administration protocol. First we show that intravenous administration of Toca 511 in a preclinical model did not lead to widespread or uncontrolled replication of the RVV. No, or low, viral DNA was found in the blood and most of the tissues examined 180 days after Toca 511 administration. We also show that RRV administered intravenously leads to efficient infection and spread of the vector carrying the green fluorescent protein (GFP)-encoding gene (Toca GFP) through tumors in both immune-competent and immune-compromised animal models. However, initial vector localization within the tumor appeared to depend on the mode of administration. Long-term survival was observed in immune-competent mice when Toca 511 was administered intravenously or intracranially in combination with 5-FC treatment, and this combination was well tolerated in the preclinical models. Enhanced survival could also be achieved in animals with preexisting immune response to vector, supporting the potential for repeated administration. On the basis of these and other supporting data, a clinical trial investigating intravenous administration of Toca 511 in patients with recurrent HGG is currently open and enrolling.

Dataset Information

A replication-competent retrovirus arising from a split-function packaging cell line was generated by recombination events between the vector, one of the packaging constructs, and endogenous retroviral sequences.

Publications

A replication-competent retrovirus arising from a split-function packaging cell line was generated by recombination events between the vector, one of the packaging constructs, and endogenous retroviral sequences.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets