Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:EXPT01586 (G418)
 2,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retrovirus infection is normally limited to cells within a specific host range which express a cognate receptor that is recognized by the product of the env gene. We describe retrovirus infection of cells outside of their normal host range when the infection is performed in the presence of a replication-defective adenovirus (dl312). In the presence of adenovirus, several different ecotropic vectors are shown to infect human cell lines (HeLa and PLC/PRF), and a xenotropic vector is shown to infect murine cells (NIH 3T3). Infectivity is demonstrated by 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal) staining, selection with G418 for neomycin resistance, and PCR identification of the provirus in infected cells. Infectivity is quantitatively dependent upon both the concentration of adenovirus (10(6) to 10(8) PFU/ml) and the concentration of retrovirus. Infection requires the simultaneous presence of adenovirus in the retrovirus infection medium and is not stimulated by preincubation and removal of adenovirus from the cells before retrovirus infection. The presence of adenovirus is shown to enhance the uptake of fluorescently labeled retrovirus particles into cells outside of their normal host range, demonstrating that the adenovirus enhances viral entry into cells in the absence of the recognized cognate receptor. This observation suggests new opportunities for developing safe retroviral vectors for gene therapy and new mechanisms for the pathogenesis of retroviral disease.
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PMID:Infection by retroviral vectors outside of their host range in the presence of replication-defective adenovirus. 785 30

Retroviral infection or calcium phosphate-mediated DNA transfection has been used for the generation of retrovirus producing cell lines through the introduction of vector DNA into the chromosomes of packaging cells. To compare the ability of the methods for DNA delivery to produce high-titer virus, we generated stable retroviral vector producing cell lines by the transfection or infection of a LN-based vector DNA into PA317 cells and assayed individual clones for production of virus. Of eight randomly chosen G418-resistant clones generated by transfection, only one clone produced the vector at up to > 10(7) cfu/ml. Two of the five clones generated by infection yielded higher-titer viruses in the absence of helper virus--up to 5 x 10(7) more than the transfected clones. The titer of retroviral vectors can be increased by multiple rounds of infection through long-term incubation of amphotropic virus producing cells with ecotropic virus vectors. Such amplification of vector copy number resulted in increase in vector titer of up to 20-fold. For the experiments presented here, we have used an improved vector/packaging system designed for minimizing the possibilities for the generation of an replication-competent retrovirus (RCR). However, the potential of RCR generation was detected in the culture medium harvested from the highest-titer virus producing PA317 clonal cells generated by amplification of the vector through the modified cocultivation technique, although the generation of RCR is very infrequent in the system.
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PMID:Production of high-titer retroviral vectors and detection of replication-competent retroviruses. 957 29