Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Exposure of Aedes albopictus cells infected with Semliki Forest virus (SFV; Togaviridae) to mildly acidic pH (5.6) results in a dramatic increase in the host cell membrane permeability due to pore formation by the virus spike proteins. Identical results were obtained when the cells were infected with two other viruses, Sindbis virus (SIN, Togaviridae) and vesicular stomatitis virus (VSV, Rhabdoviridae). This permeability change could also be observed on isolated virions of SFV, SIN and VSV by measuring the influx of propidium iodide, a nucleic acid-specific fluorescent marker, into the virions. This influx was dependent on the presence of the ectodomains of the viral spikes and could be hampered by zinc ions. Furthermore, haemagglutinin, a membrane protein of influenza A virus (Orthomyxoviridae), expressed in Aedes cells induced a change in membrane permeability identical to that induced by the spike proteins of SFV, SIN and VSV when exposed to low pH. Thus acid-induced membrane permeability changes produced by spike proteins of three different virus families could be demonstrated in infected cells as well as in virions. Therefore, the low pH-induced pore formation by viral spike proteins seems to be more than an event specific for togaviruses and might well be an inherent property of enveloped viruses that use the endocytotic pathway to infect a cell.
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PMID:Low pH-induced pore formation by spike proteins of enveloped viruses. 900 93

We have developed new packaging cell lines (293SF-PacLV) that can produce lentiviral vectors (LVs) in serum-free suspension cultures. A cell line derived from 293SF cells, expressing the repressor (CymR) of the cumate switch and the reverse transactivator (rtTA2(S)-M2) of the tetracycline (Tet) switch, was established first. We next generated clones stably expressing the Gag/Pol and Rev genes of human immunodeficiency virus-1, and the glycoprotein of vesicular stomatitis virus (VSV-G). Expression of Rev and VSV-G was tightly regulated by the cumate and Tet switches. Our best packaging cells produced up to 2.6 x 10(7) transducing units (TU)/ml after transfection with the transfer vector. Up to 3.4 x 10(7) TU/ml were obtained using stable producers generated by transducing the packaging cells with conditional-SIN-LV. The 293SF-PacLV was stable, as shown by the fact that some producers maintained high-level LV production for 18 weeks without selective pressure. The utility of the 293SF-PacLV for scaling up production in serum-free medium was demonstrated in suspension cultures and in a 3.5-L bioreactor. In shake flasks, the best packaging cells produced between 3.0 and 8.0 x 10(6) TU/ml/day for 3 days, and the best producer cells, between 1.0 and 3.4 x 10(7) TU/ml/day for 5 days. In the bioreactor, 2.8 liters containing 2.0 x 10(6) TU/ml was obtained after 3 days of batch culture following the transfection of packaging cells. In summary, the 293SF-PacLV possesses all the attributes necessary to become a valuable tool for scaling up LV production for preclinical and clinical applications.
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PMID:Inducible packaging cells for large-scale production of lentiviral vectors in serum-free suspension culture. 1818 Jul 76

Lentiviral vectors persist in the host and are therefore ideally suited for long-term gene therapy. To advance the use of lentiviral vectors in humans, improvement of their production, purification, and characterization has become increasingly important and challenging. In addition to cellular contaminants derived from packaging cells, empty particles without therapeutic function are the major impurities that compromise product safety and efficacy. Removal of empty particles is difficult because of their innate similarity in particle size and protein composition to the complete particles. We propose that comparison of the properties of lentiviral products with those of purposely expressed empty particles may reveal potential differences between empty and complete particles. For this, three forms of recombinant lentiviral samples, that is, recombinant vesicular stomatitis virus glycoprotein (VSV-G) proteins, empty particles (VSV-G/Empty), and complete particles (VSV-G/SIN-GFP) carrying viral RNA, were purified by size-exclusion chromatography (SEC). The SEC-purified samples were further analyzed by immunoblotting with six antibodies to examine viral and cellular proteins associated with the particles. This study has demonstrated, for the first time, important differences between VSV-G/Empty particles and complete VSV-G/SIN-GFP particles. Differences include the processing of Gag protein and the inclusion of cellular proteins in the particles. Our findings support the development of improved production, purification, and characterization methods for lentiviral products.
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PMID:Characterization of complete particles (VSV-G/SIN-GFP) and empty particles (VSV-G/EMPTY) in human immunodeficiency virus type 1-based lentiviral products for gene therapy: potential applications for improvement of product quality and safety. 1841 16