Janet M. Ramseur

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Extracellular murine leukemia virus (MLV) reverse transcriptase activity was decreased by interferon treatment in four interferon-sensitive mouse cell lines which were chronic MLV producers. In three cell lines which were relatively insensitive to interferon, extracellular enzyme activity remained unchanged by interferon treatment. The concentrations of(More)
A number of studies have dealt with the subject of chronic, prolonged, or persistent (the terms seem to be used interehangeably) infections of cells in culture by viruses which are, under ordinary conditions, rapidly lytie (72), and several recent workshops and meetings have been concerned with the same subject (20, 40). The reason for wide-spread interest(More)
Treatment of AKR cells that had spontaneously become procedures of a murine leukemia virus with a partially purified mouse interferon (> 5 x 10(7) international mouse reference units per mg of protein) inhibited endogenous virus production. This inhibitory effect decreased over a 72-hr period in a manner similar to interferon-induced antiviral activity(More)
Production of particles with the ultrastructural appearance of C-type virions persisted for at least 6 h in actinomycin D-treated cells infected with murine leukemia virus. This phenomenon occurred despite severe inhibition of viral RNA synthesis. Virus particles present in a 6-h harvest sedimented in sucrose gradients with the buoyant density(More)
In AKR mouse cells chronically infected with a murine leukemia virus, treatment with interferon for nine days resulted in sustained inhibition of extracellular production of murine leukemia virus but no inhibition of viral intracellular p30 antigen or of reverse transcriptase. Removal of interferon resulted in rapid reversal of these effects.(More)
Serial passage of Semliki Forest virus (SFV) in chicken embryo cells had little effect on SFV yield; however, high multiplicity infection of murine cells with one of the late passage pools (passage 9 SFV) resulted in a virus yield 10- to 20-fold lower than that obtained with earlier passage virus and 80-fold lower than the corresponding yield in chicken(More)
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