- Volume 63, Issue 2, 1982
Volume 63, Issue 2, 1982
- Animal
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Proteolytic Activation of Influenza WSN Virus in Cultured Cells is Performed by Homologous Plasma Enzymes
More LessSummaryThe effect of chick embryo allantoic fluid, porcine plasma or canine plasma on virus progeny was studied in cultured chicken, porcine and canine cells infected with influenza WSN virus. Cells incubated either without plasma or with heterologous plasma produced virions which had uncleaved haemagglutinin and low infectivity. Cells incubated with homologous plasma produced highly infectious virions with cleaved haemagglutinin. Little increase of progeny virus infectivity was observed in canine cell-porcine plasma and porcine cell-canine plasma host systems. The addition of protease inhibitors to culture containing homologous plasma, in particular ε-amino-n-caproic acid (an inhibitor of plasminogen activation), suppressed cleavage of haemagglutinin, and virions which had uncleaved haemagglutinin and low infectivity were produced by the cells. It therefore follows that haemagglutinin cleavage and activation of influenza WSN virus infectivity in cultured cells is most efficiently performed by homologous plasma proteolytic enzyme(s). The mechanism of selective plasma-mediated influenza virus proteolytic activation in homologous cells is discussed.
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Dissemination of Herpes Simplex Virus in Nude Mice after Intracutaneous Inoculation and Effect of Antibody on the Course of Infection
More LessSummaryDissemination of herpes simplex virus (HSV) in nude mice after intracutaneous inoculation in the midflank, and the effect of passively administered antibody on the course of infection were investigated. In untreated infected mice the skin lesions developed rapidly and HSV could first be recovered from the homogenate of the dorsal root ganglia on day 3 after infection, from the spinal cord on day 7 and from the brain on day 11. HSV could not be recovered from the blood, spleen or liver. In mice passively immunized with human gamma globulin, development of the skin lesions was rather slow and HSV could not be recovered from the homogenate of the dorsal root ganglia until day 16. From the results of explant culture of the ganglia, HSV was found to have reached the ganglia as early as 48 h after infection, even in mice administered human gamma globulin. The protective action of antibody seems to originate from the inhibition of virus growth not only at the inoculation site but also in the dorsal root ganglia.
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Identification of the Envelope Surface Glycoproteins of Equine Herpesvirus Type 1
More LessSummaryThe structural polypeptides of purified enveloped virions of the Army 183 strain of equine herpesvirus type 1 (EHV-1) were examined by different analytical techniques to identify the envelope glycoproteins. Glycoproteins were identified by electrophoretic analysis in polyacrylamide slab gels of virus labelled in vivo with [3H]glucosamine or labelled enzymically in vitro with either UDP-[14C]galactose or sodium [3H]borohydride. Fluorograms revealed eleven glycoproteins (mol. wt. 260000, 150000, 138000, 90000, 87000, 65000, 62000, 60000, 50000, 46000, and 24000). These glycoproteins probably correspond to virion protein (VP) 1–2, 9b, 10, 13, 14, 16, 17, 18, 21, 22a and 25 respectively, as designated in two other EHV-1 strains. In addition, a poorly resolved glucosamine-rich region (mol. wt. 250000 to 200000) corresponded to VP 3 to 8. The two isotopic surface labelling methods revealed that all the virus glycoproteins were exposed on the envelope surface.
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Immunochemical Studies of Polioviruses: Identification of Immunoreactive Virus Capsid Polypeptides
More LessSummaryInvestigation of the immunological reactions with individual poliovirus capsid polypeptides of antisera and monoclonal antibodies raised against poliovirus type 3 antigens are described. Virus polypeptides were separated by electrophoresis, transferred electrophoretically to nitrocellulose sheets and treated with antibody preparations. Antibody binding specifically to the virus polypeptides was then detected by application of 125I-labelled anti-immunoglobulin followed by autoradiography. The technique readily enabled the identification of the polypeptides recognized by the antibody. Antibodies present in polyclonal, type-specific neutralizing sera to poliovirus type 3 bound to the two largest capsid polypeptides (VP1 and VP2) of the homotypic poliovirus, and also to the VP1 of poliovirus type 1 and type 2. There was no obvious difference between the antibody binding patterns obtained with neutralizing and nonneutralizing antisera or between C-specific and D-specific antisera. VP1 appeared to be the immunodominant virus polypeptide. Among monoclonal antibodies specific for the C antigen of poliovirus type 3, a proportion reacted homotypically with the VP1 of poliovirus type 3. Other monoclonal antibodies of C antigen or D antigen specificity, or which reacted both with D and C antigens, some of which had potent virus-neutralizing activity, failed to give demonstrable binding reactions. The noncorrelation of neutralization and immunoblot reactivity suggests that sequence determinants alone do not mediate virus neutralization which may depend on antigenic determinants specified by complex conformational arrangements of the virus capsid proteins.
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Vesicular Stomatitis Virus Can Establish Persistent Infections in Syrian Hamsters
More LessSummaryPersistent infections by vesicular stomatitis virus (VSV) of the Indiana serotype were readily established in adult Syrian hamsters following intraperitoneal injection of the virus. Plaque-forming virus, identified as VSV by serological and physical criteria, was isolated from brain homogenates of five hamsters that were tested 3 to 8 months after infection. Four of these animals had exhibited either transient or permanent paralysis, whereas the fifth appeared healthy, during the period of observation. At the time of sacrifice all hamsters had high titres of anti-VSV-neutralizing antibodies in their sera.
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Mumps Virus-persistently Infected Cell Cultures Release Defective Interfering Virus Particles
More LessSummaryTwo human cell cultures, HEp-2 and L-41, persistently infected with mumps virus, produced small amounts of slowly replicating small-plaque infectious virus and detectable amounts of defective interfering virus particles which were similar to standard mumps virus in polypeptide composition, contained subgenomic size RNAs and interfered with standard mumps virus replication in susceptible cells.
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Indomethacin and Aspirin Do Not Inhibit the Antiviral or Anti-proliferative Actions of Interferon
SummaryNeither indomethacin nor aspirin, at concentrations which inhibited the formation of prostaglandins and prevented the interferon-induced increase in the intracellular concentration of cyclic GMP, had any significant effect on the development of the interferon-induced antiviral state either in mouse L1210 cells challenged with vesicular stomatitis virus or in mice infected with encephalomyocarditis virus. Furthermore, neither drug had any significant effect on the interferon-induced inhibition of cell multiplication in cultures of mouse leukaemia L1210 cells. The differences in the effects of these cyclo-oxygenase inhibitors on different interferon effects may provide some insight into the different pathways of interferon action.
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A Human Amniotic Cell Line Yielding High Titres of Human Fibroblast Interferon
More LessSummaryA line of human amniotic cells (UAC) was found to yield large amounts of fibroblast interferon (IFN-β; 100 to 150 IU/103 cells) upon induction with Newcastle disease virus (NDV). UAC cells have a doubling time of about 24 h, and do not require foetal calf serum for growth or optimal IFN yield. The IFN produced was shown to be HuIFN-β by assaying it on homologous and heterologous cells, and by neutralization tests with specific antisera. It could be purified to a specific activity of 0.6 × 107 IU/mg protein by chromatography on Blue Sepharose. Addition of 8 µg poly(A+) RNA from NDV-induced UAC in 100 µl of reticulocyte lysate resulted in the production of 510 ± 340 IU/ml of an IFN that was neutralized only by anti-HuIFN-β serum.
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A Viable Simian Virus 40 Variant with a Deletion in the Overlapping Genes for Virion Proteins VP1, VP2 and VP3
More LessSummaryNucleotide sequence analysis was used to determine the exact location of a deletion in the late region of the SP2 mutant of simian virus 40 (SV40), a viable small-plaque variant isolated from a persistent infection of rhesus monkey kidney cells. The results indicate that six base pairs are deleted from that part of the SV40 genome in which the coding regions for the three virion proteins, VP1, VP2 and VP3, overlap. This implies that all three virion proteins are affected by the deletion. This finding is discussed with respect to the viability of SP2.
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Recombinational Joints in a Simian Virus 40 Variant Generated in a Persistent Infection
More LessSummarySP1, a viable simian virus 40 (SV40) variant isolated from a persistent infection of rhesus monkey kidney cells, contains sequence rearrangements in the untranslated region of the SV40 genome which are transcribed into late mRNA leader sequences and in the region which encodes the large T antigen. Nucleotide sequences about the recombinational junctions in SP1 were determined. The sequence data show that in most instances there was not extensive homology between recombining sequences. The recombinant sequences are discussed with respect to the mechanisms by which they might have been generated.
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- Plant
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Satellite RNA in Particles of Strawberry Latent Ringspot Virus
More LessSummaryRNA from particles of isolate H of strawberry latent ringspot virus (SLRV) comprises species of mol. wt. 2.9 × 106 (RNA-1), 1.4 × 106 (RNA-2) and 0.4 × 106 (RNA-3). Isolates obtained by inoculating plants with RNA-1 plus RNA-2 lacked RNA-3, even after repeated subculturing. RNA-3 was produced when it was inoculated in mixtures with the RNA of such isolates, but not when it was inoculated alone. Most of the nucleotide sequence of RNA-3 was absent from either RNA-1 or RNA-2. RNA-3 is therefore a satellite RNA. SLRV isolates containing or lacking satellite RNA induced indistinguishable symptoms in test plants. Like the genome RNA of SLRV, satellite RNA was found to be polyadenylated and to be bound covalently to protein. Satellite RNA induced the synthesis of a 38000 mol. wt. polypeptide in rabbit reticulocyte lysates. Several properties of SLRV satellite RNA therefore resemble those of tomato black ring virus satellite RNA.
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Infection of Protoplasts from Tobacco Suspension Cultures by Tobacco Mosaic Virus
More LessSummaryProtoplasts isolated from suspension-cultured tobacco cells were inoculated with tobacco mosaic virus (TMV) using a procedure similar to that for tobacco mesophyll protoplasts. Fifty to 70% of protoplasts were infected, as determined by staining with fluorescent TMV antibody. The formation of progeny virus particles was substantiated by electron microscopy of sectioned protoplasts, and the virus yield was assessed by assaying the infectivity of protoplast extracts. The course of TMV multiplication was studied by following the incorporation of [3H]uridine into virus RNA. The results indicated that infection in this system is synchronous and that the rate of virus multiplication is comparable to that in mesophyll protoplasts. A system of undifferentiated, growing plant cells was thus established for one-step growth of TMV.
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