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mechanism of altered sindbis virus neurovirulence associated with a single-amino-acid change in the e2 glycoprotein.the mechanism by which amino acid changes in the e1 and e2 surface glycoproteins of sindbis virus affect neurovirulence is unknown. we have studied two recombinant viruses which differ in virulence. one (te) contains gly and the other (tes) contains arg at position 172 in e2. te causes more rapid death than tes in newborn mice. both viruses replicate similarly in nonneuronal cells, but te replicates more rapidly in the brains of newborn mice and in neuroblastoma cells. te also induces earlier vi ...19911995953
complementation between sindbis viral rnas produces infectious particles with a bipartite genome.sindbis virus, the type member of the alpha-viruses, is an enveloped virus containing a nonsegmented positive-strand rna genome. we show that the nonstructural and the structural genes can function to produce infectious virus particles when they are expressed on two different rna segments. the nonstructural genes are translated from an rna in which the structural genes have been replaced by the chloramphenicol acetyltransferase gene [xiong, c., levis, r., shen, p., schlesinger, s., rice, c. m. & ...19912014249
antiidiotypic antibodies as probes for the sindbis virus receptor.rabbit polyclonal antiidiotypic antibodies were made to mouse monoclonal antibodies that neutralize the infectivity of sindbis virus. one of the antiidiotypic antisera obtained has properties characteristic of an antireceptor antiserum. it binds to the surface of chicken cells as shown by immunofluorescence and partially blocks virus binding to these cells as determined by binding of radiolabeled virus or by a plaque reduction assay. it also immunoprecipitates a protein with a molecular weight o ...19912014644
analysis of sindbis virus promoter recognition in vivo, using novel vectors with two subgenomic mrna promoters.four types of sindbis virus vectors, each carrying two promoters for subgenomic mrna synthesis, were designed to measure relative promoter strengths and to survey potential contextual effects on promoter strengths. one of the promoters in each vector was used as the reference promoter, while the other was the one being tested. we used these vectors to measure the relative strengths of four promoters: the minimal promoter, an extended sequence believed to have full promoter activity, and two muta ...19912016769
sindbis virus infection of a chinese hamster ovary cell mutant defective in the acidification of endosomes.sindbis virus infection of a chinese hamster ovary temperature-sensitive mutant cell line defective in its ability to acidify endosomes was examined to evaluate the importance of this step in the process of alphavirus penetration of host cells by measuring the time at which viral rna synthesis was initiated. we found that rna synthesis was initiated in these mutant cells at the same time after addition of virus at either permissive or nonpermissive temperature. we conclude that exposure to the a ...19912024467
inactivation of lipid-enveloped viruses in proteins by caprylate.the use of caprylate for the inactivation of lipid-enveloped viruses in biologically active proteins both plasma derived and produced by cell culture was evaluated. viruses consisted of herpes simplex virus type i, vesicular stomatitis virus, vaccinia virus, and sindbis virus. utilizing the dissociation reaction and varying the concentration of the ionized form of caprylate, a specific amount of the nonionized form of caprylate was maintained over a wide ph range. virus-spiked protein solutions ...19912031341
deletion analysis of brome mosaic virus 2a protein: effects on rna replication and systemic spread.brome mosaic virus (bmv) genomic rna2 encodes the 94-kda 2a protein, which is one of two bmv nonstructural proteins required for rna replication and subgenomic mrna transcription. 2a contains a central polymeraselike region, which has extensive sequence similarity with the sindbis virus nsp4 and tobacco mosaic virus (tmv) 183-kda replication proteins, and also contains n- and c-terminal flanking segments without counterparts in the sindbis virus and tmv nonstructural proteins. to further investi ...19912033655
a mutant of sindbis virus with altered plaque morphology and a decreased ratio of 26 s:49 s rna synthesis in mosquito cells.when our stock of standard sindbis virus (svstd) is assayed by plaque formation on aedes albopictus mosquito cells, about 1-2% of the plaques appear much clearer and sharper than the majority of the plaques. one of these clear plaques was picked, grown into a viral stock (svcp), and used to prepare viral cdna. making use of the infectious sindbis virus plasmid, toto 1101 (rice et al., 1987), we mapped the causal mutation for the clear plaque phenotype to a region between nt 7334 and 7716, and by ...19912053283
recombination between sindbis virus rnas.the genome (49s rna) of sindbis virus is a positive-strand rna of 11.7 kb that consists of two domains. the 5' two-thirds of the rna codes for the proteins required for replication and transcription of the rna. the 3' one-third codes for the structural proteins. the latter are translated from a 26s subgenomic rna identical in sequence to the 3' one-third of the genome. the 26s rna is transcribed by initiation from an internal promoter that spans the junction between the nonstructural and structu ...19912072444
brefeldin a arrests the intracellular transport of viral envelope proteins in primary cultured rat hepatocytes and hepg2 cells.we have studied the effect of brefeldin a (bfa) on the intracellular transport of the envelope proteins of vesicular stomatitis virus (vsv) and sindbis virus in primary cultured rat hepatocytes. bfa (2.5 micrograms/ml) inhibited not only the secretion of plasma proteins into the medium, but also the assembly of both g protein of vsv and e1 and e2 proteins (envelope proteins) of sindbis virus into respective virions. concomitantly, both the acquisition of endo-beta-n-acetylglucosaminidase h resis ...19902105715
temperature sensitive shut-off of alphavirus minus strand rna synthesis maps to a nonstructural protein, nsp4.minus strand rna synthesis by the positive strand alphaviruses, sindbis and semliki forest viruses, normally occurs early in infection, is coupled to synthesis of viral nonstructural proteins and to formation of viral replication complexes, and terminates and does not occur late in infection. previously, ts24 of the a complementation group of sindbis virus rna-negative mutants was found to possess, among its other temperature sensitive defects, a temperature sensitivity in the normal cessation o ...19902136781
synthesis and processing of the nonstructural polyproteins of several temperature-sensitive mutants of sindbis virus.we have examined the synthesis and processing of nonstructural polyproteins by several temperature-sensitive mutants of sindbis virus, representing the four known rna-minus complementation groups. four mutants that possess mutations in the c-terminal domain of nonstructural protein nsp2 all demonstrated aberrant processing patterns when cells infected with these mutants were shifted from a permissive (30 degrees) to a nonpermissive (40 degrees) temperature. mutants ts17, ts18, and ts24 showed se ...19902141204
cleavage between nsp1 and nsp2 initiates the processing pathway of sindbis virus nonstructural polyprotein p123.the cleavage between nsp1 and nsp2 and that between nsp2 and nsp3 in the sindbis virus nonstructural polyproteins was studied with respect to order of processing and enzyme-substrate relationships, using site-specific mutants in which the cleavage sites had been altered. the penultimate gly in nsp1 or nsp2 or both was substituted by ala, val, or glu, and processing was studied in vitro. substitution with ala resulted in partial cleavage whereas substitution with val or glu totally abolished clea ...19902141206
cleavage-site preferences of sindbis virus polyproteins containing the non-structural proteinase. evidence for temporal regulation of polyprotein processing in vivo.the non-structural proteins of sindbis virus, nsp1, 2, 3 and 4, are produced upon cleavage of polyproteins p123 and p1234 by a proteinase residing in nsp2. we used cell free translation of sp6 transcripts to study the proteolytic activity of nsp2 and of nsp2-containing polyproteins. to generate polyprotein enzymes, a set of plasmids was made in which cleavage sites were eliminated and new initiation and termination codons introduced by in vitro mutagenesis. as a substrate, we used a polyprotein ...19902142454
phosphorylation of sindbis virus nsp3 in vivo and in vitro.nsp3 is one of four viral nonstructural proteins required for rna replication of sindbis virus. in this report, post-translational modifications of nsp3 which occur in both vertebrate and mosquito cell cultures have been examined. in pulse-chase experiments, analyzed by immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, nsp3 was initially observed as a single species (termed nsp3a, approximately 76 kda) which was gradually converted to slower mobility forms rangin ...19902145690
the characterization of ia expression during sindbis virus encephalitis in normal and athymic nude mice.to characterize the expression of ia systemically and locally on mononuclear cells during acute viral encephalitis, weanling mice were inoculated intracerebrally with sindbis virus (sv), an alphavirus. peripheral blood mononuclear cells, splenocytes and perivascular inflammatory cells in frozen brain sections were examined immunocytochemically for the presence of ia. ia expression increased in the spleen, blood and brain during sv encephalitis. the majority of the cells in the central nervous sy ...19902153758
complete sequence of the genomic rna of o'nyong-nyong virus and its use in the construction of alphavirus phylogenetic trees.the alphaviruses are a group of about 25 positive-strand rna viruses that are important human and veterinary pathogens and that are geographically dispersed. we report here the complete nucleotide sequence of the genomic rna of the alphavirus, o'nyong-nyong virus. the rna is 11,835 nucleotides in length and the organization of the genome is typical of alphaviruses. phylogenetic trees were constructed from the protein sequences of o'nyong-nyong and six other alphaviruses. trees were constructed f ...19902155505
mutations which alter the level or structure of nsp4 can affect the efficiency of sindbis virus replication in a host-dependent manner.two mutants of sindbis virus have been isolated which grow inefficiently at 34.5 degrees c in mosquito cells yet replicate normally in chicken embryo fibroblast cells at the same temperature. in addition, these mutants exhibit temperature-sensitive growth in both cell types and are rna- at the nonpermissive temperatures (k.j. kowal and v. stollar, virology 114:140-148, 1981). to clarify the basis of this host restriction, we have mapped the causal mutations for these temperature-dependent, host- ...19902159558
biochemical and physical properties of a solvent-detergent-treated fibrin glue.a fibrin glue preparation has been obtained from pooled human plasma using a procedure which includes a solvent-detergent (sd) treatment to inactivate lipid-enveloped viruses. the sd treatment inactivated greater than or equal to 5.5 log10 of hiv in less than 45 min, and greater than or equal to 5 log10 and greater than or equal to 6.5 log10 of vsv and sindbis virus, respectively, in less than 2 h. the product was found to contain high quantities of fibrinogen (116 +/- 2.49 g/l; n = 12), factor ...19902160146
[a comparative analysis of the polypeptides of the the sindbis and karelian fever viruses].in pulse-chase experiments with karelian fever virus-infected cells, proteins were found with molecular weights of 130, 98, 78, and 62 kd of which the first, second and fourth were classified as polypeptide precursors of the structural proteins of virion. the molecular weights of proteins e1, e2 and c of 52, 47 and 34 kd, respectively, as well as isoelectric points of isolated glycoproteins (pi e1 = 6.3, pi e2 = 8.4) were similar in kfv (strain leiv-9298) and sindbis virus (strain ar339). the an ...19902176422
antiviral effects of 2',5'oligoadenylates (2-5as), and related compounds.dephosphorylated "core" of 2',5'-oligoadenylate (2-5a) dimer (a2'p5'a), exogenously added to nonpermeabilized fl cells, inhibited the multiplication of sindbis virus and vesicular stomatitis virus (vsv). the compound was shown to inhibit viral protein synthesis. the addition of a2'p5'a at the early stage of viral replication was more effective than that at the late stage. in contrast with the core, phosphorylated 2-5a (p5'a2'p5'a and ppp5'a2'p5'a) and 2-5a analogs containing cordycepin (3'-deoxy ...19902178211
both amino acid changes in nsp1 of sindbis viruslm21 contribute to and are required for efficient expression of the mutant phenotype.svlm21 is a mutant of sindbis virus which in contrast to the standard virus, svstd, is able to replicate in aedes albopictus mosquito cells deprived of methionine. previously, by making use of the infectious toto plasmids, we had constructed recombinant viruses containing various svlm21 sequences, and were thereby able to map the mutations associated with the svlm21 phenotype to the gene for the nonstructural protein nsp1. two mutations were found in the nsp1 gene of svlm21. these led to predict ...19902219702
[the relationship of sindbis virus assembly and the viral protein 6k with intermediate filaments].the relationship of sindbis virus (sbv) assembly with intermediate filaments was studied by means of whole-mount and dgd embedment-free technique of em together with the procedure of gentle extraction. in the early stage of sbv infection, the "virus assembly center" was suspended in the intermediate filament network. in the late stage, the assembling and assembled virus nucleocapsids were associated with intermediate filaments. it is presumable that the virus nucleocapsids may move from the "vir ...19902270686
site-directed mutations in the sindbis virus 6k protein reveal sites for fatty acylation and the underacylated protein affects virus release and virion structure.a small hydrophobic polypeptide of 55 amino acids, noted as the 6k protein, is formed during processing of the polyprotein translated from the sindbis virus subgenomic 26 s mrna. in the accompanying paper we show that this 6k protein can be found in purified preparations of virions and that it is palmitoylated via thioester bonds with about four covalently bound fatty acids per molecule. to determine acylation sites on 6k and define a role for these fatty acids, we used site-directed mutagenesis ...19902309447
antigenic and genetic characterization of sindbis virus monoclonal antibody escape mutants which define a pathogenesis domain on glycoprotein e2.the sindbis virus mutant sb-rl, in contrast to its parent, sindbis strain ar339 (sb), is attenuated in neonatal mice, has an increased rate of penetration in tissue culture cells, and is more sensitive to neutralization by e2-specific monoclonal antibodies (mcabs) r6 and r13. these phenotypic differences are controlled by substitution of an arginine for serine at amino acid 114 of the e2 glycoprotein. to explore these relationships further, mcab r6 and r13 neutralization escape mutants of both s ...19902309450
mutagenesis of the 3' nontranslated region of sindbis virus rna.a cdna clone from which infectious rna can be transcribed was used to construct 42 site-specific mutations in the 3' nontranslated region of the sindbis virus genome. the majority of these mutations were made in the 3'-terminal 19-nucleotide conserved sequence element and consisted of single nucleotide substitutions or of small (1 to 8) nucleotide deletions. an attempt was made to recover mutant viruses after transfection of sp6-transcribed rna into chicken cells. in most cases, viable virus was ...19902319643
mutagenesis of the conserved 51-nucleotide region of sindbis virus.we have constructed 25 site-specific mutations in a domain of 51 nucleotides in sindbis virus that is highly conserved among all alphaviruses sequenced to date. these 51 nucleotides are capable of forming two hairpin structures and are found from nucleotides 155 to 205 in sindbis virus within the region encoding nsp1. of the mutations, 21 were silent and did not lead to a change in the amino acid sequence encoded. these silent mutations changed not only the linear sequence but also the stability ...19902319648
promoter for sindbis virus rna-dependent subgenomic rna transcription.sindbis virus is a positive-strand rna enveloped virus, a member of the alphavirus genus of the togaviridae family. two species of mrna are synthesized in cells infected with sindbis virus; one, the 49s rna, is the genomic rna; the other, the 26s rna, is a subgenomic rna that is identical in sequence to the 3' one-third of the genomic rna. ou et al. (j.-h. ou, c. m. rice, l. dalgarno, e. g. strauss, and j. h. strauss, proc. natl. acad. sci. usa 79:5235-5239, 1982) identified a highly conserved r ...19902319651
site-directed mutagenesis of the proposed catalytic amino acids of the sindbis virus capsid protein autoprotease.the structural proteins of sindbis virus are translated as a polyprotein precursor that is cleaved upon translation. the capsid protein is postulated to be a serine protease that releases itself from the n terminus of the nascent polyprotein by autoproteolysis. we have tested the importance in autoproteolysis of his-141, asp-147, and ser-215, previously postulated to form the catalytic triad of the protease, and of asp-163. several site-specific mutations were constructed at each of these positi ...19902335827
proteolytic dissection of sindbis virus core protein.mild trypsin treatment of the sindbis virus nucleocapsid protein yields a fragment with a molecular mass of approximately 18.5 kilodaltons with its n terminus at residue 105. the fragment, which is stable to further digestion, appears by gel exclusion chromatography to be monomeric. these data are consistent with a model for the alphavirus core proteins, consisting of an extended and flexible n-terminal arm (residues 1 to 103) and a compactly folded c-terminal domain (residues 104 to 274), as pr ...19902370686
defined mutations in the 5' nontranslated sequence of sindbis virus rna.we have constructed 24 deletion mutants which contain deletions of from 1 to 15 nucleotides in the 5' nontranslated region of sindbis virus rna and tested the effect of these mutations on virus replication. the results showed that the first 44 nucleotides, which are capable of forming a hairpin structure, are important for virus replication, as all deletions tested in this region were either lethal or resulted in virus that grew poorly in comparison to the parental virus. many of these deletions ...19902384916
attenuating mutations in glycoproteins e1 and e2 of sindbis virus produce a highly attenuated strain when combined in vitro.alterations in either the e1 or the e2 glycoprotein of sindbis virus can affect pathogenesis in animals. previously, we identified two distinct e1 glycoprotein gene sequences which differed in their effect on pathogenesis. one had an attenuation phenotype following subcutaneous inoculation of neonatal mice (e1 ala-72, gly-75, and ser-237), while the other was virulent (e1 val-72, asp-75, and ala-237). in this study, we examined the basis for this difference in pathogenesis by using a full-length ...19902384921
anchorage-dependent surface distribution and partition during freeze-fracture of viral transmembrane glycoproteins.we have compared in the same cell type the surface distribution and partition in freeze-fractured plasma membranes of sindbis virus glycoproteins in three different situations: (i) in permanently transformed cells that express the glycoproteins as the only viral product; (ii) in cells in which prebound viruses were forced to fuse with the plasma membrane by low ph treatment; (iii) in virus-infected cells. we report here that the viral proteins expressed on the surface of transfected cells show a ...19902401782
the sindbis virus 6k protein can be detected in virions and is acylated with fatty acids.a small hydrophobic polypeptide is encoded within the genome of the alphaviruses by a set of 165 nucleotides which map between the sequences for the two virus glycoproteins. this polypeptide has been referred to as 6k and was previously found on membranes in virus-infected cells. we report here that this protein is heavily acylated with long chain fatty acids covalently attached in hydroxylamine-sensitive ester bonds and that the 6k protein can be detected in purified preparations of virions. a ...19902408229
alphavirus neurovirulence: monoclonal antibodies discriminating wild-type from neuroadapted sindbis virus.wild-type sindbis virus strain ar339 (sv) and a neurovirulent mutant (nsv), derived by neonatal and weanling mouse brain passage, both cause acute fatal encephalitis in neonatal mice, but nsv alone kills adult mice. nsv cannot be distinguished from sv by immune sera or simple biochemical tests. to localize the molecular changes associated with neuroadaptation, we used a new array of 30 anti-sv monoclonal antibodies to probe for differences between sv and nsv in four tests: immunoprecipitation, e ...19852411947
characterization of sindbis virus epitopes important for penetration in cell culture and pathogenesis in animals.two anti-glycoprotein e2 monoclonal (mc) antibodies, designated r6 and r13, prepared against an attenuated mutant (sb-rl) of sindbis virus, preferentially neutralize attenuated, rapidly penetrating strains of sindbis as opposed to virulent, more slowly penetrating strains. an antigenic variant of sb-rl which displayed reduced reactivity with r6 and r13, demonstrated virulence in suckling mice and slow penetration in baby hamster kidney cells. anti-e2 mc antibodies to sb-rl and to an independentl ...19862417415
the calcium ionophore a23187 evokes and potentiates antiviral activity of interferon.calcium ionophore a23187, which causes a rapid efflux of ca2+ from cells, evokes an antiviral response in mouse lb, simian cos-1, hela, human amniotic (u), baby hamster kidney (bhk), and vero cells against sindbis (sbv) and vesicular stomatitis (vsv) viruses. the degree of antiviral activity depends on the type of cell, virus, and the dose of a23187. a23187 inhibits the production of infectious vsv; however, vsv particle production was not significantly inhibited as measured by viral rna and vir ...19852418129
interferon induction by viruses. xiv. development of interferon inducibility and its inhibition in chick embryo cells "aged" in vitro.studies with a number of viruses revealed a time-dependent acquisition of interferon (ifn) inducibility in primary chick embryo cells as they "aged" in vitro for 2-12 days at a confluent cell density without a medium change. the time-course for the development of ifn inducibility was established by generating and analyzing a family of dose (multiplicity)-response (ifn yield) curves, using newcastle disease virus (ndv, strain lasota) as the inducer. cells produced little or no ifn for the first 4 ...19852418133
cells with natural killer activity in the cerebrospinal fluid of normal mice and athymic nude mice with acute sindbis virus encephalitis.sindbis virus causes an acute, nonfatal inflammatory encephalitis in weanling balb/c mice. mononuclear inflammatory cells are present in the cerebrospinal fluid (csf) as well as in the parenchyma of the brain. both aspects of this inflammatory response were eliminated by treatment with cyclophosphamide. athymic nude (nu/nu) mice developed no inflammation in the brain, but did develop a csf pleocytosis that peaked on day 2 after infection. the time course of the appearance of cells in the csf was ...19862419416
antibody-selected variation and reversion in sindbis virus neutralization epitopes.sindbis virus variants evidencing a complex and bidirectional tendency toward spontaneous antigenic change were isolated and characterized. variants were selected on the basis of their escape from neutralization by individual monoclonal antibodies to either of the two envelope glycoproteins, e2 and e1. multisite variants, including one altered in three neutralization sites, were obtained by selecting mutants consecutively in the presence of different neutralizing monoclonal antibodies. two pheno ...19862419586
monoclonal antibody cure and prophylaxis of lethal sindbis virus encephalitis in mice.neuroadapted sindbis virus (nsv) causes acute encephalitis and paralyzes and kills adult mice unless they are treated with primary immune serum after infection. to study the nature and specificity of curative antibodies, we gave mice 30 different monoclonal antibodies (mabs) against sindbis virus (sv) 24 h after lethal intracerebral inoculation of nsv. by the time of mab treatment, nsv replication in the brain had been well established (7.5 x 10(7) pfu/g). seventeen mabs directed against multipl ...19862419592
pretreatment of human lymphocytes with interferon enhances the synthesis of interferon in cocultures with allogeneic cells.human lymphocytes pretreated with interferon (ifn) alpha, beta, or gamma produced 17 times more ifn alpha (600-10,000 units/ml) than nontreated lymphocytes when cocultivated with allogeneic cells. significant increases in ifn production (500-3,000 units/ml) were observed when lymphocytes were treated with ifn for just 2 h, and peak levels (10,000 units/ml) were produced after a 4-h treatment. the amount of ifn required to show the maximum priming effect was between 100 and 1,000 units; higher le ...19862427629
[interferon production in lymph nodes draining breast carcinoma and its augmentation by ok-432].in breast cancer patients on whom modified radical mastectomy is performed, relatively more of the regional lymph nodes draining the breast carcinoma remain in comparison with standard radical mastectomy. therefore, investigation of the functions of lymph nodes draining breast carcinoma has become important. lymphocyte subsets of 33 axillary lymph nodes from 19 breast cancer patients were analysed using flow cytometry. in axillary lymph nodes, both okt-3(+) cells and okt-8(+) cells were decrease ...19862428312
alphavirus replication in cultured cells and infected animals is inhibited by antiproteinase agents.the influence of different antiproteinase agents on alphavirus replication was examined. sindbis virus multicycle replication in cultured cells was suppressed by n-tosyl-phenylalanine chloromethyl ketone (tpck), an inhibitor of chymotrypsin-like proteinases, and by aprotinin, an inhibitor of a wide spectrum of proteinases. antiviral activity of tpck was also demonstrated in sindbis virus-infected animals. parenteral injections of tpck in infected mice reduced virus titers in brain and blood. the ...19862429615
analysis of receptors, cell surface antigens, and proteins in human melanoma cell lines resistant to human recombinant beta- or gamma-interferon.we studied the mechanisms of resistance to interferon (ifn) in two human melanoma cell lines, sk-mel-28/beta cells resistant to human recombinant beta-interferon (reifn-beta) and sk-mel-28/gamma cells resistant to human recombinant gamma-interferon (reifn-gamma). sk-mel-28/beta cells were resistant to both reifn-beta and ifn-alpha, but not reifn-gamma or natural gamma-interferon (ifn-gamma), and sk-mel-28/gamma cells were resistant to both reifn-gamma and ifn-gamma, but not reifn-beta or ifn-alp ...19862430691
translation of homologous and heterologous messenger rnas in a yeast cell-free system.a stable mrna-dependent cell-free translation system from saccharomyces cerevisiae, prepared by a modification of the method of hofbauer et al. [eur. j. biochem. 122 (1982) 199-203] was active in translation of exogenous homologous and heterologous mrnas. optimal translational activity required the addition of polyamines and yeast trna. the m transcript of the m segment of double-stranded rna, synthesized in vitro using the killer virus-associated rna polymerase, directed the synthesis of prepro ...19862433189
loss of (2'-5')oligoadenylate synthetase activity by production of antisense rna results in lack of protection by interferon from viral infections.an expression vector was constructed that carries part of the human bk papovavirus with 0.5 kilobases of (2'-5')oligoadenylate (2-5a) synthetase cdna inserted in inverted orientation downstream from the virion proteins (vp) promoter and the neomycin-resistance gene neo under the control of a simian virus 40 promoter. cells transfected with this vector and selected for resistance to the neomycin derivative g418 synthesized rna complementary to 2-5a synthetase mrna. these cells lacked 2-5a synthet ...19872433688
microcarriers as a culturing system of insect cells and insect viruses.there is an increasing interest in culturing of insect cells, which are host for arthropod-born (arbo) viruses. the potential applications of arbo viruses are in the following two main fields: 1. medical applications (e.g. preparation of viral vaccines and viral antigens for diagnostic purposes). 2. as bioinsecticides in pest control in horticulture, agriculture and forestry. one of the potential cell substrates for these applications is an anchorage-dependent-mosquito cell line established from ...19872438174
engineered defective interfering rnas of sindbis virus express bacterial chloramphenicol acetyltransferase in avian cells.we are investigating the feasibility of using the positive-strand rna virus sindbis virus and its defective interfering (di) particles as vectors for introducing foreign genes into cells. in previous work we showed by deletion mapping of a cloned cdna derived from one of the di rnas that only nucleotides at the 3' and 5' termini of the rna are essential for the di rna to be amplified after it is transfected into cells in the presence of helper virus. as a first step in developing a vector we rep ...19872440030
alternative forms of a strain-specific neutralizing antigenic site on the sindbis virus e2 glycoprotein.experiments with monoclonal antibodies raised against two laboratory strains of sindbis virus, sb and sin, suggested the existence of a strain-specific neutralizing antigenic site (e2-b) on the e2 glycoprotein. a comparison of monoclonal antibody binding patterns and e2 glycoprotein gene sequences of six laboratory strains distinguished three different configurations of e2-b that correlated with specific amino acid substitutions at position 216 of the e2 glycoprotein. further study of neutraliza ...19872445100
location of a major antigenic site involved in ross river virus neutralization.the location of a major antigenic domain involved in the neutralization of an alphavirus, ross river virus, has been defined in terms of its position in the amino acid sequence of the e2 glycoprotein. the domain encompasses three topographically close epitopes which were identified using three e2-specific neutralizing monoclonal antibodies in competitive binding assays. nucleotide sequencing of the structural protein genes of monoclonal antibody-selected antigenic variants showed that for each v ...19882448952
defective response to interferons in cells transfected with the hepatitis b virus genome.the interferon responsiveness of two cell lines transfected with the hepatitis b virus genome was investigated. a cosmid vector containing multiple copies of the hepatitis b virus genome was transfected into fl5-1 cells; it reduced their sensitivity to interferons as measured by inhibition of the cytopathic effect of sindbis virus challenge. similar vectors transfected into hela cells reduced their sensitivity to interferon as measured by production of beta 2-microglobulin. this resistance to in ...19892461895
monoclonal antibodies to the e1 and e2 glycoproteins of sindbis virus: definition of epitopes and efficiency of protection from fatal encephalitis.protection of mice from fatal neuroadapted sindbis virus encephalitis can be accomplished by passive transfer of monoclonal antibodies (mabs) to either the e1 or e2 glycoprotein of sindbis virus. both neutralizing and non-neutralizing mabs can be protective. to define further the characteristics of mabs that provide protection from fatal disease, antigenic epitopes on the e1 and e2 glycoproteins were identified using a competitive binding enzyme immunoassay. four distinct epitopes on e1 and thre ...19882462014
identification of lipid components of human serum lipoproteins involved in the inhibition of sindbis virus infectivity, hemagglutination, and hemolysis.human serum high density lipoproteins (hdl), low density lipoproteins (ldl) and very low density lipoproteins (vldl) were isolated and tested for their ability to inhibit sindbis virus infectivity, hemagglutination and hemolysis. vldl and ldl produced a strong reduction on both viral infectivity on vero cell monolayers and attachment and fusion with erythrocytes, whereas hdl appeared to be only a weak inhibitor. lipid and protein components were extracted from each class of lipoproteins to ident ...19882463824
isolation, culture and main characteristics of mouse fat-storing cells: interaction with viruses.fat-storing cells were isolated from 15-day-old mouse sinusoidal cell cultures (kupffer or endothelial cells), where they had multiplied abundantly; they were then purified by a negative selection method based on the fact that they do not possess fc receptors, as do both other types of cells. the fat-storing cells, which could be subcultured for at least 10 passages, have the main morphological characteristics already described in vivo, in particular, the rough endoplasmic reticulum and the lipi ...19892465986
most alphaviruses share a conserved epitopic region on their nucleocapsid protein.fourteen hybridoma cell lines secreting antibodies against the semliki forest virus nucleocapsid protein were established and employed for identification of conserved epitopes among 27 alphavirus types and subtypes. using an antibody capture test, the antibodies were found to cross-react to variable degree with alphaviruses belonging to the semliki forest, western encephalitis and eastern encephalitis complexes, as well as middelburg and ndumu. none of the antibodies reacted with either venezuel ...19892471798
role of the immune response in sindbis virus-induced paralysis of sjl/j mice.the pathologic role of the specific immune and inflammatory responses to viral infections of the cns was investigated by using mice which are susceptible (sjl/j) and resistant (c57bl6 and balb/c) to the development of experimental autoimmune encephalomyelitis (eae). intracerebral inoculation of 10(4) pfu of sindbis virus (sv) into 6- to 8-wk-old sjl/j mice resulted in a severe and sometimes fatal encephalomyelitis. a mild to severe hind leg paralysis was observed around days 6 to 7 postinfection ...19892472447
sulfated polysaccharides are potent and selective inhibitors of various enveloped viruses, including herpes simplex virus, cytomegalovirus, vesicular stomatitis virus, and human immunodeficiency virus.several sulfated polysaccharides (dextran sulfate, pentosan polysulfate, fucoidan, and carrageenans) proved to be potent inhibitors for herpes simplex virus, human cytomegalovirus, vesicular stomatitis virus, sindbis virus, and human immunodeficiency virus. they were moderately inhibitory to vaccinia virus but not inhibitory to adenovirus, coxsackievirus, poliovirus, parainfluenza virus, and reovirus. these results indicate that, with the exception of parainfluenza virus, enveloped viruses are s ...19882472775
abortive infection with sindbis virus of a chinese hamster ovary cell mutant defective in phosphatidylserine and phosphatidylethanolamine biosynthesis.the effects of phosphatidylserine starvation on the infection with sindbis virus (an enveloped rna virus) have been investigated in a chinese hamster ovary (cho) cell mutant (strain psa-3) which requires exogenously added phosphatidylserine for cell growth because it lacks the ability to synthesize this phospholipid. when psa-3 cells were grown in the absence of phosphatidylserine, the cellular contents of phosphatidylserine and also phosphatidylethanolamine produced through decarboxylation of p ...19892479418
the effect of interferon on cells persistently infected with hiv.in this study the effect of interferon (ifn) on uninfected cells (h9-) and cells infected (h9+) with hiv-1 was investigated. in both h9- and h9+, ifn was unable to inhibit sindbis virus replication. hiv-1 replication was inhibited by a maximum of 22% at 1000 u/ml of ifn. in both h9- and h9+ cells ifn exhibited a limited antiproliferative effect. there was activation of the 2'-5' oligo-a-synthetase (e enzyme) and the protein kinase enzyme systems, but low activation of the ribonuclease f was seen ...19892496710
mapping of rna- temperature-sensitive mutants of sindbis virus: complementation group f mutants have lesions in nsp4.temperature-sensitive (ts) mutants of sindbis virus belonging to complementation group f, ts6, ts110, and ts118, are defective in rna synthesis at the nonpermissive temperature. cdna clones of these group f mutants, as well as of ts+ revertants, have been constructed. to assign the ts phenotype to a specific region in the viral genome, restriction fragments from the mutant cdna clones were used to replace the corresponding regions of the full-length clone toto1101 of sindbis virus. these hybrid ...19892521674
mutagenesis of the in-frame opal termination codon preceding nsp4 of sindbis virus: studies of translational readthrough and its effect on virus replication.sindbis virus (sin) contains an in-frame opal termination codon in the nonstructural protein-coding region separating nsp3 and nsp4 and provides a useful tool to study the readthrough phenomenon of the termination codon in host cells and its role in viral replication. we have changed the opal codon by site-directed mutagenesis of a full-length sin cdna clone to either sense amino acids (serine, tryptophan, or arginine) or the other two translation termination codons (amber or ochre). transcripts ...19892521676
evidence that sindbis virus nsp2 is an autoprotease which processes the virus nonstructural polyprotein.the four nonstructural proteins (nsp1-4) of sindbis virus, a member of the togaviridae family, are initially expressed from the 5' segment of the single-stranded genomic (+)rna as a polyprotein which is subsequently proteolytically processed. in attempts to identify the protease acting on this nonstructural polyprotein, we established a coupled in polyprotein, we established a coupled in vitro transcription-translation system which was able to faithfully process the major polyprotein when an mrn ...19892525839
processing the nonstructural polyproteins of sindbis virus: nonstructural proteinase is in the c-terminal half of nsp2 and functions both in cis and in trans.the processing of the sindbis virus nonstructural polyprotein translated in vitro has been studied. when sindbis virus genomic rna was translated in a reticulocyte lysate, polyprotein p123 was cleaved efficiently to produce nsp1, nsp2, and nsp3. inhibition of this processing by anti-nsp2 antibodies, but not by antibodies specific for nsp1, nsp3, or nsp4, suggested that the viral proteinase was present in nsp2. to localize the proteolytic activity more precisely, deletions were made in a full-len ...19892529379
verapamil and chlorpromazine inhibit the budding of sindbis and vesicular stomatitis viruses from infected chicken embryo fibroblasts.two agents, verapamil and chlorpromazine, which affect calcium levels in cells were tested as inhibitors of sindbis and vesicular stomatitis virus replication in chicken embryo fibroblasts. at levels which did not greatly inhibit general protein synthesis, both drugs appeared to selectively block virus formation at the final stages of virus assembly and budding. viral nucleoprotein synthesis and transport of viral glycoproteins to the cell plasma membrane were not inhibited under conditions that ...19892535903
localization of epstein-barr virus envelope glycoproteins on the inner nuclear membrane of virus-producing cells.epstein-barr virus-producing cells were used as a model to analyze, with a fracture-immunolabel technique, the distribution, behavior on fracture, and extent of glycosylation of viral transmembrane glycoproteins at the inner nuclear membrane. surface and fracture immunolabeling with two monoclonal antibodies directed against the carbohydrate or polypeptide portions of the major viral envelope glycoproteins gp350/220 showed the following. (i) the glycoproteins present on the inner and outer nucle ...19892536106
susceptibility of dogs to west nile virus: a survey and pathogenicity trial.a serological survey of dogs from the highveld region of south africa showed that 37 per cent (138 of 377) had neutralizing antibodies to west nile (wn) virus and only 2.7 per cent (10 of 377) had antibodies to sindbis virus. wn virus was isolated from one of the wn-antibody negative sera. because these results suggested that dogs may play an important part in the epidemiology of wn virus, a pathogenicity trial was carried out. two of three dogs infected with wn virus had a mild recurrent myopat ...19892537346
comparison of three methods for determining transmission rates in vector competence studies with culex univittatus and west nile and sindbis viruses.culex univittatus mosquitoes were infected by ingesting west nile and sindbis viruses, respectively. after 13-19 days, comparative viral transmission rates were determined using 3 methods: 1) transmission to hamsters by bite, 2) in vitro transmission while feeding on suspensions in capillary tubes and 3) transmission while feeding on droplets of suspension. transmission rates were 59-100%, except for sindbis virus by droplet feeding when the rate was 9%. except for the latter, rates determined b ...19892540264
possible involvement of virus-induced protein kinase in the antiviral state induced with interferon-gamma against sindbis virus.the kinetics of induction of the antiviral state against two rna viruses, vesicular stomatitis virus (vsv) and sindbis virus, by human interferons (ifns)-alpha, -beta, and -gamma was measured and compared with that of 2',5'-oligoadenylate (2-5a) synthetase and protein kinase in cells treated with ifns. both enzymes were induced in similar time courses and the induction by ifn-gamma was slower than ifn-alpha or beta. the time course of the induction of antiviral state against vsv almost parallele ...19892541209
molecular pathogenesis of sindbis virus encephalitis in experimental animals.in general, the analysis of a number of strains of sindbis virus has revealed amino acid differences of potential importance for virulence at relatively few positions in the e2-glycoprotein. only 10 amino acid changes are potentially implicated, and 9 of these 10 lie in the n-terminal half of the protein (fig. 1.). currently, there is strong evidence to implicate 3 of these positions (e2-55, -114, and -172) in virulence (table v). as more recombinant viruses are prepared and analyzed, the eviden ...19892544083
palmitylation of viral membrane glycoproteins takes place after exit from the endoplasmic reticulum.palmitylation of vesicular stomatitis virus g and sindbis virus e1 glycoproteins has been studied in relation to the transport from the endoplasmic reticulum (er) to the golgi complex. incubation of infected cells at 15 degrees c prevents the transport of newly synthesized membrane proteins from the er to the golgi (saraste, j., and kuismanen, e. (1984) cell 38, 535-549). in these conditions, also palmitylation of g protein and of e1 glycoprotein is blocked. when the transport is restored by inc ...19892545712
efficient medium for impingement and storage of enveloped viruses.airborne infections with pathogenic viruses play an important role in the transmission of diseases amongst men and animals. we compared several media intended for impingement of viruses from virus-contaminated air and for their preserving effect for two enveloped viruses. sindbis (sinv) and vesicular stomatitis virus (vsv), members of the families toga- and rhabdoviridae, respectively, were chosen as indicator agents. amongst the media tested, a sampling fluid consisting of phosphate buffered sa ...19892548354
the role of monovalent cation transport in sindbis virus maturation and release.alterations in intracellular monovalent cation concentrations in sindbis virus-infected avian cells result, in part, from a reduction in na+/k+ atpase (na+ pump) activity. inhibition of na+ pump activity was shown previously to temporally correlate with the appearance of viral envelope proteins on the cell surface and the release of virus particles. cells infected with envelope-defective temperature-sensitive mutants exhibited reduced na+ pump activity at the nonpermissive temperature, where vir ...19892549721
characterization of the local and systemic b cell response of normal and athymic nude mice with sindbis virus encephalitis.during sindbis virus (sv) encephalitis in mice b cells are an important component of the mononuclear inflammatory response and recovery depends primarily on the development of antiviral antibody. to begin to characterize various parameters of the local b cell response during sv encephalitis we have defined b cell isotype expression in brain sections, splenocytes and peripheral blood mononuclear cells (pbmc) in normal and athymic nude mice using an immunoperoxidase technique. early (days 3-5) in ...19892553771
comparison of an antibody-capture igm enzyme-linked immunosorbent assay with igm-indirect immunofluorescence for the diagnosis of acute sindbis and west nile infections.the development and evaluation of an antibody-capture elisa for the detection of igm antibodies to sindbis (sin) and west nile (wn) viruses are described. comparison of the elisa results with those obtained by indirect immunofluorescence (iif) antibody tests using both fluorescein and biotinylated anti-human igm conjugates, showed that the former technique was both more sensitive and specific than the iif methods. there were no false positives by the elisa whereas with the igm-iif assays a high ...19892555380
the antiviral action of lignans.a total of 18 purified lignans was evaluated for antiviral activity against murine cytomegalovirus (cmv) and sindbis virus, by means of different treatment regimens. podophyllotoxin and alpha-peltatin were the most potent compounds, and they apparently inhibited murine cmv at an essential early step in the replication cycle after the adsorption of virus to the cells. on the other hand, justicidin b and the diphyllin derivatives were much more effective against sindbis virus, and 12 of the lignan ...19892559420
enhanced full-length transcription of sindbis virus rna by effective denaturation with methylmercury hydroxide.49-s sindbis virus rna was reverse transcribed into a complementary dna. the rna templates were denatured by three different methods prior to dna synthesis. efficient full-length transcription was only achieved after treatment with methylmercury hydroxide.19892570517
ecologic studies of mosquitoes and birds as hosts of ockelbo virus in sweden and isolation of inkoo and batai viruses from mosquitoes.field studies were conducted in central sweden from 1983 through 1985 to obtain information on the etiologic agent of ockelbo disease, described in sweden in the 1960s and probably identical to pogosta disease in finland and to karelian fever in the western ussr. mosquitoes (63,644) collected during this 3 year period yielded 21 virus strains. ockelbo virus isolations were from culiseta morsitans (5 strains), culex pipiens and/or cx. torrentium (6 strains), and aedes cinereus (3 strains). inkoo ...19892572178
evidence for specificity in the encapsidation of sindbis virus rnas.we investigated the interaction of the capsid protein of sindbis virus with sindbis viral rnas and defined a region of the genome that is required for binding in vitro and for packaging in vivo. the binding studies were performed with purified capsid protein immobilized on nitrocellulose and 32p-labeled rnas transcribed in vitro from viral and nonspecific cdnas. genomic and defective interfering (di) rnas bound capsid protein significantly better than either the subgenomic (26s) rna or nonspecif ...19892585607
svlm21, a sindbis virus mutant resistant to methionine deprivation, encodes an altered methyltransferase.the replication of sindbis virus (svstd) in cultured aedes albopictus mosquito cells is sensitive to methionine deprivation. we have suggested from earlier work that this sensitivity is primarily because of a decreased pool of s-adenosyl methionine (ado met) and the resultant failure to methylate the 5' cap of the viral mrnas. svlm21, a strain of sindbis virus derived in our laboratory from svstd by serial passage on mosquito cells maintained after infection in low concentrations of methionine, ...19892596021
properties of a highly purified human plasma factor ix:c therapeutic concentrate prepared by conventional chromatography.we have characterized a highly purified (hp) factor ix concentrate intended for therapy of hemophilia b. the product has been prepared from pooled human plasma using a large-scale procedure combining three conventional chromatographic steps based on deae ion exchange and affinity on immobilized heparin. the specific activity of the product was 119 +/- 10 iu factor ix:c/mg protein (n = 15), corresponding to a purification factor of about 9,000. the concentrate was free of the vitamin k-dependent ...19892617959
expression of sindbis virus 26s cdna in spodoptera frugiperda (sf9) cells, using a baculovirus expression vector.to study protein processing in an insect spodoptera frugiperda (fall armyworm; sf9) cell line, a 26s cdna encoding the sequence of sindbis virus structural proteins (capsid protein, of 30 kilodaltons [kda]; p62 [the precursor of e3 and e2], of 62 kda; a 6-kda peptide; and the e1 protein, of 56 kda) was inserted into the genome of autographa californica nuclear polyhedrosis virus (acnpv) adjacent to the polyhedrin promoter. by immunoblot analysis with antisera directed against whole sindbis virus ...19892644447
a cis-acting mutation in the sindbis virus junction region which affects subgenomic rna synthesis.the synthesis of sindbis virus minus-strand and genomic and subgenomic rnas is believed to require specific cis-acting sequences or structures in the template rnas and a combination of virus-specific proteins and host components which act in trans. a conserved sequence of about 21 nucleotides in the junction region and encompassing the start site for the subgenomic rna has been proposed to function as the promoter on the minus-strand template for synthesis of the subgenomic rna (j.-h. ou, c. m. ...19892685355
the proteolytic cleavage of pe2 to envelope glycoprotein e2 is not strictly required for the maturation of sindbis virus.the ionophore monensin has been shown previously to block the maturation of sindbis virus as well as prevent the cleavage of pe2 to e2 when applied to cells in high concentration. we found that a moderate dose of monensin reduced virus titer and inhibited the cleavage of pe2 to e2. under these conditions, pe2 appeared on the cell surface in a form susceptible to lactoperoxidase-mediated iodination. this pe2 was incorporated into virions, replacing e2. pe2-containing virions had a normal pfu-to-p ...19892704073
low ph-dependent sindbis virus-induced fusion of bhk cells: differences between strains correlate with amino acid changes in the e1 glycoprotein.expression of alphavirus glycoproteins on the surface of infected cells leads to cell fusion after exposure to acidic ph. two strains of sindbis virus, ar339 (sv) and neuroadapted sindbis virus (nsv), which differ in virulence for weanling mice, were found to differ in ph-dependent fusion. bhk-21 cells infected with sv fused maximally after shifting to ph 5.4, whereas cells infected with nsv required a lower ph, ph 4.8, for maximal fusion. no difference was noted in the optimal ph for agglutinat ...19892705310
intracellular transport and processing of sindbis virus glycoproteins.the intracellular transport and processing of sindbis virus envelope glycoproteins were studied in cells infected with sindbis virus using the mannose-specific enzyme, endoglycosidase h (endo h). in pulse/chase labeling experiments of hamster cells with [35s]methionine, sindbis glycoproteins pe2 and e1 became endo h resistant in two steps at 12.5 and 20.0 min after a 5-min pulse, suggesting that the glycoproteins required this period of time to be transported to the golgi compartments containing ...19892718376
mapping of rna- temperature-sensitive mutants of sindbis virus: assignment of complementation groups a, b, and g to nonstructural proteins.four complementation groups of temperature-sensitive (ts) mutants of sindbis virus that fail to make rna at the nonpermissive temperature are known, and we have previously shown that group f mutants have defects in nsp4. here we map representatives of groups a, b, and g. restriction fragments from a full-length clone of sindbis virus, toto1101, were replaced with the corresponding fragments from the various mutants. these hybrid plasmids were transcribed in vitro by sp6 rna polymerase to produce ...19892724421
association of the sindbis virus rna methyltransferase activity with the nonstructural protein nsp1.svlm21 is a mutant of sindbis virus, which in contrast to svstd, is able to replicate in aedes albopictus mosquito cells deprived of methionine. we have obtained evidence that the basis of this low methionine-resistance (lmr) phenotype is the generation of an altered rna methyltransferase with an increased affinity for s-adenosylmethionine (ado met). we now report that following the substitution of the nucleotide sequence, 126-504, from svlm21 cdna for the corresponding sequence of the toto 1101 ...19892728344
[use of probes containing cloned genes of the karelian fever virus in detecting viral genetic material in infected cells by a molecular hybridization method].two plasmid dna-probes containing dna-replicas of kfv genes (clone 1-protein e1 gene, clone 9--proteins e1 and p1 genes of kfv) were used for detection of the genetic material of karelian fever virus (kfv) in the infected cells and study of the time course of accumulation of virus-specific rnas in the process of infection. the detection was performed by the method of rna:dna dot-hybridization. both probes were hybridized with kfv and sindbis virus rna in equal amounts--5 x 10(2) infected cells a ...19892728408
sindbis virus ts103 has a mutation in glycoprotein e2 that leads to defective assembly of virions.sindbis virus mutant ts103 is aberrant in the assembly of virus particles. during virus budding, proper nucleocapsid-glycoprotein interactions fail to occur such that particles containing many nucleocapsids are formed, and the final yield of virus is low. we have determined that a mutation in the external domain of glycoprotein e2, ala-344----val, is the change that leads to this phenotype. mapping was done by making recombinant viruses between ts103 and a parental strain of the virus, using a f ...19892746736
involvement of lipids in the interaction of sindbis virus with goose erythrocytes.the chemical nature of sindbis virus receptors on goose erythrocytes was investigated by means of two different experimental approaches: by testing the capacity of human serum lipoproteins (hdl, ldl, vldl) to compete with erythrocytes for virus binding and by enzymatic and chemical modifications of the cell membrane. each class of lipoproteins was separated into its protein and lipid components which were tested for hemagglutination and hemolysis inhibiting activity. only the lipid moieties were ...19892747550
sindbis virus core protein crystals.the core protein of sindbis virus has been crystallized. three different crystal forms have been observed. they diffract variously from 2.5 a to 3.5 a resolution.19892769756
monoclonal antibodies that cross-react with the e1 glycoprotein of different alphavirus serogroups: characterization including passive protection in vivo.a panel of four monoclonal antibodies (mab) were produced that cross-react with representatives of two different togavirus serogroups, namely sindbis (sin) and semliki forest (sf) viruses, by elisa and adcmc assays. three of these mab, igg2a and igg2b isotypes, passively protected c3h/hej mice against 10 and 100 ld50 of sf challenge and one, igm, did not protect against either challenge dose, or even at 1 ld50. all these mab were cross-reactive with the e1 glycoprotein of the viruses by immunobl ...19892773592
biosynthesis, membrane translocation, and surface expression of sindbis virus e1 glycoprotein.sindbis virus glycoproteins pe2 (precursor of e2) and e1 are coded in this order by the same monocistronic mrna, cotranslationally inserted in the endoplasmic reticulum membrane and then transported to the cell surface where the progeny virus is released by budding. in the virion, three e1 plus three e2 molecules form hexameric spike complexes. previous work (s. bonatti, g. migliaccio, g. blobel, and p. walter (1984), eur. j. biochem. 140, 499-502) revealed a single signal sequence for cotransla ...19892806407
rna viruses as gene expression vectors. 19892815597
interactions of target-sensitive immunoliposomes with herpes simplex virus. the foundation of a sensitive immunoliposome assay for the virus.interactions between target-sensitive (ts) immunoliposomes and herpes simplex virus (hsv) were investigated. target sensitivity of phosphatidylethanolamine (pe) immunoliposomes is a result of the ability of acylated monoclonal anti-hsv glycoprotein d (gd) to stabilize the bilayer phase of pe, whereas by itself, pe does not form stable liposomes (ho, r. j. y., rouse, b. t., and huang, l. (1986) biochemistry 25, 5500-5506). upon binding of these immunoliposomes to hsv antigen-containing gd, destab ...19872820988
characterization of a murine cytomegalovirus-induced immunosuppressive factor.murine cytomegalovirus infection in spleen cultures resulted in the production of a soluble factor, visf (virus-induced suppressive factor), which inhibited concanavalin a mitogenesis in fresh spleen cells. its production was specific for mcmv, since infection of spleen cultures by sindbis virus, or bacteriophages pm 2 and t 4, and the phagocytosis of latex beads, all failed to elicit visf. maximum appearance of the factor occurred within 24 hours p.i. in spleen cultures, and its source was iden ...19872821959
the effect of gold sodium thiomalate in adult swiss/a2g mice infected with togaviruses and flaviviruses.treatment of adult mice with gold sodium thiomalate made the normally non-lethal semliki forest virus and sindbis virus infections lethal and increased the virulence of langat and west nile viruses. these changes were associated with an enhanced virus invasion of the brain. depression of the humoral antibody response was not observed.19872822844
differential effects of oncogenic transformation on n-linked oligosaccharide processing at individual glycosylation sites of viral glycoproteins.hamster sarcoma virus (hsv) transformation of nil-8 fibroblasts is associated with an increase in the average size of n-acetyllactosamine (complex) type n-linked glycans due to an increase in both the average number of branches/chain and in the fraction of n-linked glycans containing poly(glcnac(beta 1,3) gal-(beta 1,4)) (polylactosaminylglycan) chains. analysis of glycopeptides from the envelope glycoproteins of sindbis virus and vesicular stomatitis virus (vsv) grown in nil-8 and nil/hsv cells ...19872824491
suppression of rna synthesis by a specific antiviral activity in sindbis virus-infected aedes albopictus cells.an antiviral protein is released by mosquito cells persistently infected with sindbis virus. differences in both sensitivity to and production of this virus-specific activity were apparent in three independently produced aedes albopictus cell lines. this activity inhibits total viral rna synthesis in a time-dependent manner. the antiviral effect is maximally realized when cells are treated with the activity 48 h before infections. these data suggest that the antiviral activity induces an antivir ...19882824854
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