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antigenic analysis of tick-borne encephalitis complex viruses by time-resolved fluoroimmunoassay with monoclonal antibodies.the antigenic structure of 5 strains of tick-borne encephalitis (tbe) virus and 7 other viruses of the tbe complex was examined by the highly sensitive and specific technique of time-resolved fluoroimmunoassay (tr-fia). a collection of 8 monoclonal antibodies to the austrian strain. neudörfl, was used in this study. the findings demonstrate the uniformity of the antigenic structure of tbe viruses from different geographic regions of the ussr. in addition, an epitope was detected which is charact ...19911713917
the particle size of hepatitis c virus estimated by filtration through microporous regenerated cellulose fibre.to estimate the particle size of hepatitis c virus (hcv), a major causative agent of post-transfusion non-a, non-b hepatitis, we filtered plasma or serum samples through microporous cellulose fibres with different pore sizes. the amount of hcv particles in samples before and after filtration was determined by a quantitative reverse transcriptase polymerase chain reaction (pcr) method. since there is no quantitative biological assay for hcv, except for that in chimpanzees, the hcv titre obtained ...19911714947
the carboxy-terminal part of the ns 3 protein of the west nile flavivirus can be isolated as a soluble protein after proteolytic cleavage and represents an rna-stimulated ntpase.recently it has been reported that a membrane fraction can be isolated from west nile virus-infected bhk cells which contains the viral nonstructural (ns) proteins as major constituents (wengler et al., 1990). in this report we show that treatment of these membranes with subtilisin releases the carboxy-terminal segment of the ns 3 protein as a soluble protein of about 50 kda apparent molecular weight. this molecule, which is called the p50-s protein, can be purified by standard chromatographic p ...19911716026
the flavivirus envelope protein e: isolation of a soluble form from tick-borne encephalitis virus and its crystallization.by the use of limited trypsin digestion of purified virions, we generated a membrane anchor-free and crystallizable form of the tick-borne encephalitis virus envelope glycoprotein e. it retained its reactivity with a panel of monoclonal antibodies, and only subtle structural differences from the native protein e were recognized. treatment with the bifunctional cross-linker dimethylsuberimidate resulted in the formation of a dimer. crystallization experiments yielded hexagonal rod-shaped crystals ...19911716695
sequence of the genes encoding the structural proteins of the low-virulence tick-borne flaviviruses langat tp21 and yelantsev.the structural protein coding regions of the genomes of langat virus (strain tp21) and yelantsev virus, which was originally described to be a low virulence natural isolate of tick-borne encephalitis virus, were cloned and sequenced. these viruses had both been used as experimental live vaccines against tick-borne encephalitis in czechoslovakia and russia, respectively. peptide mapping and monoclonal antibody binding experiments yielded identical reaction patterns for langat virus and yelantsev ...19911720591
in vitro t-cell proliferative response to the flavivirus, west nile.west nile virus (wnv)-specific murine t-cell proliferation in vitro was investigated in terms of conditions that optimize antigen-specific responses and reduce background proliferation. the responder populations consisted of splenocytes from wnv-primed mice enriched for l3t4+ t cells. ia+ antigen-presenting cells (apc) were derived from splenocytes of wnv-primed or naive mice. antigen was a lysate prepared from wnv-infected vero cells at 12 h postinfection. strong virus-specific proliferative re ...19911722099
dengue surveillance in french polynesia: an attempt to use the excess number of laboratory requests for confirmation of dengue diagnosis as an indicator of dengue activity.the excess number of weekly laboratory requests for confirmation of dengue diagnosis over the expected number of requests forecasted by the modified serfling method is proposed for the surveillance of dengue in french polynesia, in addition to conventional methods. retrospective analysis of the seasonal curves of dengue activity related to the number of laboratory requests is described for the years 1982-1987 where dengue type 4 was the only active flavivirus at the time when the forecast was in ...19911783054
[preliminary study on the presence of arbovirus in the populations of corrientes and misiones].human seroprevalence of flavivirus was determined by hemagglutination inhibition tests on 479 sera from misiones and 49 from corrientes provinces. paraná and uruguay river bank communities from argentina and neighbouring countries carry out frequent traffic across the rivers. with the aim of searching for a possible introduction of dengue virus from brasil or/and paraguay, reactivity among people from paraná and uruguay river communities was compared with those from mountain communities. two ser ...19911815271
the sensitivity of cell-associated dengue virus proteins to trypsin and the detection of trypsin-resistant fragments of the nonstructural glycoprotein ns1.extracts of vero cells infected with dengue virus type 2 were digested by trypsin in the presence and absence of detergents. the experiments were designed to test the models proposed for flavivirus translation in which the glycoproteins prm, e, and ns1 are inserted into the endoplasmic reticulum of the cell, whereas certain other nonstructural proteins are not. viral polypeptides were detected by the use of radiolabel, by immunoprecipitation, or by immunoblotting. the results obtained for ns3 an ...19911824904
in vitro synthesis of west nile virus proteins indicates that the amino-terminal segment of the ns3 protein contains the active centre of the protease which cleaves the viral polyprotein after multiple basic amino acids.a virus-encoded protease that cleaves after multiple basic amino acid residues has been implicated in the processing of the flavivirus polyprotein. recently, a computer search of amino acid residues which might form the active site of a protease led to the suggestion that the amino-terminal segment of the ns3 protein represents a serine protease. to examine this possibility we constructed an mrna which encodes a polyprotein with an amino-terminal signal sequence derived from the influenza virus ...19911826736
glycosylation and secretion of yellow fever virus nonstructural protein ns1.the flavivirus genome codes for structural and nonstructural proteins which are produced from a common polyprotein precursor by proteolytic processing. the nonstructural protein ns1 is hypothesized to be involved in virus assembly and maturation as well as in protective immunity. this paper describes the synthesis of several forms of yellow fever (yf) virus ns1 protein during virus cultivation in vitro. these include cell-associated and secreted ns1 forms, the major difference among these being ...19911828321
t-helper cell and associated antibody response to synthetic peptides of the e glycoprotein of murray valley encephalitis virus.a battery of 16 synthetic peptides, selected primarily by computer analysis for predicted b- and t-cell epitopes, was prepared from the deduced amino acid sequence of the envelope (e) glycoprotein of murray valley encephalitis (mve) virus. we examined all of the peptides for t-helper (th)-cell recognition and antibody induction in three strains of mice: c57bl/6, balb/c, and c3h. lymphoproliferative and interleukin-2 assays were performed on splenic t cells from mice inoculated with peptides in f ...19911832722
processing of the yellow fever virus nonstructural polyprotein: a catalytically active ns3 proteinase domain and ns2b are required for cleavages at dibasic sites.the vaccinia virus-t7 transient expression system was used to further examine the role of the ns3 proteinase in processing of the yellow fever (yf) virus nonstructural polyprotein in bhk cells. yf virus-specific polyproteins and cleavage products were identified by immunoprecipitation with region-specific antisera, by size, and by comparison with authentic yf virus polypeptides. a yf virus polyprotein initiating with a signal sequence derived from the e protein fused to the n terminus of ns2a an ...19911833562
variable and hypervariable domains are found in the regions of hcv corresponding to the flavivirus envelope and ns1 proteins and the pestivirus envelope glycoproteins.based on the flavi- and pestivirus model of genome organization for the hepatitis c virus (hcv) (1-5), the nucleotide and deduced amino acid sequences of the putative envelope (e1) and the junction between the e1 and ns1/envelope 2 (e2) region from six different human isolates of hcv were compared with the nucleotide and predicted amino acid sequences of the prototype hepatitis c virus (hcv-1) (5). the overall percentage of nucleotide and amino acid changes among all six isolates, including hcv- ...19911846505
the relationship between the flaviviruses skalica and langat as revealed by monoclonal antibodies, peptide mapping and rna sequence analysis.the flavivirus skalica was isolated from a bank vole in czechoslovakia in 1976. it can be serologically distinguished from prototype strains of tick-borne encephalitis (tbe) virus and has a decreased virulence for adult mice. we have further defined the relationship of skalica virus to other members of the tbe serocomplex (tbe european and far eastern subtypes, langat and louping ill virus) by using a panel of 22 monoclonal antibodies, peptide mapping and rna sequence analyses. by these criteria ...19911847173
persistent infection of vero cells by the flavivirus murray valley encephalitis virus.murray valley encephalitis (mve) virus strain or2 was serially passaged on vero cells to establish a persistent infection which was maintained for over 300 days. supernatants from infected cells protected vero cells from c.p.e. and caused up to a 95% reduction of wild-type virus yield. these protective and interfering effects suggest that defective interfering (di) particles are responsible for the establishment and maintenance of the mve virus persistent infection. the persistently infected cel ...19911848592
molecular structure of the japanese hepatitis c viral genome.the amino acid sequence of the polyprotein deduced from the nucleotide sequence of the japanese hepatitis c virus genome (n. kato et al. (1990) proc. natl. acad. sci. usa 87, 9524-9528) indicated that this virus is a member of a new class of positive-stranded rna viruses. several domains of this polyprotein also showed weak homology with those of flaviviruses and pestiviruses including the chymotrypsin-like serine proteinase, ntpase and rna-dependent rna polymerase.19911849488
production of dimer-specific and dengue virus group cross-reactive mouse monoclonal antibodies to the dengue 2 virus non-structural glycoprotein ns1.a panel of mouse monoclonal antibodies (mabs) raised against the non-structural glycoprotein ns1 of dengue 2 virus (pr159) was studied for cross-reactivity with the ns1 protein of other dengue virus serotypes and other members of the flaviviridae using immunoblotting. most of the 35 anti-ns1 mabs were found to be specific for dengue 2 virus ns1 (some of which were specific for the native, dimeric form of this protein), but others were found to cross-react within the dengue virus group. this latt ...19911849979
development of cross-reactive antibodies to plasminogen during the immune response to dengue virus infection.the four serotypes of dengue virus (a mosquito-borne flavivirus) cause an acute febrile illness (dengue fever) or a more prolonged illness with plasma leakage resulting in hypovolemia (dengue hemorrhagic fever). hemorrhage may accompany either. epidemiologic data suggest a role for dengue antibodies in pathogenesis. computer analysis revealed a 20-residue region of similarity in amino acid sequence between the dengue type 4 envelope glycoprotein (e) and a family of clotting factors, including pl ...19911856477
in vitro homotypic and heterotypic interference by defective interfering particles of west nile virus.defective interfering (di) particles of the flavivirus west nile (wn) were generated after as few as two high multiplicity serial passages in vero and llc-mk2 cells. six cell lines (vero, llc-mk2, l929, hela, bhk-21 and sw13) were used to assay interference by di particles in a yield reduction assay. interference was found to vary depending on the cell type used. the highest levels of interference were obtained in llc-mk2 cells, whereas no detectable effect was observed in bhk-21 and sw13 cells. ...19911940867
murray valley encephalitis acquired in western australia.to report a recent fatal case of encephalitis associated with evidence of murray valley encephalitis virus infection, only the second fatality from this infection in western australia.19911645843
flavivirus type-specific antigens produced from fusions of a portion of the e protein gene with the escherichia coli trpe gene.based on previous data showing that jev and den-1 fusion proteins can be used as antigens, we engineered analogous fusion proteins for the same regions of the e proteins of den-2, den-3, and den-4, using the polymerase chain reaction. the resulting fusion proteins were tested in a modified elisa for their reactivity with mouse immune ascitic fluids (miaf) generated against 10 different flaviviruses. the results showed that these recombinant antigens could be used as type-specific immunological r ...19911648310
immunoaffinity purification of the ns1 protein of murray valley encephalitis virus: selection of the appropriate ligand and optimal conditions for elution.a novel approach was used to select the most suitable antiviral monoclonal antibody (mab) and elution conditions for immunoaffinity purification of the ns1 protein of murray valley encephalitis virus (mve). crude ns1 protein was subjected to a variety of chemical conditions produced by common elution buffers, and tested with a panel of ns1-specific mabs by elisa to determine which buffers denatured antigenic epitopes. buffers that caused least structural damage to ns1 epitopes were tested by eli ...19911648569
sequencing the termini of capped viral rna by 5'-3' ligation and pcr. 19911651093
monoclonal antibodies to kunjin and kokobera viruses.five monoclonal antibodies (moab) were produced to the envelope (e) protein of kunjin (kun) virus. three of these were specific for the kun/west nile complex, and two reacted with epitopes that were common to the flavivirus family. these moab defined at least four distinct epitopes on the e protein of kun virus. eight moab were also produced to unidentified proteins of kokobera (kok) virus. seven were specific for kok, while the remaining antibody cross-reacted with stratford virus and an unregi ...19911651286
flavivirus enzyme-substrate interactions studied with chimeric proteinases: identification of an intragenic locus important for substrate recognition.the proteins of flaviviruses are translated as a single long polyprotein which is co- and posttranslationally processed by both cellular and viral proteinases. we have studied the processing of flavivirus polyproteins in vitro by a viral proteinase located within protein ns3 that cleaves at least three sites within the nonstructural region of the polyprotein, acting primarily autocatalytically. recombinant polyproteins in which part of the polyprotein is derived from yellow fever virus and part ...19911651406
hepatitis c virus: an overview.in may 1988, kuo and houghton and their colleagues in chiron research laboratory, in cooperation with the physicians from nih and cdc, announced their discovery of the agent which is responsible for the majority of non-a non-b hepatitis (nanb) in post-transfusion hepatitis (pth)1,2, concluding a 15-year effort to search for this elusive agent. although it is believed that there is another blood-borne agent responsible for a smaller percentage of the post-transfusion hepatitides, the new agent (a ...19911655677
recurrent outbreaks of japanese encephalitis in nagaland (1985-1989)--a seroepidemiological study.recurrent epidemics of encephalitis in nagaland, a north-eastern state of india, following its first appearance in 1985, were investigated both epidemiologically and virologically. although, no viral agent could be isolated from any of the clinical samples and mosquitoes, detection of je specific igm antibodies in many of the csf and acute blood samples, together with presence of hi and cf antibodies to je antigen in a number of acute and convalescent sera established the etiologic role of je vi ...19911655865
hepatitis c virus: buoyant density of the factor viii-derived isolate in sucrose.physicochemical and molecular characterization studies of hepatitis c virus (hcv), the major causative agent of parenterally transmitted non-a, non-b hepatitis (pt-nanbh), strongly suggest that it is a pesti-/flavivirus-like virus. additional studies show that the buoyant density of plasma-derived hcv in sucrose is significantly lower than that of most tissue culture-derived flaviviruses (1.20 g/cm3). our finding suggests, but does not prove, that at least one physicochemical property of hcv is ...19911655970
prevalence of antibodies to hepatitis c virus (anti-hcv) in different populations in taiwan.the prevalence of antibodies to hepatitis c virus (anti-hcv) was investigated among different populations in taiwan, where anti-hcv was detected in 0.8% (24/2,994) of adult volunteer blood donors, 0.1% (1/1,305) of youngsters and children, 12.5% (8/64) of adult volunteer blood donors with elevated alanine aminotransferase (alt), 36.5% (23/63) of hemodialysis patients, 4.1% (13/318) of male homosexuals, 25.4% (16/63) of cases positive for antibodies to human immunodeficiency virus (anti-hiv), 82. ...19911657545
seroepidemiology of arboviruses among seabirds and island residents of the great barrier reef and coral sea.duplicate neutralization tests were done on 401 avian and 101 human sera from island residents collected in the coral sea and on australia's great barrier reef against 19 known arboviruses. antibodies to a potentially harmful flavivirus, gadget's gully virus, were equally present (4%) in both avian and human sera. antibodies to another flavivirus, murray valley encephalitis, and an ungrouped isolate, csiro 1499, were also present in both populations with non-significantly different incidences. a ...19911657626
genetic selection of a flavivirus-refractory strain of the yellow fever mosquito aedes aegypti.two inbred (isofemale) aedes aegypti mosquito lines were derived that manifested a resistant or susceptible phenotype following ingestion of yellow fever virus; lack of virus movement from the midgut defined the resistant phenotype. other flaviviruses, including dengue 1-4, uganda s, and zika, viruses behaved in a similar fashion in the two mosquito lines. crosses between the two lines produced progeny that were of intermediate susceptibility, indicating codominance; f2 backcrosses to the parent ...19911659238
detection of immobilised murray valley encephalitis virus rna using oligonucleotide probes with varying degrees of mismatch.the design of oligonucleotides used for hybridisation studies often utilises available sequence information of the type strain of a particular virus. if hybridisation studies, using such oligonucleotides, are carried out with field isolates of the same virus, the problem of base pair mismatches and consequent difficulties in detection may arise. this study examined the effect of base pair mismatches on the hybridisation between membrane-bound murray valley encephalitis virus (mve) rna derived fr ...19911660491
detection of stable secondary structure at the 3' terminus of dengue virus type 2 rna.the 3'-terminal sequences of flavivirus genomes within approx. 100 nucleotides (nt) have been suggested to have a highly conserved secondary structure, as based on the known nt sequence data and free-energy calculations using computer programs. to test the existence of a secondary structure in solution, we devised a strategy to generate truncated rna molecules from about 0.3-1.4 kb in length, having the same polarity and nt sequence as dengue virus type 2 (den-2) rna (new guinea-c strain). when ...19911660836
[virus replication and protein processing: flavivirus specific protease]. 19911663638
[the identification of flaviviruses by using highly specific immunoenzyme analysis]. 19911664561
synthetic deoxyoligonucleotide probes for identification of flaviviruses. 19911668693
prevention of flavivirus encephalitides in travellers to endemic areas. 19911669777
nuclear immunofluorescence in porcine kidney cells infected with japanese encephalitis virus.acetone-fixed porcine stable kidney (ps) cells infected with japanese encephalitis (je) virus were stained in indirect fluorescent antibody (fa) assay with anti-je virus monoclonal (moab) and polyclonal (immune pf) antibodies. first positive immunofluorescence (if) occurred in the cytoplasm with moab hs-1 (anti-envelope, je-specific) and immune pf after 7 hr post-infection (p. i.); it became prominent by 15 hr to 48 hr (maximum) when cells reacted strongly also with moab hx-3 (flavivirus crossre ...19911683134
the complex of flavivirus envelope polypeptide with meningococcal proteosomes elicits formation of virus-neutralizing antibodies.polypeptide e of tick-borne encephalitis virus was isolated in sucrose density gradient and mixed with equal weight portion of meningococcal proteosomes in the presence of n-dodecyl-n,n-dimethylglycine. mutual complexing of viral and bacterial molecules occurred after removal of detergent by dialysis. complexed particles appeared in the electron microscope as 40-50 microns thick short-rod structures covered on their surface with both, delicate poppy-like grains, or envelope subunit-like clustere ...19911686957
the effect of chloroquine prophylaxis on yellow fever vaccine antibody response: comparison of plaque reduction neutralization test and enzyme-linked immunosorbent assay.weekly oral chloroquine prophylaxis for malaria has been associated with impaired antibody response to intradermal rabies vaccination. experimental data indicate that chloroquine may inhibit yellow fever virus in vitro, yet there has been no clinical evidence to suggest that antibody response to yellow fever vaccine is impaired by concomitant oral administration of chloroquine. a prospective trial was undertaken to evaluate the antibody response to yellow fever 17d vaccine (connaught laboratorie ...19911996743
both nonstructural proteins ns2b and ns3 are required for the proteolytic processing of dengue virus nonstructural proteins.the cleavages at the junctions of the flavivirus nonstructural (ns) proteins ns2a/ns2b, ns2b/ns3, ns3/ns4a, and ns4b/ns5 share an amino acid sequence motif and are presumably catalyzed by a virus-encoded protease. we constructed recombinant vaccinia viruses expressing various portions of the ns region of the dengue virus type 4 polyprotein. by analyzing immune precipitates of 35s-labeled lysates of recombinant virus-infected cells, we could monitor the ns2a/ns2b, ns2b/ns3, and ns3/ns4a cleavages ...19912016768
ph-dependent fusion of tick-borne encephalitis virus with artificial membranes.ph-dependent fusion of tbe virus with artificial membranes was effective at slightly acidic ph with maximum at 6.4. the influence of various changes in e protein conformation on fusion process was studied.19912048972
infectious rna transcribed from stably cloned full-length cdna of dengue type 4 virus.dengue virus is an enveloped positive-strand rna virus with a genome approximately 11 kilobases in length. the four serotypes of dengue virus are currently the most important members of the flavivirus family in terms of geographical distribution and the incidence of infection in humans. in this communication we describe successful cloning of a stable full-length cdna copy of dengue type 4 virus that can be used as the template for in vitro transcription of infectious rna. evidence is presented t ...19912052593
adjuvant effect of human growth hormone with an inactivated flavivirus vaccine.vaccines made by inactivating pathogenic microorganisms have been dramatically successful in controlling diseases in humans and animals. despite their successes, they have a major disadvantage in that several inoculations are required for them to be effective. to overcome this problem, a commercial inactivated vaccine preparation against tickborne encephalitis was combined with human growth hormone (hgh). this formulation produced complete protection in a murine model with only one dose of vacci ...19912056204
processing of dengue virus type 2 structural proteins containing deletions in hydrophobic domains.the 5' end of the genome of the dengue virus type 2 encoding the structural proteins was expressed using recombinant vaccinia virus. three additional recombinants derived by deletion of selected dengue sequences within the parental construct were also expressed. they were designed to assess the role of hydrophobic domains in the processing of the viral polyprotein in intact cells. the first construct contained a deletion of nucleotides encoding most of the c protein; nucleotides encoding the hyd ...19921729986
recombinant vaccinia virus producing the prm and e proteins of yellow fever virus protects mice from lethal yellow fever encephalitis.four recombinant vaccinia viruses were constructed for expression of different portions of the 17d yellow fever virus (yfv-17d) open reading frame. a recombinant, vp869, expressing prm and e induced high titers of neutralizing and hemagglutination inhibiting antibodies in mice and was protective against intracranial challenge with the french neurotropic strain of yfv. levels of protection were equivalent to those achieved by immunization with the yfv-17d vaccine virus. recombinant vaccinia virus ...19921736531
the murray valley encephalitis virus prm protein confers acid resistance to virus particles and alters the expression of epitopes within the r2 domain of e glycoprotein.to study the role of the precursor to the membrane protein (prm) in flavivirus maturation, we inhibited the proteolytic processing of the murray valley encephalitis (mve) virus prm to membrane protein in infected cells by adding the acidotropic agent ammonium chloride late in the virus replication cycle. viruses purified from supernatants of ammonium chloride-treated cells contained prm protein and were unable to fuse c6/36 mosquito cells from without. when ammonium chloride was removed from the ...19921280384
[arbovirus antibodies in wild game caught in moravia].the hit method was used to examine blood serums of the game in moravia (roebuck, red deer, fallow deer, mouflon, wild boar, brown hare) for the presence of antibodies to arboviruses of these groups: alphavirus (sindbis-sin), flavivirus (west nile-wn), tick-borne encephalitis (tbe) and bunyamwera (tahyna-tah, calovo-cvo). antibodies to all viruses were detected, and namely in these frequencies: sin 0.9%, wn 16.9%, tah 41.5%, cvo 23.1% and tbe 8.5%.19921292172
[early summer meningoencephalitis vaccination. the indications and a critical assessment of the neurological vaccination complications]. 19921309694
comparison of a dengue-2 virus and its candidate vaccine derivative: sequence relationships with the flaviviruses and other viruses.a comparison of the sequence of the dengue-2 16681 virus with that of the candidate vaccine strain (16681-pdk53) derived from it identified 53 of the 10,723 nucleotides which differed between the strains. nucleotide changes occurred in genes coding for all virion and nonvirion proteins, and in the 5' and 3' untranslated regions. twenty-seven of the nucleotide changes resulted in amino acid alterations. the greatest amino acid sequence differences in the virion proteins occurred in prm (2.20%; 2/ ...19921312269
hepatitis c: basic and clinical studies.the hcv, a single stranded rna virus belonging to the family of flavivirus, has been identified as the probable cause of the majority of cases of transfusion-associated nanb hepatitis and community-acquired nanb hepatitis in japan. the hepatitis virus is present in a least 2% of the blood donor population and is extremely common in high risk groups, such as hemophiliacs and hemodialysis patients. the contribution of hcv infection to sporadic, acute and chronic hepatitis, liver cirrhosis and prim ...19921313382
virus safety of human immunoglobulins: efficient inactivation of hepatitis c and other human pathogenic viruses by the manufacturing procedure.human immunoglobulins are plasma derivatives with a low risk of transmitting viral infections. to the present, no proven case of human immunoglobulins transmitting human immunodeficiency viruses has been reported. however, there have been a few reports on the transmission of hepatitis c virus by these plasma proteins. to improve further the safety of both 5s iv human immunoglobulins and 7s im immunoglobulins, we introduced a 10-hour heat treatment of the aqueous solutions at 60 degrees c (i.e., ...19921314286
immunogenicity of experimental live attenuated japanese encephalitis vaccine viruses and comparison with wild-type strains using monoclonal and polyclonal antibodies.a total of 105 hybridomas secreting anti-japanese encephalitis (je) virus monoclonal antibodies (mabs) were generated from six fusions against four strains of je virus: wild-type strains sa14 and g8924 and live attenuated vaccines sa14-5-3 and sa14-14-2 (pdk-9). most of the mabs (87%) elicited haemagglutination inhibition activity while only a minority (24%) elicited neutralization. none of the mabs prepared against sa14-5-3, parent of sa14-14-2, elicited neutralization while the only mabs prepa ...19921315470
cloning and sequence analysis of the genes encoding the nonstructural proteins of langat virus and comparative analysis with other flaviviruses.langat virus, a member of the family flaviviridae is antigenically very similar to highly pathogenic tick-borne encephalitis viruses. we cloned and sequenced the complete nonstructural gene-coding region of langat virus (strain tp21) and compared the deduced amino acid sequences of each nonstructural protein to those of other flaviviruses. by alignment with the reported amino acid sequences of the nonstructural proteins of several flaviviruses, we were able to predict proteolytic cleavage sites ...19921316684
new approaches to flavivirus vaccine development. 19921318137
combined simian hemorrhagic fever and ebola virus infection in cynomolgus monkeys.simian hemorrhagic fever (shf) virus and a new strain of ebola virus were isolated concurrently in recently imported cynomolgus monkeys (macaca fascicularis) being maintained in a quarantine facility. ebola virus had never been isolated in the u.s. previously and was presumed to be highly pathogenic for humans. a chronology of events including measures taken to address the public health concerns is presented. the clinicopathologic features of the disease were abrupt anorexia, splenomegaly, marke ...19921318446
inactivation of viruses related to hepatitis c virus by pasteurization in human plasma derivatives. 19921319182
a stochastic analysis of three viral sequences.this paper analyzes the nucleotide sequences of three viruses: kunjin, west nile, and yellow fever. each virus has one long open reading frame of greater than 10,200 nucleotides that codes for four structural and seven nonstructural genes. the kunjin and west nile viruses are the most closely related pair, when assessed on the basis of matches between their nucleotide sequences. as would be expected, the matching is least for bases at third-position codon sites and is greatest for second-positio ...19921321321
[transfusion-associated non-a, non-b, non-c hepatitis caused by flaviviruses].hepatitis c virus was shown to be a member of the flavivirus family. tick-borne encephalitis virus and west nile virus, members of the same family occur in hungary, too. serum samples from patients suffering from transfusion associated hepatitis were tested with yellow fever virus antigens for specific igg, and igm using immunofluorescence test. eight hundred serum samples were tested. yellow fever virus related igg antibodies were found in 232 sera. in the case of 72 patients specific igm antib ...19921321397
comparison of haemagglutination inhibition and indirect fluorescent antibody tests to detect certain flavivirus antibodies in equines.formalinized goose erythrocytes were used in haemagglutination inhibition (hi) and indirect fluorescent-antibody (ifa) tests to detect antibodies to japanese encephalitis (je) and west nile (wn) viruses in equines. paired serum samples from 31 cases having clinical symptoms of flaviviral infections (je and wn viruses) and 45 controls were examined. for hi test, formalinized goose erythrocytes were used as such, whereas in ifa test, formalinized goose erythrocytes were first coated with respectiv ...19921321546
isolation of kunjin virus from a patient with a naturally acquired infection.to describe the first isolation of kunjin virus from a patient with a natural infection.19921321945
a new genotype of japanese encephalitis virus from indonesia.primer-extension sequencing of the rna template of polio, dengue, rift valley fever, and japanese encephalitis (je) viruses has provided new information on their geographic distribution, origin, and evolution. in a previous study of 46 diverse je virus strains, we demonstrated the existence of three distinct je genotypes in asia. we now report the occurrence of a fourth genotype. in the present study, 19 je virus isolates, representing various geographic regions of asia and a 50-year time span, ...19921322071
the complete nucleotide sequence of cell fusing agent (cfa): homology between the nonstructural proteins encoded by cfa and the nonstructural proteins encoded by arthropod-borne flaviviruses.cell fusing agent (cfa) is an rna virus originally isolated from a line of aedes aegypti mosquito cells. although our characterization of the virus many years ago showed that it resembled the flaviviruses, there was no detectable serological cross-reaction with members of the genus flavivirus. furthermore, unlike the well-studied members of the genus flavivirus, cfa did not replicate in any of several vertebrate cell lines tested. we have now determined the nucleotide sequence of the cfa genome. ...19921322586
molecular and ultrastructural analysis of heavy membrane fractions associated with the replication of kunjin virus rna.in subcellular extracts of kunjin virus-infected cells prepared by lysis and differential centrifugation, the viral rna polymerase, rna and proteins were associated mainly with cytoplasm. when the cytoplasmic extract (500 g supernate) of infected cells labelled for 3 h from 24 h post-infection was further fractionated by rapid centrifugation through a sucrose density gradient, all viral products were located only in dense or "heavy membrane" fractions, which contained three types of virus-induce ...19921322651
heterologous resistance to superinfection by louping ill virus persistently infected cell cultures.louping ill virus, a tick-borne arbovirus readily established a persistent infection in porcine kidney (ps) cells after initially inducing minor cytopathic changes. nucleotide sequence analysis of the envelope glycoprotein of the viral rna recovered from the persistently infected cells showed no changes as compared with the virus used to establish persistent infections. more than 80 per cent of the cells contained virus specific antigen when analysed by indirect immunofluorescence microscopy. th ...19921322654
neuronal cell cultures as a model for assessing neurotoxicity induced by encephalitic viruses.primary dispersed and organotypic cultures were prepared from selected brain areas and spinal cords of rat (sprague-dawley) and mouse (sjl/ola(f) ness-ziona) fetuses and neonates. following fiber regeneration, synapse formation and myelination, cultures were infected with one of the following viruses: rabies cvs-21 strain, sindbis alphavirus, west-nile flavivirus and theiler murine encephalomyelitis virus. light and electron microscopical studies showed clear differences in the target cells for ...19921324447
molecular genetics of pestiviruses.recent developments in understanding the molecular genetics of pestiviruses are reviewed. the genomic rna of several pestiviruses has been molecularly cloned and sequenced. the genetic organization of the viral protein coding region has been refined, and the complete complement of virus-encoded proteins has been elucidated. viral gene expression involves both co-translational and post-translational precursor polyprotein processing. biogenesis of the virion structural proteins requires the proteo ...19921325329
nucleotide sequence of the envelope glycoprotein of negishi virus shows very close homology to louping ill virus.negishi virus, a member of the family flaviviridae, was originally isolated in japan, during an outbreak of japanese encephalitis. antigenically, however, negishi virus resembles the tick-borne rather than the mosquito-borne flaviviruses. monoclonal antibodies that bind louping ill virus showed a close antigenic relationship between louping ill and negishi virus. the genes encoding the envelope glycoprotein of negishi virus (strain 3248/49/p10) and louping ill virus (strain sb526) were cloned an ...19921326816
proteolytic processing of a murray valley encephalitis virus non-structural polyprotein segment containing the viral proteinase: accumulation of a ns3-4a precursor which requires mature ns3 for efficient processing.the proteolytic processing of a non-structural polyprotein segment from the cytoplasmic domain of ns2a to the c terminus of ns5 of murray valley encephalitis (mve) virus was examined, when expressed from cdna via a vaccinia virus recombinant, in transiently transfected cos cells, or synthesized by cell-free translation. cleavages mediated by the virus-encoded proteinase domain in ns3 at the junctions of ns2a-2b, ns2b-3 and ns4b-5 were catalysed efficiently. however, the cleavage at the ns3-4a ju ...19921328486
restimulated memory tc cells have a higher apparent avidity of interaction with targets than primary virus-immune tc cells as indicated by anti-cd8 blocking.previous experiments have shown that whereas a secondary in vitro kunjin-immune cytotoxic t (tc) cell population lysed equally well targets infected with either native flavivirus or a recombinant vaccinia virus expressing the immunodominant determinant, primary in vivo kunjin-immune tc cells were able to lyse only the recombinant vaccinia virus-infected targets. using cd8 blockade to assess the avidity of t cell-target interaction, recombinant-infected targets express antigen more efficiently th ...19921330899
detection of flavivirus antigens in purified infected vero cell plasma membranes.the types of kunjin virus-specified proteins present in purified vero cell plasma membrane were studied. immunofluorescence of unfixed kunjin virus-infected whole cell monolayers, indicated that two structural proteins (envelope and prm) and three non-structural proteins (ns1, 3 and 5) were found at the plasma membrane. there was no obvious progressive accumulation of the observed antigens over the time periods between 8 to 24 h p.i. thus sds-page analysis was performed using purified radiolabel ...19921331144
dispersal of adult females of culex annulirostris in griffith, new south wales, australia.the dispersal of culex annulirostris, a major arbovirus vector in australia, was studied in griffith, n.s.w. using a mark-release-recapture technique. from an empirical model of dispersal, fitted to data on recaptured adults, the average distance dispersed was 6.8 km (95% c.l. 4.1-40.9 km), and 50% of the population dispersed 4.8 km or more. maximum recorded dispersal was 8.7 km, and 2 individuals traveled more than 5 km in 1 day. the relevance of the findings to control strategy is discussed.19921331320
[genomic structure of togavirus and flavivirus]. 19921332117
[replication and gene expression of flavivirus]. 19921332124
[processing of flavivirus proteins]. 19921332128
arboviruses as aetiological agents of encephalitis in the people's republic of china.a serological study was undertaken to determine the role of arboviruses as etiological agents of encephalitis in the people's republic of china (prc). paired sera were collected during mosquito seasons in 1988-1990 from 614 patients with possible viral encephalitis in 15 regions of prc and tested for haemagglutination inhibiting antibodies to selected arboviruses. seroconversions were documented to alphavirus and flavivirus antigens in 13.0 and 18.7% of patients respectively in most of the study ...19921332220
comparative molecular biology of flaviviruses and hepatitis c virus.currently available sequence information suggests that the genome organization of hepatitis c virus is similar to that of flaviviruses. a positive-stranded genomic rna contains a single long open reading frame (orf) which is flanked by 5' and 3' noncoding sequences. this rna codes for structural proteins at the 5' end (starting with the capsid protein) and a set of nonstructural proteins in the remainder of the genome. the latter provide essential virus-specific functions for the viral life cycl ...19921333320
proteins encoded in the 5' region of the pestivirus genome--considerations concerning taxonomy.the first protein encoded within the pestivirus open reading frame is a nonstructural protein which removes itself from the polyprotein by autoproteolytic cleavage. the following nucleocapsid protein ends just before a putative signal sequence preceding three glycosylated proteins. all three glycoproteins are part of the viral envelope and exist in the form of disulfide-linked dimers. pestiviruses have recently been reclassified as members of the family flaviviridae which now comprises three gen ...19921336240
envelope protein sequences of dengue virus isolates th-36 and th-sman, and identification of a type-specific genetic marker for dengue and tick-borne flaviviruses.complementary dnas were synthesized from the envelope protein genes of two isolates of dengue virus (th-36 and th-sman, previously suggested as possible dengue virus type 5 and dengue virus type 6 respectively) and amplified by the polymerase chain reaction using sense and antisense primers designed from conserved dengue virus gene sequences. the amplified cdna clones were sequenced in both directions by double-stranded dideoxynucleotide sequencing. alignment with published dengue virus sequence ...19921339466
[laboratory diagnosis and symptoms of dengue, during an outbreak in the ribeirão preto region, sp, brazil].a dengue type 1 outbreak started in the ribeirao preto region, north of sao paulo state, brazil, in november of 1990. about 3500 dengue cases were confirmed by blood tests until february of 1991. the virus research unit of the faculty of medicine of ribeirao preto-sao paulo state university, studied 502 dengue suspect cases. the serologic diagnosis of dengue type 1 was confirmed by haemagglutination inhibition test (hai) in 19% of the cases. diagnosis was done later by using an enzyme immuno ass ...19921340025
analysis of murine major histocompatibility complex class ii-restricted t-cell responses to the flavivirus kunjin by using vaccinia virus expression.the present paper analyzes the influence of major histocompatibility complex (mhc) class ii (ir) genes on mhc class ii-restricted t-cell responses to west nile virus (wnv) and recombinant vaccinia virus-derived kunjin virus antigens and identifies the immunodominant kunjin virus antigens. generally, mice were primed by intravenous infection with wnv or kunjin virus, and their cd4+ t cells were stimulated in vitro 14 days later with wnv or kunjin virus antigens to pulse macrophage or b-cell antig ...19921349926
arbovirus isolations from mosquitoes collected during 1988 in the senegal river basin.during august and september 1988, we collected adult mosquitoes from 14 locations in the senegal river basin to search for evidence of rift valley fever (rvf) viral activity one year after the 1987 outbreak, which occurred along the senegal-mauritania border. more than 62,000 specimens representing 18 species in seven genera were collected with carbon dioxide-baited, solid-state army miniature light traps and sheep-baited traps. twenty virus isolations from culex, aedes, and anopheles mosquitoes ...19921361722
selective inhibition of arthropod-borne and arenaviruses in vitro by 3'-fluoro-3'-deoxyadenosine.a novel nucleoside analog, 3'-fluoro-3'-deoxyadenosine (3'f3'dado), was evaluated for antiviral activity against several arthropod-borne and arenaviruses in vero cell culture. the following 50% inhibitory concentrations (ec50) of virus plaque formation were obtained against the test viruses: semliki forest (10.3 microm) and venezuelan equine encephalitis (5.3 microm) alphaviruses, lymphocytic choriomeningitis (7.7 microm) and pichinde (greater than 32 microm) arenaviruses, punta toro (greater th ...19921365816
use of recombinant fusion proteins and monoclonal antibodies to define linear and discontinuous antigenic sites on the dengue virus envelope glycoprotein.sixteen overlapping fragments of the dengue-2 virus envelope (e) protein, expressed as trpe-e fusion products in escherichia coli, were used to map the epitopes defined by a panel of 20 monoclonal antibodies (mabs) by immunoblotting. using this technique, the amino acid sequence of six antigenic domains on the e protein was characterized. nonneutralizing mabs were found to define either linear-specific, subcomplex-specific (amino acids 22-58), and complex-specific (amino acids 304-332) epitopes ...19921372140
enhancement of the antibody response to flavivirus b-cell epitopes by using homologous or heterologous t-cell epitopes.we have been investigating the t-helper (th)-cell response to the flavivirus envelope (e) glycoprotein. in our studies with murray valley encephalitis (mve) virus, we previously identified synthetic peptides capable of priming th lymphocytes for an in vitro antivirus proliferative response (j. h. mathews, j. e. allan, j. t. roehrig, j. r. brubaker, and a. r. hunt, j. virol. 65:5141-5148, 1991). we have now characterized in vivo th-cell priming activity of one of these peptides (mve 17, amino aci ...19921374807
broad cross-reactivity with marked fine specificity in the cytotoxic t cell response to flaviviruses.cytotoxic t (tc) cells were generated in mice of five h-2 haplotypes against the flaviviruses kunjin and west nile (wnv). a panel of recombinant vaccinia viruses which between them expressed cdna of the entire kunjin virus genome were used to infect targets. anti-kunjin virus responses to determinants derived from non-structural proteins, especially ns3, ns4a and ns4b, were dominant in most mouse strains; usually only one class i major histocompatibility complex (mhc) restriction element was inv ...19921375278
analysis of tick-borne encephalitis virus antigens by monoclonal antibodies.monoclonal antibodies (mabs) against central european tick-borne encephalitic virus, strain hypr, were used for determination and characterization of viral antigens of infected ps cells. the mabs reacted in immunoblotting with flavivirus glycoprotein e (56 kd), and nonstructural protein ns3 (70 kd). according to enzyme immunoassay with infected cells, ns3 antigen is expressed in the plasmalemma.19921375704
induction of cytotoxic t cells to a cross-reactive epitope in the hepatitis c virus nonstructural rna polymerase-like protein.cytotoxic t lymphocytes (ctl) have been found to mediate protection in vivo against certain virus infections. ctl also may play an important role in control of infection by hepatitis c virus (hcv), but no ctl epitopes have yet been defined in any hcv protein. the nonstructural protein with homology to rna polymerase should be a relatively conserved target protein for ctl. to investigate the epitope specificity of ctl specific for this protein, we used 28 peptides from this sequence to study muri ...19921376366
direct sequencing of large flavivirus pcr products for analysis of genome variation and molecular epidemiological investigations.the polymerase chain reaction (pcr) was used to amplify viral cdnas from selected regions of dengue genomic rna by using appropriate 'consensus' primers. dna amplicons containing the structural genes from all 4 dengue serotypes were prepared and directly sequenced using dengue-virus-specific primers. this method can characterize reliably flavivirus field isolates at the molecular level without extensive virus propagation and molecular cloning, and will be a valuable tool for molecular epidemiolo ...19921379606
a synthetic peptide to the e glycoprotein of murray valley encephalitis virus defines multiple virus-reactive t- and b-cell epitopes.synthetic peptides from the envelope glycoprotein sequence of murray valley encephalitis (mve) virus were previously evaluated in various strains of mice for both the induction of antibody and the in vitro proliferation of peptide-primed t-helper (th) cells. mve peptide 6 (amino acids 230 to 251) elicited reciprocal th- and b-cell reactivity with native mve virus after primary inoculation of c57bl/6 mice. in this study, we prepared overlapping subunit peptides of mve peptide 6 and evaluated thei ...19921383567
a simple and rapid method of preparing large fragments of dengue virus cdna from replicative-form rna using reverse transcriptase and pcr.a method is described for cloning large fragments (1.5 kb to 2 kb) of dengue virus cdna from replicative-form viral rna. aedes albopictus cells (c6/36 clone) infected with dengue virus contain double-stranded, replicative-form rna molecules which were used as a template for an initial reverse transcription using a primer containing sequence homologous to regions of the genome at or near the 3' end of the gene being studied. the product was then used as a template for polymerase chain reaction (p ...19921385464
[the protective activity of preparations made from the tick-borne encephalitis virus grown using different cell cultures].the preparations of tick-borne encephalitis (tbe) virus grown in swine embryo kidney cell culture have been shown to possess pronounced protective activity per unit of virion protein e in comparison with tbe virus preparations derived from cell culture 4647 and chick embryo cell culture. the antigenic activity of all virus preparations under study has proved to be practically the same. the role of post-translation modifications of tbe virus protein e in the manifestation of some of its biologica ...19921414102
purification of native dengue-2 viral proteins and the ability of purified proteins to protect mice.both the envelope structural protein and the non-structural ns1 protein have been purified from the flavivirus dengue-2 by high-pressure liquid chromatography. these purified proteins maintain their reactivity with monoclonal antibodies. when tested in mice, the envelope protein elicited neutralizing antibodies and partially protected the animals against a lethal viral challenge. the mice responded to the non-structural protein by producing antibodies; however, these antibodies were not neutrali ...19921443338
flavivirus induces mhc antigen on human myoblasts: a model of autoimmune myositis?infection of human embryonic myoblasts by west nile virus (wnv), a flavivirus, caused significant upregulation of class i and ii mhc expression as determined by flow cytometry. after 48 hours at a multiplicity of infection of 5 pfu/cell, a sixfold increase in mhc class i expression was induced from initially low levels of expression. in contrast, mhc class ii was induced de novo to five times the control fluorescence level. at least 70% of the cells were infected as determined using fluorescence ...19921488065
infectious japanese encephalitis virus rna can be synthesized from in vitro-ligated cdna templates.japanese encephalitis virus (jev) is a positive-stranded enveloped rna virus that belongs to the family flaviviridae. genomic jev rna is approximately 11 kb long and encodes 10 proteins, 3 structural and 7 nonstructural. a full-length cdna copy of the jev genome was constructed by in vitro ligation of two cdna fragments which encode the 5' (nucleotide positions 1 to 5576) and 3' (nucleotide positions 5577 to 10976) halves of the genome. t7 rna polymerase transcripts of the ligated full-length cd ...19921501281
[expression of the gene for tick-borne viral encephalitis virus ns3 protein in escherichia coli cells].on the base of two overlapping cdna-clones of tick-borne encephalitis virus (tbev) genome and synthetic dna fragments full dna-copy of the tbev ns3 protein gene was constructed and expressed in the e. coli cells. it was demonstrated that the relatively low biosynthesis level of full-length ns3 protein in the bacteria was due to the toxicity of the n-terminal region of the protein, consisting of it's first 180 amino acid residues. a form of the gene with deletion of nucleotides coding for the tox ...19921508165
cleavage of the dengue virus polyprotein at the ns3/ns4a and ns4b/ns5 junctions is mediated by viral protease ns2b-ns3, whereas ns4a/ns4b may be processed by a cellular protease.the cleavage mechanism utilized for processing of the ns3-ns4a-ns4b-ns5 domain of the dengue virus polyprotein was studied by using the vaccinia virus expression system. recombinant vaccinia viruses vns2b-ns3-ns4a-ns4b-ns5, vns3-ns4a-ns4b-ns5, vns4a-ns4b-ns5, and vns4b-ns5 were constructed. these recombinants were used to infect cells, and the labeled lysates were analyzed by immunoprecipitation. recombinant vns2b-ns3-ns4a-ns4b-ns5 expressed the authentic ns3 and ns5 proteins, but the other reco ...19921531368
a short form of the tick-borne encephalitis virus ns3 protein.using monoclonal antibodies to the tick-borne encephalitis virus (tbe) nonstructural protein ns3 two forms of this protein were revealed in tbe-infected mammalian cells: a full-length form (69 kda) and a short form (49 kda) which has not been observed before and was called ns3'. recombinant plasmids were constructed and various fragments of the tbe ns3 gene were expressed in rabbit reticulocyte lysate. by analyzing immune precipitates of 35s-labeled translation products, we could monitor and loc ...19921551439
dengue virus infection of human skin fibroblasts in vitro production of ifn-beta, il-6 and gm-csf.dengue virus is transmitted to humans by the bite of infected mosquitos. in our efforts to understand the pathogenesis of dengue virus infection, we examined whether skin fibroblasts can be infected in vitro with dengue viruses. fibroblasts could be infected with dengue viruses, yellow fever virus and west nile virus. dengue virus antigen-positive cells were detected as early as 4 h and the percentage of dengue virus antigen-positive cells reached maximum levels by 24 h after infection. high tit ...19921571018
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