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translation elongation factor-1 alpha interacts with the 3' stem-loop region of west nile virus genomic rna.the conserved 3'-terminal stem-loop (3' sl) of the west nile virus (wnv) genomic rna was previously used to probe for cellular proteins that may be involved in flavivirus replication and three cellular proteins were detected that specifically interact with the wnv 3' sl rna (j. l. blackwell and m. a. brinton, j. virol. 69:5650-5658, 1995). in this study, one of these cellular proteins was purified to apparent homogeneity by ammonium sulfate precipitation and liquid chromatography. amino acid seq ...19979261361
ultrastructure of kunjin virus-infected cells: colocalization of ns1 and ns3 with double-stranded rna, and of ns2b with ns3, in virus-induced membrane structures.the subcellular location of the nonstructural proteins ns1, ns2b, and ns3 in vero cells infected with the flavivirus kunjin was investigated using indirect immunofluorescence and cryoimmunoelectron microscopy with monospecific antibodies. comparisons were also made by dual immunolabelling using antibodies to double-stranded rna (dsrna), the putative template in the flavivirus replication complex. at 8 h postinfection, the immunofluorescent patterns showed ns1, ns2b, ns3, and dsrna located in a p ...19979261387
superinfection exclusion of alphaviruses in three mosquito cell lines persistently infected with sindbis virus.three aedes albopictus (mosquito) cell lines persistently infected with sindbis virus excluded the replication of both homologous (various strains of sindbis) and heterologous (aura, semliki forest, and ross river) alphaviruses. in contrast, an unrelated flavivirus, yellow fever virus, replicated equally well in uninfected and persistently infected cells of each line. sindbis virus and semliki forest virus are among the most distantly related alphaviruses, and our results thus indicate that mosq ...19979261447
schizophrenia, rheumatoid arthritis and natural resistance genes.the strong negative correlation between schizophrenia and rheumatoid arthritis might provide clues as to the aetiology of these two diseases. an immunological explanation has been sought in the hla sector of the major histocompatibility complex, which has been shown to have a role in the development of rheumatoid arthritis. the search for an association between schizophrenia and hla haplotypes, however, has yielded only controversial results. nevertheless, an autoimmune aetiology is still suspec ...19979264173
expression of the dengue virus structural proteins in pichia pastoris leads to the generation of virus-like particles.we have expressed cdna encoding the dengue virus structural proteins in pichia pastoris by chromosomal integration of an expression cassette containing the dengue virus structural genes (cprme). the yeast recombinant e protein migrated during sds-page as a 65 kda protein when analysed by western blotting and radioimmunoprecipitation, which is the expected molecular mass for correctly processed and glycosylated e protein. treatment with endoglycosidases showed that the recombinant e protein was m ...19979266980
expression of immunoglobulin superfamily cell adhesion molecules on murine embryonic stem cells.the expression of cell adhesion molecules of the ig superfamily (ig-cam) were examined on embryonic stem (es) cells during culture in vitro. es cells maintained an undifferentiated phenotype when cultured in the presence of leukemia inhibitory factor (lif) or with fibroblast feeder cells; > 90% of cells reacted positively to an antibody (ecma-7) that marks undifferentiated es cells. using flow cytometry, high concentrations of icam-1, vcam-1, and ncam antigens were detected on undifferentiated e ...19979282991
gb virus c/hepatitis g virus and other putative hepatitis non a-e viruses.the identification of the major agents causing human hepatitis (hepatitis a, b, c, d and e viruses) was achieved during the last 30 years. these viruses are responsible for the vast majority of human viral hepatitis cases, but there are still some cases epidemiologically related to infectious agents without any evidence of infection with known virus, designated as hepatitis non a-e. those cases are considered to be associated with at least three different viruses: 1--hepatitis b virus mutants ex ...19969293092
novel hepatitis c virus protease inhibitors: thiazolidine derivatives.this study evaluated the inhibitory effects of thiazolidine derivatives on hepatitis c virus (hcv) protease and other human serine proteases. the inhibition efficacy was tested with a reversed-phase high-performance liquid chromatography (hplc) assay system using a ns3-ns4a fusion protein as the hcv protease and a synthetic peptide substrate that mimics the ns5a-5b junction. nine thiazolidine derivatives showed more than 50% inhibition at 50 microg/ml. the most potent derivative was rd4-6250, wi ...19979299567
[secretion of tick-borne encephalitis virus glycoproteins e and ns1 heterocomplex in the late stage of infection].the heterocomplex of glycoproteins e and ns1 of tick-borne encephalitis (tbe) virus was isolated from culture fluid of continuous spev (porcine embryo kidney) cells by affinity chromatography on cl4b sepharose with immobilized monoclonal antibodies to tbe virus protein ns1. comparison of the tbe e-ns1 heterocomplex from culture fluid and cells showed the predominance of secreted extracellular form. a similar tbe virus heterocomplex e-ns1 was revealed in the blood sera of patients with tbe but no ...19979304300
current status of hepatitis g virus (gbv-c) in transfusion: is it relevant?a new flavivirus, provisionally designated hepatitis g virus or gbv-c has recently been described. the virus is parenterally transmitted by exposure to blood through transfusion, intravenous drug use and haemodialysis. heat- or chemically-treated blood products are associated with reduced risk of infection. the virus may also be transmitted from mother to infant and by the sexual route. although hepatitis g virus has been detected in patients with acute and chronic hepatitis, a causative role of ...19979304773
availability of a second upstream aug can completely overcome inhibition of protein synthesis initiation engendered by mrna secondary structure encompassing the start codon.secondary structure analysis of the mrna from a nonproductive construct carrying the nonstructural gene 3 (ns3) of japanese encephalitis virus revealed the presence of a potential 28 nucleotide long stem and loop beginning with the guanine of the initiation codon aug that had a calculated stabilization energy of -13 kcal/mol (delta gfzero). provision of an additional aug along with three codons upstream resulted in complete relief of inhibition. n-terminal amino acid sequence of the recombinant ...19979322762
the sensitive detection and quantitation of antibody to hcv by using a microsphere-based immunoassay and flow cytometry.antibody to hcv core and ns3 was quantified by using a microsphere immunoassay and flow cytometry. antibody to core and ns3 was elevated in the 85 seropositive blood donors tested. the amount of either antibody varied over two logs although greater variation was seen with the antibody to ns3 than was seen with antibody to core. in three documented acute hcv cases, the microsphere assay detected antibody prior to antibody detection using the reference methods. twenty donor samples were indetermin ...19979332816
proteolytic activation of tick-borne encephalitis virus by furin.flaviviruses are assembled intracellularly in an immature form containing heterodimers of two envelope proteins, e and prm. shortly before the virion exits the cell, prm is cleaved by a cellular enzyme, and this processing step can be blocked by treatment with agents that raise the ph of exocytic compartments. we carried out in vivo and in vitro studies with tick-borne encephalitis (tbe) virus to investigate the possible role of furin in this process as well as the functional consequences of prm ...19979343204
molecular virology of hepatitis c virus. 19979349458
hepatitis g virus infection in hemodialysis patients and the effects of interferon treatment.to characterize the nature of hepatitis g virus (hgv) infections in hemodialysis patients and to determine the responsiveness of hgv to antiviral therapy in these patients.19979362177
serum hepatitis g virus rna in patients with chronic viral hepatitis.the hepatitis g virus (hgv) is a newly described flavivirus that affects a high proportion of patients with chronic viral hepatitis: our objective was to determine what role hgv might play in the course of disease.19979362178
frequencies of gb virus c/hepatitis g virus genomes and of specific antibodies in german risk and non-risk populations.the prevalence of the new flavivirus gb virus c/hepatitis virus g (gbv-c/hgv) in different german populations was investigated by detection of viral genomes and anti-e2 antibodies. while blood donors had an overall prevalence of 10.4% there were increased rates for hemophiliacs (54.7%), hemodialysis patients (30.2%), male homosexuals (30.2%) and intravenous drug users (74.4). most gbv-c/hgv positive samples were either viral genome positive or antibody positive, exclusively. samples with the rar ...19979365885
the molecular basis of virulence of the encephalitogenic flaviviruses. 19979367356
analysis of a recombinant dengue-2 virus-dengue-3 virus hybrid envelope protein expressed in a secretory baculovirus system.in a step towards a tetravalent dengue virus subunit vaccine which is economical to produce, highly immunogenic and stable, a hybrid dengue virus envelope (e) protein molecule has been constructed. it consists of 36 amino acids from the membrane protein, the n-terminal 288 amino acids of the dengue-2 virus e protein plus amino acids 289-424 of the dengue-3 virus e protein. it has been engineered for secretory expression by fusion to a mellitin secretory signal sequence and truncation of the hydr ...19979367357
early e-selectin, vcam-1, icam-1, and late major histocompatibility complex antigen induction on human endothelial cells by flavivirus and comodulation of adhesion molecule expression by immune cytokines.expression of e-selectin (elam-1, cd62e) on human umbilical vein endothelial cells significantly increased 30 min postinfection with the flavivirus west nile virus (wnv), was maximal by 2 h postinfection, and declined to baseline levels within 24 h. expression of icam-1 (cd54) and vcam-1 (cd106) was significantly increased by 2 h and maximal at 4 h after infection. p-selectin (cd62p) expression was unaffected by wnv. upregulation occurred earlier than that caused by tumor necrosis factor alpha ( ...19979371591
naked dna vaccines expressing the prm and e genes of russian spring summer encephalitis virus and central european encephalitis virus protect mice from homologous and heterologous challenge.naked dna vaccines expressing the prm and e genes of two tick-borne flaviviruses, russian spring summer encephalitis (rsse) virus and central european encephalitis (cee) virus were evaluated in mice. the vaccines were administered by particle bombardment of dna-coated gold beads by accell gene gun inoculation. two immunizations of 0.5 to 1 microg of rsse or cee constructs/dose, delivered at 4-week intervals, elicited cross-reactive antibodies detectable by enzyme-linked immunosorbent assay and h ...19979371620
trans-complementation of yellow fever virus ns1 reveals a role in early rna replication.mutational analysis of the nonstructural protein 1 (ns1) of yellow fever virus (yf) has implicated it in viral rna replication. to further explore this observation, we sought a method for uncoupling ns1 function from ns1 expression and processing as part of the large yf polyprotein. here we describe a strategy for providing ns1 in trans, utilizing a noncytopathic sindbis virus vector. replication of a defective yf genome containing a large in-frame deletion of ns1 was dependent on functional exp ...19979371625
capillary electrophoresis for purity estimation and in-process testing of recombinant gb virus-c proteins.protein purity estimation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) coupled with scanning densitometry is a critical component in the manufacture of recombinant proteins for commercial diagnostic assays. however, the procedure is time consuming and often difficult to reproduce because commercial dyes that are used for visualizing proteins do not bind in a stoichiometric fashion for all proteins. the present report describes the use of a rapid and dye-independent sds ...19979384714
cotranslational membrane insertion of the serine proteinase precursor ns2b-ns3(pro) of dengue virus type 2 is required for efficient in vitro processing and is mediated through the hydrophobic regions of ns2b.polyprotein processing of dengue virus type 2, a positive strand rna virus, is carried out by the host signal peptidase and a novel two-component viral proteinase of the serine proteinase family, ns2b/ns3(pro), in the endoplasmic reticulum. using an in vitro processing system, we examined the cis and trans cleavages of the 2b/3 and 4b/5 sites by ns2b/ns3(pro), respectively. lysates of bhk-21 cells coexpressing ns2b and ns3(pro) mediated trans cleavage of the 4b/5 site in vitro, and the protease ...19979388208
detection of tick-borne encephalitis virus by sample transfer, plaque assay and strand-specific reverse transcriptase polymerase chain reaction: what do we detect?experimental inoculation of mice provides a well characterized model for studying infection with tick-borne encephalitis virus (tbev), a flavivirus pathogenic for humans. conflicting data on the kinetics of viremia and the development of virus titers in the brain, however, were only recently shown to have resulted from the use of assay systems with different levels of sensitivity in the titration of tbev, i.e. plaque assay or sample transfer into naive recipient mice. theoretically, rt-pcr could ...19979395135
hepatitis g virus infection before and after liver transplantation. liver transplantation database.the hepatitis g virus is a newly discovered flavivirus that has been linked to acute and chronic hepatitis of unknown cause. we determined the prevalence of hepatitis g virus infection in 179 selected patients undergoing liver transplantation at three centers participating in the national institute of diabetes and digestive and kidney diseases (niddk) liver transplantation database. pretransplantation and posttransplantation specimens were tested for hepatitis g virus rna by polymerase chain rea ...19979404956
antibodies protect mice against challenge with tick-borne encephalitis virus (tbev)-infected macrophages.tbev is a flavivirus highly pathogenic for humans. by transfer of antibodies directed to the tbev surface glycoprotein e into mice, immune protection against subsequent inoculation with free tbev particles could be achieved. after natural tbev infection via the skin, however, cells of the monocyte/macrophage lineage were recently demonstrated to represent an important source of local virus replication before viraemia occurs. whether antibodies can protect against virus challenge when contracted ...19979409636
[hepatitis gbv isolated in acute liver failure. successful outcome after liver transplantation].fulminant hepatic failure is a life-threatening condition associated with a mortality of approximately 80 per cent. liver transplantation may be the only life-saving recourse in such cases. the condition can be caused by any of a number of different agencies such as viral infection, or toxic, circulatory or metabolic factors, though in a large proportion of cases the aetiology is unknown. recently, knowledge has accumulated of a new hepatitis virus, hepatitis gb virus (hgbv), a flavivirus remote ...19979411092
amgen hangs hopes on hepatitis c. 19979415879
phylogeny of the genus flavivirus.we undertook a comprehensive phylogenetic study to establish the genetic relationship among the viruses of the genus flavivirus and to compare the classification based on molecular phylogeny with the existing serologic method. by using a combination of quantitative definitions (bootstrap support level and the pairwise nucleotide sequence identity), the viruses could be classified into clusters, clades, and species. our phylogenetic study revealed for the first time that from the putative ancesto ...19989420202
dna immunization with japanese encephalitis virus nonstructural protein ns1 elicits protective immunity in mice.japanese encephalitis virus (jev), a mosquito-borne flavivirus, is a zoonotic pathogen that is prevalent in some southeast asian countries and causes acute encephalitis in humans. to evaluate the potential application of gene immunization to jev infection, we characterized the immune responses from mice intramuscularly injected with plasmid dna encoding jev glycoproteins, including the precursor membrane (prm) plus envelope (e) proteins and the nonstructural protein ns1. when injected with the p ...19989420215
mutagenesis of the ns3 protease of dengue virus type 2.the flavivirus protease is composed of two viral proteins, ns2b and ns3. the amino-terminal portion of ns3 contains sequence and structural motifs characteristic of bacterial and cellular trypsin-like proteases. we have undertaken a mutational analysis of the region of ns3 which contains the catalytic serine, five putative substrate binding residues, and several residues that are highly conserved among flavivirus proteases and among all serine proteases. in all, 46 single-amino-acid substitution ...19989420267
first record in america of aedes albopictus naturally infected with dengue virus during the 1995 outbreak at reynosa, mexico.mosquito collections were conducted during a dengue outbreak in reynosa, tamaulipas, mexico, july-december 1995. a total of 6694 adult mosquitoes (four genera and nine species) were captured, of which 2986 (78.3% females and 21.7% males) were aedes albopictus and 2339 (39.7% females and 60.3% males) were ae.aegypti. these two species comprised 84.2% of the total collection. specimens were grouped into pools, nearly 50% of them processed for detection of virus by cythopathic effect in c6-36 and v ...19979430106
vertical transmission of dengue.dengue, an important mosquito-borne flavivirus infection, is endemic in southeast asia. we describe two mothers who had acute dengue 4 and 8 days before the births of their infants. one mother had worsening of her proteinuric pregnancy-induced hypertension, liver dysfunction, and coagulopathy and required multiple transfusions of whole blood, platelets, and fresh frozen plasma. her male infant was ill at birth, developed respiratory distress and a large uncontrollable left intracerebral hemorrha ...19979431381
evaluation of a rapid immunochromatographic test for diagnosis of dengue virus infection.a rapid (<7-min) immunochromatographic test for immunoglobulin m (igm) and igg antibodies to dengue viruses was evaluated by using hospital admission and discharge sera from 124 patients. the reference laboratory diagnosis was based on the results of virus isolation, hemagglutination-inhibition assay (hai), and enzyme immunoassay (eia). by the standard assays, patients experienced primary dengue virus infection (n = 30), secondary dengue virus infection (n = 48), japanese encephalitis (je) virus ...19989431954
characterisation of an hcv ns3/ns4a proteinase fusion protein expressed in e.coli using synthetic peptide substrates. 19979450052
conversion of dengue virus replicative form rna (rf) to replicative intermediate (ri) by nonstructural proteins ns-5 and ns-3.dengue viruses infect more than 100 million people each year and cause serious clinical manifestations. it is important to understand the replication of these viruses so that therapeutic and/or prophylactic agents may be designed. dengue virus type 2 nonstructural proteins ns-5 and ns-3 were produced by in vitro transcription and translation of cloned genes. both proteins possessed rna-dependent rna polymerase activity as measured by their ability to convert purified replicative form (rf) rna to ...19989452298
dengue fever epidemic potential as projected by general circulation models of global climate change.climate factors influence the transmission of dengue fever, the world's most widespread vector-borne virus. we examined the potential added risk posed by global climate change on dengue transmission using computer-based simulation analysis to link temperature output from three climate general circulation models (gcms) to a dengue vectorial capacity equation. our outcome measure, epidemic potential, is the reciprocal of the critical mosquito density threshold of the vectorial capacity equation. a ...19989452414
definition of an epitope on ns3 recognized by human cd4+ cytotoxic t lymphocyte clones cross-reactive for dengue virus types 2, 3, and 4.the role of dengue virus-specific serotype-cross-reactive t lymphocytes in recovery from and pathogenesis of dengue virus infections is not known. in the present paper, we have defined a dengue serotype-cross-reactive epitope recognized by two cd4+ cd8- cytotoxic t lymphocyte (ctl) clones, jk36 and jk46. these t cell clones were established from the peripheral blood t lymphocytes of a dengue-3-immune donor, using a limiting dilution method. jk36 and jk46 were cross-reactive for dengue virus type ...19989454689
attenuation of the langat tick-borne flavivirus by chimerization with mosquito-borne flavivirus dengue type 4.langat virus (lgt) strain tp21 is the most attenuated of the tick-borne flaviviruses for humans. even though lgt has low-level neurovirulence for humans, it, and its more attenuated egg-passage derivative, strain e5, exhibit significant neurovirulence and neuroinvasiveness in normal mice, albeit less than that associated with tick-borne encephalitis virus (tbev), the most virulent of the tick-borne flaviviruses. we sought to reduce or ablate these viral phenotypes of tp21 and e5 by using a strat ...19989465088
[cross reactions of patients with acute dengue fever to tick-borne encephalitis].sera from 20 patients with acute dengue fever were tested on their cross reactivities to other flaviviruses, especially against tick-borne encephalitis (tbe). one of the test systems used, indirect immunofluorescence (iift), was shown to exhibit strong cross reactivity. the reactivity pattern of sera from patients with pre-existing vaccine-induced antibodies against tbe or yellow fever was found similar to dengue secondary antibody response. in plaque reduction neutralization tests (prnt) no cro ...19979471844
analysis of the structure and folding of the 3' genomic rna of flaviviruses.the structure of the 3' genomic rna of flaviviruses has been analyzed by thermal melting, and by chemical and enzymatic probing of model rnas. the 3' rna had more transitions than could be assigned to individual stem-loops and a transition in the 40-45 degrees c range was assigned to tertiary structure unfolding. in support of this assignment, mutants designed to destabilize the proposed pseudoknot tertiary structure lose the 40-45 degrees c transition. enzyme cleavage of the rna and chemical pr ...19979478204
fulminant hepatitis and the new g/gbv-c flavivirus.a new virus within the family flaviviridae. 'hepatitis' g/gbv-c, has been incriminated by several authors as a causative factor of idiopathic or cryptogenic fulminant hepatitis, a syndrome of presumed viral aetiology. review of worldwide data from 22 studies on 364 cases indicates that g/gbv-c infection is present in approximately 20% of idiopathic cases but a similar or even higher prevalence is detected in fulminant hepatitis of viral b, d or c aetiology, reflecting a high rate of parenteral v ...19989493512
patterns of hepatitis g viraemia and liver disease in haemophiliacs previously exposed to non-virus inactivated coagulation factor concentrates.hepatitis g virus (hgv), a novel flavivirus, has been implicated as a cause of posttransfusion hepatitis. we have performed a longitudinal study in a cohort of haemophiliacs (n = 68) who previously received non-virus inactivated coagulation factor concentrates to assess both patterns of hgv viraemia and any associated liver disease. hepatitis c virus (hcv) rna was present in 58/68 and co-infection with human immunodeficiency virus (hiv) was present in 15/68. hgv rna was detected in 17/68 (25%) s ...19989493578
inhibitory effect of furanonaphthoquinone derivatives on the replication of japanese encephalitis virus.japanese encephalitis still occurs in endemic and epidemic forms over a wide area of asia. although the vaccine against japanese encephalitis virus (jev) is widely used, no antiviral drug has been reported. we used several different kinds of furanonaphthoquinone derivatives and found antiviral activity against jev. especially, 2-methylnaphtho[2,3-b]furan-4,9-dione (fnq3) indicated the highest antiviral activity, followed by 2-(1-hydroxyethyl)-, 5(or 8)-hydroxy-, and 2-methyl-5(or 8)-hydroxy-anal ...19989497071
spontaneous and engineered deletions in the 3' noncoding region of tick-borne encephalitis virus: construction of highly attenuated mutants of a flavivirus.the flavivirus genome is a positive-strand rna molecule containing a single long open reading frame flanked by noncoding regions (ncr) that mediate crucial processes of the viral life cycle. the 3' ncr of tick-borne encephalitis (tbe) virus can be divided into a variable region that is highly heterogeneous in length among strains of tbe virus and in certain cases includes an internal poly(a) tract and a 3'-terminal conserved core element that is believed to fold as a whole into a well-defined se ...19989499069
signal peptidase cleavage at the flavivirus c-prm junction: dependence on the viral ns2b-3 protease for efficient processing requires determinants in c, the signal peptide, and prm.signal peptidase cleavage at the c-prm junction in the flavivirus structural polyprotein is inefficient in the absence of the cytoplasmic viral protease, which catalyzes cleavage at the cooh terminus of the c protein. the signal peptidase cleavage occurs efficiently in circumstances where the c protein is deleted or if the viral protease complex is present. in this study, we used cdna of murray valley encephalitis virus (mve) to examine features of the structural polyprotein which allow this reg ...19989499070
characterization of defective viral rna produced during persistent infection of vero cells with murray valley encephalitis virus.defective interfering viral particles are readily produced in cell culture after a high multiplicity of infection with many animal rna viruses. due to defects that they carry in their genomes, their life cycle needs to be complemented by the helper functions provided by a parental virus which makes them both dependent on and competitive with the parental virus. in many instances, this may cause the abrogation of a lytic cycle of the parental virus, leading to a persistent infection. in this pape ...19989499109
evaluation of recombinant dengue viral envelope b domain protein antigens for the detection of dengue complex-specific antibodies.to increase the specificity of dengue (den) diagnosis based on antibody detection, we have evaluated recombinant proteins as antigens that incorporate most of the b domain of the den virus envelope protein fused to the trpe protein of escherichia coli (trpe-den). a pooled antigen consisting of trpe-den proteins representing all four serotypes of den virus was used in an indirect elisa for the detection of igg or igm antibody. this assay was compared with a standard igg indirect elisa and an igm- ...19989502595
hepatic histology in hepatitis c virus carriers coinfected with hepatitis g virus.a novel flavivirus has been described recently and designated hepatitis g virus (hgv). the virus is transmitted by the parenteral route but it is uncertain whether it is associated with chronic liver disease because liver biopsy is difficult to justify in this group.19989505894
african origin of gb virus c/hepatitis g virus.ninety-four gb virus c/hepatitis g virus (gbv-c/ hgv) rna-positive serum samples were obtained from all over the world. we found that all 15 gbv-c/hgv isolates from the pygmies and the bantu in the central african region had a 12-amino acid indel (i.e. insertion or deletion) in the non-structural protein (ns) 5a region. phylogenetic analyses of the ns5a region, using gbv-a as an outgroup, showed that these 15 isolates had diverged from the common ancestor much earlier than the remaining isolates ...19989512347
[arbovirus infections. from virus, mosquitoes, animals and humans].arboviruses occur throughout the world in plants and animals: reptiles, birds and mammals including man. these relatively recent rna-containing viruses have great evolutionary potential and are a major cause of epidemics. arboviruses exhibit a dual life cycle involving continual transmission to and from the vertebrate host and arthropod vector which ingests or inoculates the agent during blood meals. agents belong to many different viral families and represent an important source of emerging dis ...19979513176
tumor necrosis factor alpha levels in plasma and whole-blood culture in dengue-infected patients: relationship between virus detection and pre-existing specific antibodies.the pathogenesis of dengue hemorrhagic fever (dhf) is not well known, but the role of host factors has been suggested. the level of immunoreactive circulating and cell-generated tumor necrosis factor alpha (tnf alpha) was studied in 35 patients with dhf; its relationship with virus isolation and/or genome detection by reverse transcription polymerase chain reaction (rt-pcr) and specific antibodies were detected by hemagglutination inhibition (hi). large variation of tnf alpha plasma levels was o ...19989515771
neutralizing antibodies protect against lethal flavivirus challenge but allow for the development of active humoral immunity to a nonstructural virus protein.antibody-mediated neutralization of viruses has been extensively studied in vitro, but the precise mechanisms that account for antibody-mediated protection against viral infection in vivo still remain largely uncharacterized. the two points under discussion are antibodies conferring sterilizing immunity by neutralizing the virus inoculum or protection against the development of disease without complete inhibition of virus replication. for tick-borne encephalitis virus (tbev), a flavivirus, trans ...19989525632
emerging viruses.an emerging virus is a term applied to a newly discovered virus, one that is increasing in incidence or with the potential to increase in incidence. many viruses fit into this definition. hiv is the clearest example of a previously unknown virus that has now produced one of the largest pandemics in history. recent advances have occurred in the identification and understanding of new hantaviruses in the americas, causing an acute respiratory disease. the possible causal role of human herpesvirus ...19989529635
antibodies to alphavirus, flavivirus, and bunyavirus arboviruses in house sparrows (passer domesticus) and tree sparrows (p. montanus) in poland.sparrows from central poland were examined by a hemagglutination-inhibition test (titer > or = 20) for the presence of antibodies to arboviruses, between 1995 and 1996. in house sparrows (passer domesticus) (n = 179), antibodies to sindbis, west nile, tick-borne encephalitis, tahyna, and calovo viruses were detected at seroprevalences of 1.1%, 2.8%, 1.1%, 2.8%, and 1.1%, respectively. in tree sparrows (p. montanus) (n = 33), antibodies to the sindbis, west nile, and tahyna viruses were detected ...19989533098
hcv and hgv in b-cell non-hodgkin's lymphoma.a causative role of hepatitis c virus infection (hcv) has been discussed in the pathogenesis of mixed cryoglobulinaemia and in b-cell non-hodgkin's lymphoma. no data are available concerning the newly discovered hepatitis g virus (hgv) and extrahepatic manifestations such as haematological malignancies. but, hcv and hgv most probably belong to the same family of flavivirus. consequently, we looked for the prevalence of hcv, hgv and cryoglobulins in patients with b-cell non-hodgkin's lymphoma.19989537861
comparison of elisa and hi for detection of antibodies against wesselsbron disease virus.a two-graph receiver operating characteristic analysis was done to determine the optimal cut-off value of an indirect enzyme-linked immunosorbent assay (elisa) for detection of antibodies to wesselsbron disease (wsl) virus. when elisa and haemagglutination-inhibition (hi) results of wsl-positive and wsl-negative control sheep sera were compared, the sensitivity of elisa was 97.9% and that of hi, 87.5%, while the specificity of elisa and hi were 95.7% and 100%, respectively. the elisa's superior ...19979551475
nucleic acid vaccines against hepatitis viruses.direct dna intramuscular or intradermal injection of plasmids containing viral genes under the control of viral promoters is an efficient means of stimulating both class i and class ii-mediated antiviral responses. viral hepatitis b and c are suitable candidates for this approach, particularly as therapeutic immunogens for chronically infected individuals. several groups have shown that the s gene of hbv is expressed in murine muscle and stimulates a high titre and long-lasting anti-hbs response ...19989554270
predominance of hla-restricted cytotoxic t-lymphocyte responses to serotype-cross-reactive epitopes on nonstructural proteins following natural secondary dengue virus infection.we examined the memory cytotoxic t-lymphocytic (ctl) responses of peripheral blood mononuclear cells (pbmc) obtained from patients in thailand 12 months after natural symptomatic secondary dengue virus infection. in all four patients analyzed, ctls were detected in bulk culture pbmc against nonstructural dengue virus proteins. numerous cd4+ and cd8+ ctl lines were generated from the bulk cultures of two patients, kpp94-037 and kpp94-024, which were specific for ns1.2a (ns1 and ns2a collectively) ...19989557687
a 68-nucleotide sequence within the 3' noncoding region of simian hemorrhagic fever virus negative-strand rna binds to four ma104 cell proteins.the 3' noncoding region (ncr) of the negative-strand rna [3'(-)ncr rna] of the arterivirus simian hemorrhagic fever virus (shfv) is 209 nucleotides (nt) in length. since this 3' region, designated 3'(-)209, is the site of initiation of full-length positive-strand rna and is the template for the synthesis of the 5' leader sequence, which is found on both full-length and subgenomic mrnas, it is likely to contain cis-acting signals for rna synthesis and to interact with cellular and viral proteins ...19989557724
identification of hepatitis g virus particles in human serum by e2-specific monoclonal antibodies generated by dna immunization.in order to elucidate the structure and morphology of hepatitis g virus (hgv), a recently isolated flavivirus, we generated a panel of eight monoclonal antibodies (mabs) against the putative second envelope protein (e2) following dna immunization. the mabs were shown to be specific for four different epitopes on recombinant e2. mab mc6 was the only antibody able to detect the linear epitope ltggfyepl. in addition, mc6 was able to immunoprecipitate viral particles in human blood samples as detect ...19989557757
[isolation of a complex of tick-borne encephalitis viral proteins by affinity chromatography using monoclonal antibodies to proteins ns5 and ns3].affinity chromatography of lysates of continuous porcine embryo cells infected with tick-borne encephalitis (tbe) virus on sepharose with immobilized monoclonal antibodies to tbe virus proteins ns5 and ns3 results in isolation of a stable protein complex. this complex contains viral proteins ns5, ns3, p49, and, probably, two more cell proteins. this complex is not detected at the early stage of infection, and 24 h after infection its structure does not depend on the specificity of immobilized mo ...19989559535
[some mechanisms of the action of oligonucleotides: stimulation of the immune system and decreased infection of the brain in tickborne encephalitis].morphological changes in the thymus, spleen, and brain are analyzed in white mice injected 16-component oligonucleotide (on) pe16 complementary to the ns3 protein gene sequences of tickborne encephalitis (tbe) virus in doses of 1 to 0.001 nm. on stimulated thymic and splenic cells. besides the stimulating effect, injection of on to mice infected with tbe enhanced the destruction of lymphocytes and boosted the macrophagal activity, which was paralleled by a decrease in the intensity of virus-spec ...19989559536
transmission of hepatitis g virus in patients with angioedema treated with steam-heated plasma concentrates of c1 inhibitor.hepatitis g virus (hgv) is a blood-borne flavivirus that may cause acute and chronic transfusion-transmitted infections. patients with complement component 1 (c1) inhibitor (c1-inh) deficiency may acquire blood-borne infections through infusion of plasma concentrates.19989563413
immunological basis for protection in a murine model of tick-borne encephalitis by a recombinant adenovirus carrying the gene encoding the ns1 non-structural protein.the humoral immune response to flaviviruses is mainly directed to the major envelope protein, e, and a glycosylated non-structural protein, ns1. cell-mediated immune responses, however, appear to be directed mainly against non-structural proteins. experiments described here show that a defective recombinant adenovirus (rad51) containing the gene encoding the ns1 protein of tick-borne encephalitis virus can induce a strong protective immune response against several pathogenic tick-borne flaviviru ...19989568962
definition of the region on ns3 which contains multiple epitopes recognized by dengue virus serotype-cross-reactive and flavivirus-cross-reactive, hla-dpw2-restricted cd4+ t cell clones.the epitopes recognized by six cd4+ cd8- cytotoxic t lymphocyte (ctl) clones established from a dengue-3 virus-immune donor were defined. (i) three ctl clones, jk10, jk34 and jk39, were cross-reactive for dengue virus types 1-4. (ii) one clone, jk28, was cross-reactive for dengue virus types 1-4 and west nile virus. (iii) two clones, jk26 and jk49, were cross-reactive for dengue virus types 1-4, west nile virus and yellow fever virus. the clones, except for jk49, recognized the same epitope on n ...19989568963
wesselsbron disease virus associated with abortions in goats in botswana. 19989576352
mutation in a 17d-204 vaccine substrain-specific envelope protein epitope alters the pathogenesis of yellow fever virus in mice.the heterogeneous nature of the yellow fever (yf) 17d-204 vaccine virus population was exploited in this study to isolate virus variants able to escape neutralization by the 17d-204 vaccine-specific mab 864. the conformational change on the virus surface that resulted in the loss of the mab 864-defined epitope was effected in each variant by a single amino acid mutation in the envelope (e) protein at either position e-305 or e-325. interestingly, both positions were mutated during attenuation of ...19989581778
specific rna aptamers to ns3 protease domain of hepatitis c virus.in order to isolate rna aptamers that bind specifically to ns3 protease domain (delta ns3) of hepatitis c virus, we carried out in vitro selection procedure using rna pool that had 30 n random core region. after repeating nine cycles of selections and amplifications, a pool of rnas that bind specifically to the delta ns3 were selected. a comparative analysis of 45 clones that were isolated from 9th cycle revealed three main classes that contain the conserved loop sequences ganugggac. moreover, t ...19979586087
engineered resistance in aedes aegypti to a west african and a south american strain of yellow fever virus.double subgenomic sindbis (dssin) viruses were engineered to transduce mosquito cells with antisense rna derived either from the premembrane (prm) or polymerase (ns5) coding regions of the 17d vaccine strain of yellow fever virus (yfv). aedes albopictus c6/36 cells were infected at high multiplicities of infection (moi) with each dssin virus. forty-eight hours later, the transduced cells were challenged with an moi of 0.1 of the asibi strain of yfv. at 72-hr postchallenge, the cells were assayed ...19989598458
virus-encoded proteinases of the flaviviridae. 19989603310
[kama, a new virus (flaviviridae, flavivirus, tiulenii antigenic group), isolated from ixodes lividus ticks].three identical strains of a new virus kama (flaviviridae, flavivirus, tyuleny antigenic group) were isolated from ixodes lividus roch, obligate parasites of riparia riparia l. the ticks were collected in june, 1990 in tatarstan on the islands in the basin of the kama river. the strains were examined under electron microscope and by serological tests (neutralization, complement fixation, hemagglutination inhibition, and indirect immunofluorescence). the virus is antigenically related but not ide ...19989606874
[tick-borne encephalitis--etiopathogenesis and implications for public health in poland].tick-borne encephalitis (tbe) belongs to infectious units being under study in poland since over 40 years: clinical, virological, immunological, epidemiological (see eg. fig. 1 of the review) observations succeeded in developing tbe map of poland, and organization of satisfactory diagnostic virological control of the disease. this article covers most important data since the early (1952-1953) expeditions to the endemic districts of poland, studies of human beings, animal reservoir, both wild and ...19989608228
development of rt-pcr for turkey meningoencephalitis virus and partial sequence analysis of the ns5 gene.turkey meningoencephalitis virus (tmev) causes paralysis and mortality in turkeys. because the classical diagnostic methods are complicated, we developed the rt-pcr as a new molecular diagnostic method. since the nucleic acid sequence of tmev is unknown, the first step in developing the rt-pcr relied on conserved sequences of viruses belonging to the flaviviridae family, in which tmev has been classified serologically. using primers from the ns5 gene, three amplification products of tmev rna wer ...19989608667
ilheus virus (flaviviridae, flavivirus) is closely related to japanese encephalitis virus complex.the ilheus (ilh) virus has long been known to belong to group b of the arboviruses. previous attempts to relate it to existing serogroups within the flavivirus genus using conventional serological techniques such as hemagglutination inhibition, neutralization and complement fixation tests have been inconclusive. we have first used denaturing gel electrophoresis to estimate the molecular weight of immunoprecipitated radiolabeled viral proteins and the cross-reactivity among ilh proteins and hyper ...19979612722
human disease caused by an arbovirus closely related to ilheus virus: report of five cases.we report five cases of human disease caused by arbovirus in 5 patients from the state of são paulo, brazil, residing in the municipalities of osasco, atibaia, guarujá, and the capital são paulo, respectively. one of the patients resides in são luis, capital of the state of maranhão. the sites of infection probably were the states of paraná and goiás, both in cave regions, the state of amazonas, and rondônia in two cases. laboratory tests for malaria were negative and 1 patient showed a positive ...19979612726
prevalence of infection with hepatitis g virus among various groups in thailand.two research groups recently and independently, isolated a hepatotropic flavivirus from human sera. the two viruses, named gb virus c and hepatitis g virus (hgv), were subsequently discovered to represent the same virus, which was associated with acute and chronic hepatitis of the non-a-e type. the prevalences of infection with hgv have now been investigated in various groups of the thai population, some of which [e.g. thalassaemic children, patients with chronic liver disease, carriers of antib ...19989614458
encapsidation of the flavivirus kunjin replicon rna by using a complementation system providing kunjin virus structural proteins in trans.kunjin virus (kun) replicon rna was encapsidated by a procedure involving two consecutive electroporations of bhk-21 cells, first with kun replicon rna c20dxrep (with prme and most of c deleted) and about 24 h later with a recombinant semliki forest virus (sfv) replicon rna(s) expressing kun structural proteins. the presence of kun replicon rna in encapsidated particles was demonstrated by its amplification and expression in newly infected bhk-21 cells, detected by northern blotting with a kun-s ...19989621059
the ns5a/ns5 proteins of viruses from three genera of the family flaviviridae are phosphorylated by associated serine/threonine kinases.phosphorylation of the expressed ns5a protein of hepatitis c virus (hcv), a member of the hepacivirus genus of the family flaviviridae, has been demonstrated in mammalian cells and in a cell-free assay by an associated kinase activity. in this report, phosphorylation is also shown for the ns5a and ns5 proteins, respectively, of bovine viral diarrhea virus (bvdv) and yellow fever virus (yf), members of the other two established genera in this family. phosphorylation of bvdv ns5a and yf ns5 was ob ...19989621090
[studying the possibility of respiratory immunization against tick-borne encephalitis].there are known 3 likely mechanisms of virus conveyance into the central nervous system (cns). these include hematogenic penetration, spread along the peripheral nerves, and the olfactory pathway which begins from the infected olfactory neuroepithelial cells. the possibility of viral spread into cns via the olfactory pathway was shown for the representatives of togaviruses, herpesviruses, coronaviruses, rhabdoviruses, and for some others. this study suggests that the olfactory pathway of viral c ...19989633235
subcellular localization and some biochemical properties of the flavivirus kunjin nonstructural proteins ns2a and ns4a.in a previous study on the replication of kunjin virus using immunoelectron microscopy (e. g. westaway, j. m. mackenzie, m. t. kenney, m. k. jones, and a. a. khromykh, 1997, j. virol. 71, 6650-6661), ns1 and ns3 were found associated with double-stranded rna (dsrna) within vesicle packets (vp) in infected vero cells, suggesting that these induced membrane structures may be the cytoplasmic sites of rna replication. ns2b and ns3 (comprising the virus-encoded protease) were colocalized within disti ...19989636360
genetically determined resistance to flavivirus infection in wild mus musculus domesticus and other taxonomic groups in the genus mus.inherited resistance to flaviviruses in laboratory mice is a rare trait conferred by an autosomal dominant gene (flvr). to provide information on genetic resistance to flaviviruses in wild mice, we analysed (i) wild m. m. domesticus trapped in australia, and (ii) mice representing other species and subspecies in the genus mus. mice were screened for resistance relative to c3h/hej mice by intracerebral challenge with murray valley encephalitis virus or yellow fever virus, and breeding studies wer ...19989638142
genetic control of host resistance to flavivirus infection in animals.flaviviruses are small, enveloped rna viruses which are generally transmitted by arthropods to animals and man. although flaviviruses cause important diseases in domestic animals and man, flaviviral infection of animals which constitute the normal vertebrate reservoir may be mild or sub-clinical, which suggests that some adaptation between virus and host may have occurred. while this possibility is difficult to study in wild animals, extensive studies using laboratory mice have demonstrated the ...19989638813
gb virus c: a novel pathogen or a curiosity for virologists?the recently identified gb virus c is a flavivirus related to the hepatitis c virus. it appears quite prevalent in the general population and especially in individuals at risk of parenteral transmission. many questions remain, most importantly the pathogenic role of the virus. it is unlikely that this virus has a major role in hepatic disease.19989639948
a presumptive case of fatal murray valley encephalitis acquired in alice springs.a presumptive case of murray valley encephalitis (mve) acquired in alice springs in march 1997 is reported. the patient subsequently died in mackay. the diagnosis of murray valley encephalitis was supported by the detection of flavivirus igm in cerebrospinal fluid. low titres of igm specific to murray valley encephalitis and alfuy were detected in a single serum sample. the patient's travel movements indicate that his infection was acquired in the alice springs vicinity. this conclusion was furt ...19989648367
dengue or kokobera? a case report from the top end of the northern territory.in early april 1998, the centre for disease control in darwin was notified of a possible case of dengue which appeared to have been acquired in the northern territory. because dengue is not endemic to the northern territory, locally acquired infection has significant public health implications, particularly for vector identification and control to limit the spread of infection. dengue igm serology was positive on two occasions, but the illness was eventually presumptively identified as kokobera ...19989648368
critical point mutations for hepatitis c virus ns3 proteinase.the hepatitis c virus ns3 proteinase plays an essential role in processing of hcv nonstructural precursor polyprotein. to detect its processing activity, we developed a simple trans-cleavage assay. two recombinant plasmids expressing the ns3 proteinase region and a chimeric substrate polyprotein containing the ns5a/5b cleavage site between maltose binding protein and protein a were co-introduced into escherichia coli cells. the proteinase processed the substrate at the single site during their p ...19989656998
monoclonal antibody mapping of the envelope glycoprotein of the dengue 2 virus, jamaica.although dengue (den) virus is the etiologic agent of dengue fever, the most prevalent vector-borne viral disease in the world, precise information on the antigenic structure of the dengue virion is limited. we have prepared a set of murine monoclonal antibodies (mabs) specific for the envelope (e) glycoprotein of den 2 virus and used these antibodies in a comprehensive biological and biochemical analysis to identify 16 epitopes. following domain nomenclature developed for the related flavivirus ...19989657950
recombinant dengue virus type 1 ns3 protein exhibits specific viral rna binding and ntpase activity regulated by the ns5 protein.the full-length dengue virus ns3 protein has been successfully expressed as a 94-kda gst fusion protein in escherichia coli. treatment of the purified fusion protein with thrombin released a 68-kda protein which is the expected molecular mass for the den1 ns3 protein. the identity of this protein was confirmed by western blotting using dengue virus antisera. two related activities of the recombinant ns3 protein were characterized, which were the binding of the protein to the 3'-noncoding region ...19989657959
hepatitis g infection: role in cryptogenic chronic liver disease and primary liver cell cancer in the uk. trent hepatitis c virus study group.hepatitis g virus (hgv) is a flavivirus that can cause acute hepatitis and persistent infection but its role in chronic liver disease or primary liver cancer is unproven. in this study we have examined the prevalence of hgv rna in the serum of patients with hepatitis c virus (hcv) infection and in patients with cryptogenic chronic liver disease, including non-alcoholic steatohepatitis (nash), and in patients with hcv-related hepatocellular carcinoma (hcc) and hcc arising in patients with cryptog ...19989658369
the metal binding site of the hepatitis c virus ns3 protease. a spectroscopic investigation.the ns3 region of the hepatitis c virus encodes for a serine protease activity, which is necessary for the processing of the nonstructural region of the viral polyprotein. the minimal domain with proteolytic activity resides in the n terminus, where a structural tetradentate zinc binding site is located. the ligands being been identified by x-ray crystallography as being three cysteines (cys97, cys99, and cys145) and one histidine residue (his149), which is postulated to coordinate the metal thr ...19989668049
gb virus c/hepatitis g virus (gbv-c/hgv) infection in chiang mai, thailand, and identification of variants on the basis of 5'-untranslated region sequences.by using reverse transcription and pcr for ns3 and 5'-untranslated regions (5'utr) of the viral genome, prevalence of gb virus c/hepatitis g virus (gbv-c/hgv) infection in chiang mai, thailand, was studied. high prevalence of gbv-c/hgv infection was observed among intravenous drug users (32%) and hemodialyzed patients (25%). the prevalence was also considerably high among patients with chronic liver disease, such as chronic hepatitis (9%), liver cirrhosis (12%) and hepatocellular carcinoma (10%) ...19979672605
vaccination against tick-borne encephalitis virus, a flavivirus, prevents disease but not infection, although viremia is undetectable.by adoptive transfer of sera or immunoglobulin preparations, vaccine-induced protection against tbev has been demonstrated to be mediated by antibodies to the surface protein of tbev, glycoprotein e. nevertheless, the mechanism of vaccine-induced protection against tbev remains unclear. protection by e antibodies without in vitro neutralization was shown by one group, whereas others found a correlation between protection in vivo and neutralization in vitro. here, the authors confirm in a mouse m ...19989682362
low prevalence of hepatitis g virus antibodies in glomerular diseases.a possible agent for human non-a-e hepatitis has been identified and named hepatitis g virus (hgv). hgv is also a flavivirus, and the clinical characteristics and risk factors of hgv infection may be similar to those of hepatitis c virus infection. hepatitis c virus infection may manifest as a primary glomerulonephritis. the aim of this study is to evaluate the prevalence of serum hgv rna in 98 adult patients with biopsy-proven glomerular diseases. we found that only 3 patients (3%) out of 98 wi ...19989689165
trans-complementation of flavivirus rna polymerase gene ns5 by using kunjin virus replicon-expressing bhk cells.a bhk cell line persistently expressing a kunjin (kun) virus replicon rna (repbhk, similar to our recently described me/76neo bhk cell line [a. a. khromykh and e. g. westaway, j. virol. 71:1497-1505, 1997]) was used for rescue and propagation of kun viruses defective in the rna polymerase gene (ns5). a new infectious full-length kun virus cdna clone, flsdx, prepared from our previously described cdna clone pakun (a. a. khromykh and e. g. westaway, j. virol. 68:4580-4588, 1994) and possessing app ...19989696822
identification of specific nucleotide sequences within the conserved 3'-sl in the dengue type 2 virus genome required for replication.the flavivirus genome is a positive-stranded approximately 11-kb rna including 5' and 3' noncoding regions (ncr) of approximately 100 and 400 to 600 nucleotides (nt), respectively. the 3' ncr contains adjacent, thermodynamically stable, conserved short and long stem-and-loop structures (the 3'-sl), formed by the 3'-terminal approximately 100 nt. the nucleotide sequences within the 3'-sl are not well conserved among species. we examined the requirement for the 3'-sl in the context of dengue virus ...19989696848
[preparation and properties of monoclonal antibodies to tick-borne encephalitis viral nonstructural proteins].hybridomas secreting monoclonal antibodies (mab) to tick-borne encephalitis (tbe) virus are obtained. immunodiffusion showed that 3 mabs to tbe protein ns3 belong to class igm and the rest to igg1. mabs to tbe protein ns1 were tested in hemagglutination inhibition, complement fixation, neutralization, and protection tests. only 1 hybridoma produced mab specific for protein ns1 of tbe strain sofyin, the rest reacted with the common antigenic determinants of nonstructural tbe complex.19989702814
epidemiology of the hepatitis c virus.according to who estimations, about 3% of the world population may be infected with the hepatitis c virus. the relative prevalences of subtypes of this virus vary in different geographic areas. the main known routes of transmission are parenteral; intravenous drug abuse, contaminated injection devices and receipt of unscreened blood. sexual, vertical, household and nosocomial transmissions may occur, but seem to be rare. the risk of screened blood or blood products is now almost eliminated, but ...19989704437
a rapid fluorescent focus inhibition test for detection of neutralizing antibodies to tick-borne encephalitis virus.tick borne encephalitis (tbe), is endemic in several countries in central and northern europe, in the baltic states and in russia. vaccination has been shown to lower efficiently the number of cases of this potentially very serious disease. however, the possibility to assess the neutralizing antibody response after clinical disease or vaccination has been hampered by the lack of easy and specific tests. we developed a rapid fluorescent focus inhibition test (rffit) and compared it with a standar ...19989705177
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