design of selective eglin inhibitors of hcv ns3 proteinase.hepatitis c virus (hcv) infection is a major health problem that leads to cirrhosis and hepatocellular carcinoma in a substantial number of infected individuals, estimated to be 100-200 million worldwide. unfortunately, immunotherapy or other effective treatments for hcv infection are not yet available, and interferon administration has limited efficacy. different approaches to hcv therapy are being explored, and these include inhibition of the viral proteinase, helicase, and rna-dependent rna p ...19989708981
yellow fever 17d vaccine virus isolated from healthy vaccinees accumulates very few mutations.the live attenuated yellow fever (yf) vaccine strain 17d is one of the safest vaccines in use today with only 22 cases of reversion to virulence documented from over 300 million doses administered. we have isolated virus in cell culture from sera of six volunteers who received 17d vaccine and found that very few nucleotide mutations were detected in the consensus sequence of the entire genome of each of the serum viruses. moreover, most of these mutations accumulated in the non-structural protei ...19989712515
detection in chimpanzees of a novel flavivirus related to gb virus-c/hepatitis g virus.infection with hepatitis g virus (hgv) or gb virus-c (gbv-c) is widely distributed in human populations. viruses related to gbv-c/hgv have been recovered from several new world primate species, including tamarins, owl monkeys and marmosets. to understand more about the relationship between gb viruses and their hosts, we used primers from the 5' non-coding (5'nc), non-structural 3 (ns3) and ns5 regions in nested polymerase chain reactions to screen for related viruses infecting non-captive chimpa ...19989714234
mutation in ns5 protein attenuates mouse neurovirulence of yellow fever 17d vaccine virus.the 17d-204 vaccine manufactured in south africa (17d-204-sa) and a large plaque variant (17d-lp) derived from it were highly virulent in adult mice. the ld50 of 17d-lp virus was 0-2 p.f.u. for mice following intracerebral inoculation. in comparison, a medium plaque variant derived from 17d-lp, termed 17d-mp virus, was found to be attenuated in adult mice following the same route of inoculation (> 10(4) p.f.u./ld50). replication of 17d-mp virus was decreased in infected mouse brains compared to ...19989714237
establishment and characterization of japanese encephalitis virus-specific, human cd4(+) t-cell clones: flavivirus cross-reactivity, protein recognition, and cytotoxic activity.we analyzed the cd4(+) t-lymphocyte responses of two donors who had received japanese encephalitis virus (jev) vaccine 6 or 12 months earlier. bulk culture proliferation assays showed that peripheral blood mononuclear cells (pbmc) responded to jev antigens (ag) but also responded at lower levels to west nile virus (wnv) and dengue virus type 1, 2, and 4 (d1v, d2v, and d4v, respectively) ag. five jev-specific cd4(+) human t-cell clones and one subclone were established from pbmc of these two dono ...19989733842
an advisory committee statement (acs). committee to advise on tropical medicine and travel (catmat). statement on japanese encephalitis vaccine. 19989735509
west nile encephalitis epidemic in southeastern romania.west nile fever (wnf) is a mosquito-borne flavivirus infection endemic in africa and asia. in 1996, the first major wnf epidemic in europe occurred in romania, with a high rate of neurological infections. we investigated the epidemic to characterise transmission patterns in this novel setting and to determine its origin.19989737281
determination of dengue virus serotypes in individual aedes aegypti mosquitoes in aedes aegypti mosquitoes were collected in puerto triunfo, central colombia, where dengue is endemic, during a six month period. viral infection within the head of each individual mosquito was identified by an immunofluorescent assay (ifa) using a flavivirus-specific monoclonal antibody. the dengue virus serotype, present in each flavivirus-positive specimen, was then determined in portions of the remaining thorax using ifas with serotype-specific monoclonal antibodies. among 2065 female a ...19989737600
immune mediated and inherited defences against flaviviruses.flavivirus infection elicits an abundant immune response in the host which is directed against a number of the viral proteins. resistance to flavivirus-induced disease can also be controlled via a non-immune mechanism involving the product of a naturally occurring murine gene, flv.19989741638
the conformation of hepatitis c virus ns3 proteinase with and without ns4a: a structural basis for the activation of the enzyme by its cofactor.hepatitis c virus (hcv) ns3 proteinase activity is required for the release of hcv nonstructural proteins and is thus a potential antiviral target. the enzyme requires a protein cofactor ns4a, located downstream of ns3 on the polyprotein, for activation and efficient processing.19989741640
defective adenoviruses as novel vaccines for the flaviviridae.vaccines against many flaviviruses, such as japanese encephalitis virus (jev), yellow fever virus (yfv) and tick-borne encephalitis virus (tbev), have been successfully used for many years. other diseases such as dengue fever (df) and hepatitis c are still major public health problems as no licensed vaccines are in use.19989741645
high prevalence of gb virus c/hepatitis g virus infection among homosexual men infected with human immunodeficiency virus type 1: evidence for sexual virus c/hepatitis g virus (gbv-c/hgv), a recently discovered orphan flavivirus, is distantly related to hepatitis c virus (hcv). although both gbv-c/hgv and hcv can be transmitted by the parenteral route, their principal modes of transmission and associated risk behaviors may differ. using reverse transcription-polymerase chain reaction, the 5'-noncoding regions of gbv-c/hgv and hcv were amplified from plasma or sera of 209 individuals infected with human immunodeficiency virus type 1 (hiv-1) ...19989746067
development of viremia and humoral and cellular parameters of immune activation after vaccination with yellow fever virus strain 17d: a model of human flavivirus monitor early and late events of immune system activation after primary and secondary flavivirus infection, 17 healthy persons were vaccinated with the standard 17d vaccine virus strain of yellow fever (yf). twelve of these persons had not received yf vaccine previously and 5 had been vaccinated once at least 10 years before. viremia and various parameters of humoral and cellular immune activation were followed daily for 7 days and weekly thereafter. viremia was detected by reverse transcript ...19989746073
immunoglobulin m-capture biotin-streptavidin enzyme-linked immunosorbent assay for detection of antibodies to dengue viruses.a biotin-streptavidin system was adapted to an igm-capture elisa for detection of dengue antibodies in human sera. to develop this assay, high titers of antibodies to flavivirus were purified by ion-exchange chromatography (deae-cellulose) and labeled with biotin. heavy chain-specific goat anti-human igm was first bound to the wells of a polystyrene microtiter plate, followed by binding of igm in test specimens, and the use of tetravalent dengue antigens (dengue 1-4), biotin-labeled anti-flavivi ...19989749624
identification of brazilian flaviviruses by a simplified reverse transcription-polymerase chain reaction method using flavivirus universal primers.we report a simplified reverse transcription-polymerase chain reaction (rt-pcr) method for identification of brazilian flaviviruses based on the patterns of electrophoretic separation of the amplicons. the rt-pcr was done on the culture fluids of aedes albopictus c6/36 cells infected with brazilian flaviviruses, without previous extraction of viral rna, using flavivirus universal primers that anneal to highly conserved sequences within the nonstructural protein 5 and 3'- non translated region of ...19989749625
tick-borne encephalitis and its prevention in hungary.tick-borne encephalitis (tbe) has been registered in hungary since 1977. in the last four years a moderate decrease of cases was observed. most cases belong to the age group of 30-39 years, and the number of males is twice as high as that of the females among the tbe cases. the efficacy of tbe vaccination was proven also in field trials. the use of the specific hyperimmune gamma-globulins for postexposure prophylaxis is effective. the need to create an international standard for tbe vaccine is d ...19989769651
identification of australian arboviruses in inoculated cell cultures using monoclonal antibodies in elisa using a panel of specific monoclonal antibodies was developed to identify all alpha and flaviviruses isolated from mosquitoes caught throughout australia. this technique is sensitive and rapid and is more specific than the traditional methods used to identify flaviviruses. the ability to identify unknown virus isolates from field-caught mosquitoes quickly and accurately improves the efficiency of arbovirus surveillance programs and allows health authorities to give an early warning of a ...19989770194
dna-based and alphavirus-vectored immunisation with prm and e proteins elicits long-lived and protective immunity against the flavivirus, murray valley encephalitis virus.the immunogenicity and protective efficacy of dna-based vaccination with plasmids encoding the membrane proteins prm and e of the flavivirus murray valley encephalitis virus (mve) were investigated. gene gun-mediated intradermal delivery of dna encoding the prm and e proteins elicited long-lived, virus-neutralising antibody responses in three inbred strains of mice and provided protection from challenge with a high titer inoculum of mve. intramuscular dna vaccination by needle injection also ind ...19989770429
generation and characterization of japanese encephalitis virus specific monoclonal antibodies.monoclonal antibodies (moabs) specifically against japanese encephalitis virus (jev) were generated by fusion of immunized mouse spleen cells with ns-1 myeloma cells. nakayama-nih (na) and three taiwan local strains of jev, i.e., tl isolated from a patient's brain in 1965, nt109 (je7) isolated from cx. tritaeniorhynchus in 1985, and rp9, a plaque purified clone of nt109, were used in the immunization. the specificities of moabs were determined by immunoprecipitation and western blotting, using j ...19959774991
[japanese encephalitis: an exceptional imported arbovirus]. 19989779048
hepatitis g virus and related flaviviruses: pathogens or passengers? 19989779360
west nile virus envelope proteins: nucleotide sequence analysis of strains differing in mouse neuroinvasiveness.several neuroinvasive and non-neuroinvasive west nile (wn) viruses were characterized by nucleotide sequencing of their envelope (e) protein regions. prolonged passage in mosquito cells caused loss of neuroinvasiveness and acquisition of an n-linked glycosylation site, which is utilized. limited passage in cell culture also caused glycosylation but not attenuation, suggesting that glycosylation may not be directly responsible for attenuation and that a second mutation (l68 --> p) may also be inv ...19989780042
the epidemiology of louping-ill, a tick borne infection of red grouse (lagopus lagopus scoticus).the epidemiology of louping-ill in red grouse was studied in northern britain concentrating on the possible role of other species and mechanisms of disease persistence. this tick borne viral disease caused heavy mortality in red grouse, particularly chicks. louping-ill induced mortality reduced the strength of the density dependence that generates the tendency of grouse populations to cycle and in some populations may cause population sinks. four routes of transmission were examined and non-vira ...19979802086
[antibodies against the west nile virus and other arthropod-transmitted viruses in the ebro delta region].the west nile virus (wnv) is a flavivirus which is transmitted to man by means of different species of mosquitoes and causes outbreaks and sporadic cases of illness in different regions of the old world, including the mediterranean basin. europe's wetlands which comprise a stopping-off point for birds migrating from africa are high-risk areas as regards this infection, as well as other arthropod-borne virus infections.19989810831
[protein e 98-113 sequence is a fusion site of tick-borne encephalitis virus with cellular membrane].the synthetic peptide with the conservative 98-113 sequence of protein e of tick-borne encephalitis virus was studied in order to elucidate its role in the functioning of flaviviruses. the peptide was shown to inhibit the in vitro infection of macrophages with the virus. an antibody that specifically binds this peptide was found among the set of monoclonal antibodies produced against protein e. this antibody was found to prevent penetration of the virus into liposomes. a correlation was found be ...19989813732
detection of specific antibodies in saliva during dengue infection.saliva was collected prospectively from patients presenting with suspected dengue infection 4 to 8 days after the onset of symptoms and assayed by a commercial dengue immunoglobulin m (igm) and igg capture enzyme-linked immunosorbent assay (elisa) (panbio dengue duo elisa). laboratory diagnosis was based on virus isolation and on hemagglutination inhibition (hai) assay and an in-house igm and igg capture elisa. with a positive result defined as either salivary igm or igg levels above the cutoff ...19989817913
growth restriction of dengue virus type 2 by site-specific mutagenesis of virus-encoded glycoproteins.the three flavivirus glycoproteins prm, e and ns1 are formed by post-translational cleavage and are glycosylated by the addition of n-linked glycans. ns1 may form homodimers, whereas e may form homodimers, homotrimers or heterodimers (prm-e). modification of these processes by mutagenesis of the proteins has the potential to generate viruses that are restricted in growth and are possible vaccine candidates. using an sv40-based expression system, we previously analysed dimerization and secretion ...19989820138
prevalence of hepatitis g-virus infection in alcohol abusing patients with and without liver cirrhosis.hepatitis g (gbv-c/hgv) is an rna-virus belonging to the flavivirus family and is capable of inducing hepatitis in rare cases. its importance as a co-factor in the pathogenesis of liver disease needs to be clarified.19989823622
[the morphological characteristics of cell death in different forms of acute tick-borne encephalitis].the study was aimed to identify different types of cell death in monkey brain in flavivirus experimental encephalitis. 10 brain areas most vulnerable ("indicator") of the disease in its different forms (symptomless, intermediate and severe) were examined in animals infected intracerebrally with viruses of tick-borne encephalitis. cells of ectodermal and mesenchymal origin displayed apoptosis that was most pronounced in intermediate form of the severity of the disease. apoptosis was not character ...19989826821
evaluation of an igm immunoblot kit for dengue diagnosis.a commercial igm immunoblot kit was evaluated for dengue diagnosis with a panel of serum specimens collected from patients in a dengue endemic area. the kit is not recommended for use in its present form because of its undesirable rate of false-positive results. however, by substituting internal controls with the reference positive and negative controls that are more representative of those seen in endemic areas and by modifying the positive and negative scoring criteria, sensitivity and specifi ...19989840593
in vitro-synthesized infectious rna as an attenuated live vaccine in a flavivirus virus vaccines have in many cases proven to be an extremely effective tool for the prevention of viral diseases. however, the production of conventional live vaccines in eukaryotic cell cultures has many disadvantages, including the potential for contamination with adventitious agents and genetic alterations during propagation, making it necessary to do extensive testing before distribution. based on results obtained with a flavivirus (tick-borne encephalitis virus) in an experimental anima ...19989846585
analysis of murine cd8(+) t-cell clones specific for the dengue virus ns3 protein: flavivirus cross-reactivity and influence of infecting serotype.serotype-cross-reactive dengue virus-specific cytotoxic t lymphocytes (ctl) induced during a primary dengue virus infection are thought to play a role in the immunopathogenesis of dengue hemorrhagic fever (dhf) during a secondary dengue virus infection. although there is no animal model of dhf, we previously reported that murine dengue virus-specific ctl responses are qualitatively similar to human dengue virus-specific ctl responses. we used balb/c mice to study the specificity of the ctl respo ...19999847344
[dengue: a re-emerging disease. a clinical and epidemiological study in 57 spanish travelers].dengue infection is nowadays considered a re-emergent disease. it has a worldwide tropical and subtropical distribution. the dengue virus in a member of the flavivirus family composed by 4 different serotypes. the virus is transmitted by mosquitos of the aedes genus. with the increment of travels to the endemic areas, dengue is now observed frequently in our country. we analyzed 57 patients, 30 with imported dengue (id) and 27 with dengue fever suffered during the trip (ddt). this series is comp ...19989859093
affinity labelling of the tick-borne encephalitis virus rna replicase proteins by 4-n-exo-base-substituted photoreactive ctp analogs.4-n-exo-base-substituted photoreactive analogs of ctp were designed and synthesized. two flavivirus proteins ns5 and ns3 are shown to be labelled after rna synthesis in the presence of the analogs, irradiation by uv-light (313 nm) and subsequent [alpha-32p]ntp incorporation.19989871542
japanese encephalitis. 19989876271
a phylogenetically conserved stem-loop structure at the 5' border of the internal ribosome entry site of hepatitis c virus is required for cap-independent viral translation.hepatitis c virus (hcv) initiates translation of its polyprotein under the control of an internal ribosome entry site (ires) that comprises most of the 341-nucleotide (nt) 5' nontranslated rna (5'ntr). a comparative analysis of related flaviviral sequences suggested that an rna segment for which secondary structure was previously ill defined (domain ii, nt 44 to 118) forms a conserved stem-loop that is located at the 5' border of the hcv ires and thus may function in viral translation. this pred ...19999882318
prevalence and patterns of hgv/gbv-c infection in patients with suspected hcv-related hepatitis.hepatitis g virus (hgv) is a recently described hepatotropic parenterally transmitted flavivirus. the presence of hgv was tested in 61 patients with a request for confirmation of hcv active infection. thirty-two patients were in haemodialysis and 29 were referred from wards other than nephrology. active hcv and hgv infections were determined by detection of their viral rna in serum. evaluation of previous hgv infection was carried out by detection of antibodies to e2 antigen. hcv prevalence was ...19989923019
hepatitis g virus infection in lymphoma and in blood determine whether the recently described flavivirus, hepatitis g virus (hgv), might contribute to the pathogenesis of lymphoma by testing for the presence of hgv rna in sera from patients attending lymphoma clinics; to compare the incidence of hgv rna in lymphoma patients with that in normal blood donors; and to look for potential risk factors for hgv infection and for evidence of hepatic disease in the hgv positive patients.19989930072
localizations of ns3 and e proteins in mouse brain infected with mutant strain of japanese encephalitis virus.infection with a mutant japanese encephalitis virus (jev) strain rp-2ms showed reduced neurovirulence than wild type or rp-9 strains after inoculation in balb/c mice. however, higher intracellular viral titer was detected in rp-2ms infected cultured cells. localizations of non-structural 3 (ns3) and envelope (e) proteins were demonstrated by immunocytochemistry. ns3 protein was primarily found in the pyramidal neurons in cerebrum, in the molecular and granular layers of cerebellum. neither e nor ...19989930192
sequence analysis and genetic classification of tick-borne encephalitis viruses from europe and asia.the epidemiology of tick-borne encephalitis virus was investigated by comparative sequence analysis of virus strains isolated in endemic areas of europe and asia. phylogenetic relationships were determined from the nucleotide and amino acid sequences of the major envelope (e) protein of 16 newly sequenced strains and nine previously published sequences. three genetic lineages could be clearly distinguished, corresponding to a european, a far eastern and a siberian subtype. amino acids characteri ...19999934700
[prevalence of flavivirus antibodies in young voluntary recruits to military service in the province of formosa, argentina].the aim of the present study was to investigate the seroprevalence to flavivirus, in young people living in risk areas. we analyzed 189 human sera from 3 towns in the province of formosa. this area corresponds to the border that limits brasil and paraguay and the aim was to search for a possible introduction of dengue and yellow fever from these countries. serological tests such as haemagglutination inhibition (hi), complement fixation (cf) and neutralization (nt) were performed using st. louis ...19989950038
mutant influenza viruses with a defective ns1 protein cannot block the activation of pkr in infected cells.a short model genome rna and also the genome rna of influenza a virus bearing both 5'- and 3'-terminal common sequences activated the interferon-induced double-stranded-rna-dependent protein kinase, pkr, by stimulating autophosphorylation in vitro. the activated pkr catalyzed phosphorylation of the alpha subunit of eucaryotic translation initiation factor 2 (eif2alpha). the ns1 protein efficiently eliminated the pkr-activating activity of these rnas by binding to them. two mutant ns1 proteins, e ...19999971827
gb virus c/hepatitis g virus infection in hemodialysis patients: determination of seroprevalence by a four-antigen recombinant immunoblot virus c/hepatitis g virus (gbv-c/hgv) was identified recently and only two assays, consisting of a single recombinant protein, have been described for determination of the seroprevalence of this virus. an immunoblot assay was devised, which contains four recombinant gbv-c/hgv proteins. in this study, serum samples from 154 patients on maintenance hemodialysis were examined to assess the rate of seroreactivity against gbv-c/hgv. all sera were tested for the presence of antibodies by an in-hous ...199910022792
dengue virus ns3 serine protease. crystal structure and insights into interaction of the active site with substrates by molecular modeling and structural analysis of mutational effects.the mosquito-borne dengue viruses are widespread human pathogens causing dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, placing 40% of the world's population at risk with no effective treatment. the viral genome is a positive strand rna that encodes a single polyprotein precursor. processing of the polyprotein precursor into mature proteins is carried out by the host signal peptidase and by ns3 serine protease, which requires ns2b as a cofactor. we report here the crystal str ...199910026173
[molecular biology of dengue virus].in venezuela the problem of dengue infection has become worst during the last decade, turning the country into an hyperendemic region where three of the four serotypes co-circulate. the dengue has become a problem of public health, so the knowledge of the virus, its life cycle and characteristics, as well as the different aspects related with its biology are extremely important to fight the virus and for the develop of a vaccine. in a general way, the present work describes different aspects rel ...199810030047
[laboratory diagnosis to dengue virus infections].currently, laboratory diagnosis of dengue virus infection has a special importance because of its emerging character, showing a great geographic propagation of viral activity through out the american continent. in general, the laboratory diagnosis of dengue infections is similar to other human infecting viruses, the difference and difficulty of the process lies in the cross reaction activity with other flavivirus that can co-exist in the same region. the effectiveness of the diagnosis depends on ...199810030051
use of a fluorescence plate reader for measuring kinetic parameters with inner filter effect correction.a general method is presented here for the determination of the km, kcat, and kcat/km of fluorescence resonance energy transfer (fret) substrates using a fluorescence plate reader. a simple empirical method for correcting for the inner filter effect is shown to enable accurate and undistorted measurements of these very important kinetic parameters. inner filter effect corrected rates of hydrolysis of a fret peptide substrate by hepatitis c virus (hcv) ns3 protease at various substrate concentrat ...199910036138
sequence heterogeneity within three different regions of the hepatitis g virus genome.two sets of primers derived from the 5'-terminal region and the ns5 region of the hepatitis g virus (hgv) genome were used to amplify pcr fragments from serum specimens obtained from different parts of the world. all pcr fragments from the 5'-terminal region (5'-pcr, n = 56) and from the ns5 region (ns5-pcr, n = 85) were sequenced and compared to corresponding published hgv sequences. the range of nucleotide sequence similarity varied from 74 and 78% to 100% for 5'-pcr and ns5-pcr fragments, res ...199910069950
noncytopathic flavivirus replicon rna-based system for expression and delivery of heterologous genes.noncytopathic replicons of the flavivirus kunjin (kun) were employed for expression and delivery of heterologous genes. replicon vector c20dx2arep, containing a unique cloning site followed by the sequence of 2a autoprotease of foot-and-mouth disease virus, was constructed and used for expression of a number of heterologous genes including chloramphenicol acetyltransferase (cat), green fluorescent protein (gfp), beta-galactosidase, glycoprotein g of vesicular stomatitis virus, and the core and n ...199910069962
yellow fever/japanese encephalitis chimeric viruses: construction and biological properties.a system has been developed for generating chimeric yellow fever/japanese encephalitis (yf/je) viruses from cdna templates encoding the structural proteins prm and e of je virus within the backbone of a molecular clone of the yf17d strain. chimeric viruses incorporating the proteins of two je strains, sa14-14-2 (human vaccine strain) and je nakayama (je-n [virulent mouse brain-passaged strain]), were studied in cell culture and laboratory mice. the je envelope protein (e) retained antigenic and ...199910074160
the serine protease and rna-stimulated nucleoside triphosphatase and rna helicase functional domains of dengue virus type 2 ns3 converge within a region of 20 amino acids.ns3 protein of dengue virus type 2 has a serine protease domain within the n-terminal 180 residues. ns2b is required for ns3 to form an active protease involved in processing of the viral polyprotein precursor. the region carboxy terminal to the protease domain has conserved motifs present in several viral rna-stimulated nucleoside triphosphatase (ntpase)/rna helicases. to define the functional domains of protease and ntpase/rna helicase activities of ns3, full-length and amino-terminal deletion ...199910074162
[seroprevalence of central european tick-borne encephalitis in the lorraine region].central european encephalitis, caused by the tick-borne encephalitis virus (tbev), is exceptional in france. most cases have been described in alsace. as 2 cases of tick-borne encephalitis were diagnosed in the nancy region, a seroepidemiological survey was conducted in the lorraine region (meurthe & moselle, moselle, vosges, meuse) in 1996.199910076595
mosquito feeding modulates th1 and th2 cytokines in flavivirus susceptible mice: an effect mimicked by injection of sialokinins, but not demonstrated in flavivirus resistant mice.culex pipiens and aedes aegypti mosquitoes were fed on c3h/hej mice and systemic cytokine production was quantified from stimulated lymphocytes harvested four to ten days after feeding. mosquito feeding on c3h/hej mice significantly down regulated ifn gamma production seven to ten days post feeding by cx. pipiens and seven days after ae aegypti feeding. th2 cytokines, il-4 and il-10, were significantly up regulated 4-7 days after cx. pipiens and ae. aegypti feeding. the immunosuppressive effect ...199910081770
[yellow fever]. 199910088360
detection of gb virus c/hepatitis g virus rna by reverse-transcription polymerase chain reaction.recently, a novel rna virus, designated gb virus c or hepatitis g virus (gbv-c/hgv) has been identified which may possibly be associated with human hepatitis. in this study, the nucleotide sequences of the partial nonstructural 5 (ns5) gene of gbv-c/hgv derived from sera of eight chinese patients were determined. the overall degree of nucleotide conservation and the existence of regional highly conserved sequences make this part of the genome suitable for the development of diagnostic reagents. ...199910094376
preliminary studies on the use of solid-phase immunosorbent techniques for the rapid detection of wesselsbron virus (wslv) igm by haemagglutination-inhibition.serum samples from 446 randomly selected persons belonging to different age groups and locations in nigeria were tested for the presence of wslv igm using the flavivirus haemagglutination-inhibition (hi) test adopted to the solid-phase immunosorbent technique (spit). 61 (14%) persons had igm to wslv only, while 9 (2%) persons had heterologous igm to wslv and two other flaviviruses, namely yellow fever and uganda s viruses. there was a high prevalence of igm in people of younger age groups than t ...199910099030
[preparation of single-chained antibodies to surface glycoprotein e from tick-borne encephalitis virus].a single-stranded antibody gene scfv was designed on the base of cdna fragments of genes coding for variable domains of heavy and light chains of mab e6b to tick-borne encephalitis glycoprotein e. high production of stable soluble scfv was reproduced in escherichia coli cells. recombinant antibodies bound to antiidiotypical antibodies to initial mab e6b and to recombinant virus protein e. competitive analysis showed that single-stranded antibodies inhibited reaction between mab e6b and protein e ...199910190234
prevalence of hepatitis g virus rna in human immunodeficiency virus type 1-positive intravenous drug users.the aim of this study was to evaluate the prevalence of the new human flavivirus hepatitis g virus (hgv) in italian intravenous drug users (idus) and its interaction with human immunodeficiency virus type 1 (hiv-1) and hepatitis c virus (hcv).199810195238
in vitro infection of human peripheral blood mononuclear cells by gb virus c/hepatitis g virus c (gbv-c), also known as hepatitis g virus, is a recently discovered flavivirus-like rna agent with unclear pathogenic implications. to investigate whether human peripheral blood mononuclear cells (pbmc) are susceptible to in vitro gbv-c infection, we have incubated pbmc from four healthy blood donors with a human gbv-c rna-positive serum. by means of (i) strand-specific reverse transcription-pcr, cloning, and sequencing; (ii) sucrose ultracentrifugation and rnase sensitivity assays; (i ...199910196301
the clinical significance of simultaneous infection with hepatitis g virus in patients with chronic hepatitis c.hepatitis g virus (hgv) is a recently discovered member of the flavivirus family that has been associated with acute and chronic hepatitis. hgv infection has been reported to coexist in 10-20% of patients with chronic hepatitis c. the significance of simultaneous infection with hgv and hepatitis c virus (hcv) remains to be clarified, as do the effects on hgv of therapeutic interventions such as interferon treatment or liver transplantation. the aims of our study were: 1) to examine the frequency ...199910201473
the 37-amino-acid interdomain of dengue virus ns5 protein contains a functional nls and inhibitory ck2 site.the dengue virus ns5 rna-dependent rna polymerase has been detected in the nucleus of virus-infected mammalian cells. we demonstrate here for the first time using in vitro and in vivo assay systems that the 37-amino-acid linker interdomain of ns5 (residues 369 to 405) contains a nuclear localization sequence (nls) which is capable of targeting b-galactosidase to the nucleus. further, we show that the linker is recognized by subunits of the nls-binding importin complex with an affinity similar to ...199910208852
development and characterization of new flavivirus-resistant mouse strains bearing flv(r)-like and flv(mr) alleles from wild or wild-derived mice.a single genetic locus, flavivirus resistance (flv), controls virus titres and severity of flavivirus infection in mouse brain. it has been mapped to mouse chromosome 5 and shown to include different allelic forms. while the majority of laboratory mouse strains are susceptible to flaviviruses and carry the flv(s) allele, wild mice and laboratory mouse strains recently derived from them are resistant and carry flavivirus-resistance alleles including flv(r)-like and flv(mr) alleles. although there ...199910211958
recombinant, chimaeric live, attenuated vaccine (chimerivax) incorporating the envelope genes of japanese encephalitis (sa14-14-2) virus and the capsid and nonstructural genes of yellow fever (17d) virus is safe, immunogenic and protective in non-human primates.yellow fever 17d virus, a safe and effective live, attenuated vaccine, was used as a vector for genes encoding the protective antigenic determinants of a heterologous member of the genus flavivirus, japanese encephalitis (je) virus, the leading cause of acute viral central nervous system infection and death throughout asia. the viral envelope (prm and e) genes of a full-length cdna clone of yf 17d virus were replaced with the corresponding genes of je sa14-14-2, a strain licensed as a live, atte ...199910217584
identification and analysis of truncated and elongated species of the flavivirus ns1 protein.the flavivirus non-structural glycoprotein ns1 is often detected in western blots as a heterogeneous cluster of bands due to glycosylation variations, precursor-product relationships and/or alternative cleavage sites in the viral polyprotein. in this study, we determined the basis of structural heterogeneity of the ns1 protein of murray valley encephalitis virus (mve) by glycosylation analysis, pulse-chase experiments and terminal amino acid sequencing. inhibition of n-linked glycosylation by tu ...199910225275
genetic interaction of flavivirus nonstructural proteins ns1 and ns4a as a determinant of replicase function.nonstructural protein 1 (ns1) of yellow fever virus (yf) is a glycoprotein localized to extracytoplasmic compartments within infected cells. we have previously shown that ns1 can be supplied in trans and is required for viral rna replication, a process thought to occur in membrane-bound cytoplasmic complexes. here we report that the ns1 gene from a related virus, dengue virus (den), is unable to function in the process of yf rna replication. this virus-specific incompatibility leads to a lack of ...199910233920
nascent flavivirus rna colocalized in situ with double-stranded rna in stable replication complexes.incorporation of bromouridine (bru) into viral rna in kunjin virus-infected vero cells treated with actinomycin d was monitored in situ by immunofluorescence using antibodies reactive with br-rna. the results showed unequivocally that nascent viral rna was located focally in the same subcellular site as dsrna, the putative template for flavivirus rna synthesis. when cells were labeled with bru for 15 min, the estimated cycle period for rna synthesis, the nascent br-rna was not digested in permea ...199910329573
[study of the antigenic structure of tick-borne encephalitis virus using synthetic peptides].a number of peptides, fragments of the envelope protein e of the tick-borne encephalitis virus (sofjin strain), were synthesized. their binding to the polyclonal antiserum to protein e was studied. rats were immunized with both the free peptides and their klh-conjugates, and the resulting antisera were tested for their reactivity toward protein e and for their neutralizing activity toward the virus in cell culture. the only peptide corresponding to the 98-113 sequence of protein e was shown to b ...199810335405
prevalence of gbv c/hgv rna and gbv c/hgv antibodies in french volunteer blood donors: results of a collaborative study.posttransfusion hepatitis still occurs at an incidence of about 1 in 118,000 for hbv and 1 in 220,000 for hcv. this collaborative study aimed to determine the prevalence of a novel flavivirus, gbv-c/hgv, even though its role in transfusion-associated hepatitis is uncertain.199910341332
rapid serologic diagnosis of dengue virus infection using a commercial capture elisa that distinguishes primary and secondary infections.a commercial capture elisa for specific igm and igg antibodies produced during dengue infection (panbio dengue duo) showed excellent sensitivity (99%, n = 78) using sera collected at hospital discharge compared with established elisa and hemagglutination inhibition (hai) assays. furthermore, the elisa was able to diagnose 79% of the dengue cases using sera collected at hospital admission. the elisa also showed high specificity (92%) in paired sera from patients without flavivirus infection (n = ...199910348250
homology model of the dengue 2 virus ns3 protease: putative interactions with both substrate and ns2b cofactor.the crystal structure coordinates of the hepatitis c virus ns3 protease (hcvpro) were used to develop an homology model of the dengue 2 virus ns3 protease (den2pro). the amino acid sequence of den2pro accommodates the same alpha-helices, beta-sheets and protein-binding domains as its hcvpro counterpart, but the model predicts a number of significant differences for den2pro and its interactions with substrates and cofactor. whereas hcvpro contains a zn2+-binding site, there is no equivalent metal ...199910355763
recombinant semliki forest virus particles encoding the prme or ns1 proteins of louping ill virus protect mice from lethal challenge.recombinant semliki forest virus (rsfv) vaccines encoding louping ill virus (liv) genes prme and ns1 were examined. cells transfected with rsfv-prme rna showed correct processing of the precursor prme and the release into the medium of m and e proteins in particulate form, whilst rsfv-ns1-transfected cells secreted glycosylated, heat-labile ns1 dimers. mice immunized with rsfv particles produced antibodies against prme and ns1 that were mainly of the igg2a subtype, indicating that a t-helper 1 i ...199910355766
mutation patterns for two flaviviruses: hepatitis c virus and gb virus c/hepatitis g virus.we studied the mutation patterns of hepatitis c virus (hcv) and gb virus c/hepatitis g virus (hgv). although the mutation patterns of the two viruses were similar to each other, they were quite different from that of hiv. in particular, the similarity of the patterns between hcv or hgv and human nuclear pseudogenes was statistically significant whereas there was no similarity between hiv and human nuclear pseudogenes. this finding suggests that the mutation patterns of hcv and hgv are similar to ...199910359092
the anamnestic neutralizing antibody response is critical for protection of mice from challenge following vaccination with a plasmid encoding the japanese encephalitis virus premembrane and envelope genes.for japanese encephalitis (je), we previously reported that recombinant vaccine-induced protection from disease does not prevent challenge virus replication in mice. moreover, dna vaccines for je can provide protection from high challenge doses in the absence of detectable prechallenge neutralizing antibodies. in the present study, we evaluated the role of postchallenge immune responses in determining the outcome of je virus infection, using mice immunized with a plasmid, pcdna3jeme, encoding th ...199910364301
mapping of functional elements in the stem-anchor region of tick-borne encephalitis virus envelope protein e.envelope protein e of the flavivirus tick-borne encephalitis virus mediates membrane fusion, and the structure of the n-terminal 80% of this 496-amino-acid-long protein has been shown to differ significantly from that of other viral fusion proteins. the structure of the carboxy-terminal 20%, the stem-anchor region, is not known. it contains sequences that are important for membrane anchoring, interactions with prm (the precursor of membrane protein m) during virion assembly, and low-ph-induced s ...199910364309
molecular evidence of mother-to-infant transmission of hepatitis g virus among women without known risk factors for parenteral infections.hepatitis g virus (hgv) rna was detected in 18 of 133 pregnant women from tanzania without known risk factors for hgv infection and in 7 of 18 children born to hgv rna-positive mothers. molecular evidence of mother-to-infant transmission was obtained only for three of seven children. hgv rna was also detected in 4 of 42 children born to non-hgv-infected women. thus, mechanisms other than materno-filial may play an important role in hgv transmission during early childhood.199910364608
degradation of japanese encephalitis virus by neutrophils.the ability of neutrophils to degrade the phagocytosed japanese encephalitis (je) virion, via triggering of the respiratory burst and generation of toxic radicals has been investigated. jev or jev-induced macrophage derived factor (mdf) induces increase in intracellular oxidative signals with generation of superoxide anion (o2-), via activation of cytosolic nadph and subsequent formation of hydrogen peroxide, with maximum activity on day 7 post infection. the response was sensitive to anti-mdf a ...199910365083
partial nucleotide sequencing of the ns3/helicase region of hepatitis g virus to prove vertical study non-parental transmission of hepatitis g virus and/or gb virus c (hgv/gbv-c), we sequenced and compared the ns3/helicase region of the virus for five hgv/gbv-c rna-positive mothers and their 11 children who had experienced neither blood transfusion nor overt hepatitis and were negative for hbv, hcv and hiv, except in one mother coinfected with hcv. the nucleotide sequences of the familial hgv/gbv-c isolates showed high similarity of 99-100% (mean 99.8%, 100% at the deduced amino acid le ...199910386379
crystallization, characterization and measurement of mad data on crystals of dengue virus ns3 serine protease complexed with mung-bean bowman-birk inhibitor.crystallization and preliminary characterization of the essential dengue virus ns3 serine protease complexed with a bowman-birk-type inhibitor from mung beans are reported. as the structure proved resistant to solution by molecular replacement and multiple isomorphous replacement methods, multi-wavelength anomalous diffraction data at the liii edge of a holmium derivative have been measured. promising bijvoet and dispersive signals which are largely consistent with expected values have been extr ...199910393310
membrane permeabilization by small hydrophobic nonstructural proteins of japanese encephalitis virus.infection with japanese encephalitis virus (jev), a mosquito-borne flavivirus, may cause acute encephalitis in humans and induce severe cytopathic effects in various types of cultured cells. we observed that jev replication rendered infected baby hamster kidney (bhk-21) cells sensitive to the translational inhibitor hygromycin b or alpha-sarcine, to which mock-infected cells were insensitive. however, little is known about whether any jev nonstructural (ns) proteins contribute to virus-induced c ...199910400716
functional analysis of cell surface-expressed hepatitis c virus e2 glycoprotein.hepatitis c virus (hcv) glycoproteins e1 and e2, when expressed in eukaryotic cells, are retained in the endoplasmic reticulum (er). c-terminal truncation of e2 at residue 661 or 715 (position on the polyprotein) leads to secretion, consistent with deletion of a proposed hydrophobic transmembrane anchor sequence. we demonstrate cell surface expression of a chimeric glycoprotein consisting of e2 residues 384 to 661 fused to the transmembrane and cytoplasmic domains of influenza a virus hemaggluti ...199910400776
a monoclonal antibody that recognizes the predicted tick-borne encephalitis virus e protein fusion sequence blocks fusion.the fusion motif of tick-borne encephalitis virus e protein has been predicted to be located within its conserved region (98-120). results are presented to demonstrate that non-neutralizing monoclonal antibody which recognizes a synthetic peptide corresponding to residues 98-113 of the e protein sequence can block the fusion of the virus particles with artificial membranes.199910416385
communicable diseases surveillance. you left an error in the record. 199910432763
antigenic relatedness of selected flaviviruses: study with homologous and heterologous immune mouse ascitic fluids.the antigenic relationship of 9 flaviviruses, yellow fever (yf), wesselsbron (wsl), uganda s (ugs), potiskum (pot), west nile (wn), banzi (ban), zika (zk), dengue type 1 (den-1) and dengue type 2 (den-2), was assessed by cross-haemagglutination-inhibition (cross-hi) and cross-complement fixation (cross-cf) reactions between each of the viruses and their homologous immune mouse ascitic fluids. titre ratios were calculated using the heterologous and homologous titres. cross-cf reactions revealed w ...199810436653
mosquito-borne viruses in western europe: a review.several mosquito-borne arboviruses belonging to the genera alphavirus, flavivirus, and bunyavirus have been reported to occur in mosquitoes and to infect humans and other vertebrates in western europe. these zoonotic viruses circulate in nature either in an aedes-mammal, anopheles-mammal, or culex-bird transmission cycle. infected humans normally do not contribute to the virus circulation. west nile virus (flavivirus) caused an outbreak of fever, malaise, pain in eyes and muscles, and headache a ...199910436876
response to je vaccine among hiv-infected children, bangkok, thailand.since 1990, japanese encephalitis (je) vaccine has been part of epi in northern thailand, where there is a high prevalence of je and hiv infection. to evaluate the immunogenicity and safety of je vaccine among hiv-infected children, we conducted a retrospective study of hiv-infected and uninfected children who received 2 doses of je vaccine at 12 months of age. pre- and post-immunization plasma specimens were tested by plaque reduction neutralization for antibody levels to je and dengue(1-4) vir ...199810437937
molecular characterization of the 5' non-coding region of south african gbv-c/hgv isolates: major deletion and evidence for a fourth virus c/hepatitis g virus (gbv-c/hgv) has been characterised as a novel flavivirus, and to date three known genotypes have been cloned. greater genetic variation of gbv-c/hgv has been demonstrated in west african isolates, but no major deletions have been shown in the 5' non-coding region (ncr). the 5'ncr regulates protein translation via an internal ribosomal entry site (ires). we cloned, sequenced, and analysed a 344-bp polymerase chain reaction (pcr) product, representing >60% of the 5'ncr ...199910440808
prediction of three-dimensional structure and mapping of conformational epitopes of envelope glycoprotein of japanese encephalitis virus.japanese encephalitis virus (jev), a mosquito-borne flavivirus, is an important human pathogen. the envelope glycoprotein (egp), a major structural antigen, is responsible for viral haemagglutination and eliciting neutralising antibodies. the three-dimensional structure of the egp of jev was predicted using the knowledge-based homology modeling approach and x-ray structure data of the egp of tick-borne encephalitis virus as a template (rey et al., 1995). in the initial stages of optimisation, a ...199910441554
partial agonist effect influences the ctl response to a heterologous dengue virus serotype.activation of dengue serotype-cross-reactive memory ctl during secondary dengue virus (dv) infection is thought to be important in the pathogenesis of dengue hemorrhagic fever. to model this effect, we studied the ctl responses to dv types 2 (d2v) and 3 (d3v) in pbmc from an individual previously infected with d3v. dv-specific cd8+ ctl from this donor recognized two hla-b62-restricted epitopes on the ns3 protein, aa 71-79 (svkkdlisy) and 235-243 (amkglpiry). both d3v-specific and d2v/d3v-cross-r ...199910453018
a focus of deer tick virus transmission in the northcentral united states.we screened salivary glands from adult deer ticks collected near spooner and hayward, wisconsin, to determine whether deer tick virus, a recently described flavivirus, occurs with other tickborne agents in the upper midwest. intraacinar inclusions suggestive of replicating virus were detected in 4 (4.6%) of 87 ticks. the virus was isolated by suckling-mouse inoculation.199910460180
fatal dengue hemorrhagic fever in cuba, 1997.after more than 15 years without dengue activity, a dengue ii epidemic was reported in cuba in 1997. three thousand and twelve serologically confirmed cases were reported, with 205 dengue hemorrhagic fever/dengue shock syndrome (dhf/dss) cases and 12 fatalities. this report presents the clinical, serologic, and virologic findings in the 12 fatal dhf/dss cases.199910460923
identification of genetic variation among st. louis encephalitis virus isolates, using single-strand conformation polymorphism analysis.a single-strand conformation polymorphism (sscp) technique was developed for identification of genetic variation among 26 isolates of st. louis encephalitis (sle) virus. a 750-bp portion of the envelope gene was amplified by reverse transcription-polymerase chain reaction (rt-pcr) and the products analyzed by sscp. sscp reliably identified genetic variation among the isolates from the us, central and south america. closely related isolates from a smaller geographic area (panama) were also distin ...199910471026
synthesis of new photocross-linking 5-c-base-substituted utp analogs and their application in highly selective affinity labelling of the tick-borne encephalitis virus rna replicase proteins.a new photocross-linking 5-c-base-substituted utp analogs, carrying 4-azidoperfluorobenzoyl and 4-azidoaniline residues were synthesized. two flavivirus proteins ns5 and ns3 are shown to be labelled after rna synthesis in the presence of the analogs, irradiation (lambda > 300 nm) and subsequent [alpha-32p]ntp incorporation.199910474230
unlicensed vaccines and bioweapon defense in world war ii. 199910478686
mutagenesis of the ns2b-ns3-mediated cleavage site in the flavivirus capsid protein demonstrates a requirement for coordinated processing.analysis of flavivirus polyprotein processing has revealed the presence of a substrate for the virus-encoded ns2b-ns3 protease at the carboxy-terminal end of the c (capsid or core) protein. cleavage at this site has been implicated in the efficient generation of the amino terminus of prm via signal peptidase cleavage. yellow fever virus has four basic residues (arg-lys-arg-arg) in the p1 through p4 positions of this cleavage site. multiple alanine substitutions were made for these residues in or ...199910482557
[tick-encephalitis after a vacation in southern germany].a 38-year-old man was admitted with signs of meningoencephalitis. tick-borne encephalitis was considered because the patient reported a tick bite during a vacation in south germany and because of the biphasic course of the symptoms. serology for tick-borne encephalitis was positive: this constituted the first reported positive serology outcome in the national institute for public health and environment in the netherlands. tick-borne encephalitis is an infection with a flavivirus transmitted by a ...199910494331
nucleoside triphosphatase and rna helicase activities associated with gb virus b nonstructural protein virus b (gbv-b) is a positive-stranded rna virus that belongs to the flaviviridae family. this virus is closely related to hepatitis c virus (hcv) and causes acute hepatitis in tamarins (saguinus species). nonstructural protein 3 (ns3) of gbv-b contains sequence motifs predictive of three enzymatic activities: serine protease, nucleoside triphosphatase (ntpase), and rna helicase. the n-terminal serine protease has been characterized and shown to share similar substrate specificity with the hc ...199910497107
molecular and biological changes associated with hela cell attenuation of wild-type yellow fever virus.six passages of the mosquito-borne flavivirus yellow fever (yf) wild-type strain asibi in hela cells attenuated the virus for monkeys and newborn mice and resulted in loss of mosquito competence. attenuation after the passage in hela cells was not unique to yf virus strain asibi as demonstrated by the hela passage attenuation of wild-type yf virus strain french viscerotropic virus and yf vaccine virus 17d-204 for newborn mice. in contrast, wild-type strain dakar 1279 and the french neurotropic v ...199910497116
trans-complementation analysis of the flavivirus kunjin ns5 gene reveals an essential role for translation of its n-terminal half in rna replication.recently we described rescue of defective kunjin virus (kun) rnas with small deletions in the methyltransferase and rna polymerase motifs of the ns5 gene, using bhk cells stably expressing kun replicon rna (repbhk cells) as helper (a. a. khromykh et al., j. virol. 72:7270-7279, 1998). we have now extended our previous observations and report successful trans-complementation of defective kun rnas with most of the ns5 gene deleted or substituted with a heterologous (dengue virus) ns5 sequence. rep ...199910516033
markers for trans-golgi membranes and the intermediate compartment localize to induced membranes with distinct replication functions in flavivirus-infected cells.replication of the flavivirus kunjin virus is associated with virus-induced membrane structures within the cytoplasm of infected cells; these membranes appear as packets of vesicles associated with the sites of viral rna synthesis and as convoluted membranes (cm) and paracrystalline arrays (pc) containing the components of the virus-specified protease (e. g. westaway, j. m. mackenzie, m. t. kenney, m. k. jones, and a. a. khromykh, j. virol. 71:6650-6661, 1997). to determine the cellular origins ...199910516064
biological consequences of deletions within the 3'-untranslated region of flaviviruses may be due to rearrangements of rna secondary was previously reported that deletions introduced into the 3'-untranslated region (3'-utr) of dengue type 4 (den 4) virus (men, r., bray, m., clark, d., chanock, r.m., lai, c.j., 1996. den 4 virus mutants containing deletions in the 3'-noncoding region of the rna genome: analysis of growth restriction in cell culture and altered viremia pattern and immunogenicity in rhesus monkeys. j. virol. 70, 3930-3937), tick-borne encephalitis (tbe) virus (mandl, c.w., holzmann, h., meixner, t., rauscher, ...199910518708
Displaying items 1101 - 1200 of 3318