Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| chemical mutagenesis of dengue virus type 4 yields mutant viruses which are temperature sensitive in vero cells or human liver cells and attenuated in mice. | a recombinant live attenuated dengue virus type 4 (den4) vaccine candidate, 2adelta30, was found previously to be generally well tolerated in humans, but a rash and an elevation of liver enzymes in the serum occurred in some vaccinees. 2adelta30, a non-temperature-sensitive (non-ts) virus, contains a 30-nucleotide deletion (delta30) in the 3' untranslated region (utr) of the viral genome. in the present study, chemical mutagenesis of den4 was utilized to generate attenuating mutations which may ... | 2001 | 11559806 |
| expression and purification of dengue virus type 2 envelope protein as a fusion with hepatitis b surface antigen in pichia pastoris. | the methylotrophic yeast, pichia pastoris, has been used as a host to express the envelope protein (den2e) of dengue type 2 virus (ngc strain) as a chimera with hepatitis b surface antigen (hbsag): a protein known to self assemble into virus-like particles (vlps) and to be efficiently expressed in p. pastoris. the den2e gene used in this study is a truncated version encoding the first 395 amino acid (aa) residues of the mature den2e protein; the hbsag gene encodes the full length 226 aa hbsag pr ... | 2001 | 11570849 |
| development of dengue virus type 2 replicons capable of prolonged expression in host cells. | as part of a program to develop a dengue virus vaccine which avoids the deleterious effects of antibody dependent enhancement (ade) of infection mediated by antibodies to dengue virus structural proteins, we have begun to investigate the possibility of designing dengue vaccines based on non-structural proteins. | 2001 | 11580862 |
| activity of recombinant dengue 2 virus ns3 protease in the presence of a truncated ns2b co-factor, small peptide substrates, and inhibitors. | recombinant forms of the dengue 2 virus ns3 protease linked to a 40-residue co-factor, corresponding to part of ns2b, have been expressed in escherichia coli and shown to be active against para-nitroanilide substrates comprising the p6-p1 residues of four substrate cleavage sequences. the enzyme is inactive alone or after the addition of a putative 13-residue co-factor peptide but is active when fused to the 40-residue co-factor, by either a cleavable or a noncleavable glycine linker. the ns4b/n ... | 2001 | 11581268 |
| synergistic neutralizing antibody response to a dengue virus type 2 dna vaccine by incorporation of lysosome-associated membrane protein sequences and use of plasmid expressing gm-csf. | we have previously shown that a dengue virus type 1 dna vaccine expressing premembrane (prm) and envelope (e) genes was immunogenic in mice and monkeys and that rhesus monkeys vaccinated with this construct were completely to partially protected from virus challenge. in order to improve the immunogenicity of dengue dna vaccines, we have evaluated the effect of lysosome targeting of antigens and coimmunization with a plasmid expressing gm-csf on antibody responses. a dengue virus type 2 candidate ... | 2001 | 11883007 |
| vertical transmission of dengue-2 virus through aedes albopictus mosquitoes. | 2001 | 12206042 | |
| construction of infectious dengue 2 virus cdna clones using high copy number plasmid. | procedures for cloning entire dengue serotype 2 virus genome in the multiple cloning site of a commercially available high copy number plasmid are described. the 10.7 kb viral rna genome was reverse transcribed, amplified as three overlapping dna fragments and successively ligated into pbluescript ii ks, which contains the cole1 origin of replication. when propagated at room temperature (20-25 degrees c) under low level of antibiotic selection, the full-length recombinant plasmid was stable upon ... | 2001 | 11164920 |
| antibody-dependent enhancement of heterotypic dengue infections involved in suppression of ifngamma production. | antibody-dependent enhancement has been implicated in some outbreaks of epidemic dengue hemorrhagic fever, however, the mechanism of antibody-dependent enhancement is not well known. this study was conducted to investigate the cross-protection and cross-enhancement of dengue-2 virus infections by dengue-1 immune sera. it was found that dengue-1 immune sera at 1:5 dilution (n = 12) could neutralize dengue-2 infections in bhk-21 cells, as assessed by a standard plaque-reduction neutralization assa ... | 2001 | 11170052 |
| a model of the real-time correlation of viral titers with immune reactions in antibody-dependent enhancement of dengue-2 infections. | we simultaneously assessed dengue-2 virus (den-2) titers by real-time quantitative reverse transcription-polymerase chain reaction (rt-pcr) and immune reactions including interleukin-4 (il-4), interferon-gamma (ifn-gamma) and prostaglandin e(2) (pge(2)) production by human mononuclear cells (mnls) in a model of antibody-dependent enhancement (ade). we found that den-1 immune sera at 1:100 and 1:250, but not those at 1:10 or control sera, enhanced den-2 infections in human mnls as assessed by the ... | 2001 | 11172984 |
| electron microscopic study of persistent dengue virus infection: analysis using a cell line persistently infected with dengue-2 virus. | we investigated persistent infection of epstein-barr virus (ebv)-transformed lymphoblastoid cells with dengue virus using a transmission electron microscope. most of the infected cells kept an intact morphology with only a few virus particles in the cytoplasm, but without any indication of active viral replication. some cells were apoptotic and a few dengue virus particles were present in these apoptotic cells. raji cells acutely infected with dengue-2 virus showed degenerative morphology. there ... | 2001 | 11223720 |
| [clinical features of dengue fever in children during the outbreak in santiago de cuba]. | a study of the dengue outbreak occurred from january to november 1997 in santiago de cuba municipality was performed to characterize the clinical picture of the patients. the sample was taken from those patients presenting with clinical and epidemiological elements and positive igm determination serological test. seventy-seven patients were confirmed as having dengue virus 2 infection whose clinical-humoral characteristic was dengue fever predominantly present in school boys. the clinical pictur ... | 2001 | 11826532 |
| identification of epitopes on the envelope (e) protein of dengue 2 and dengue 3 viruses using monoclonal antibodies. | of a panel of forty-six anti-dengue 3 monoclonal antibodies (mabs) only three neutralised infection of bhk cells by dengue 3 virus. attempts to select neutralisation escape mutants (n.e.m.) with two of these antibodies failed. the n.e.m. population selected in the presence of the third neutralising antibody, 1h9, had a nucleotide change at position 1157 of the e protein gene resulting in a non-conservative amino acid change at e386 for a lys to an asn. a dengue 2 n.e.m. was selected with the fla ... | 2001 | 11811694 |
| [studies of the resistance of the recombinant alphavirus rnas containing dengue-2 prm gene to virus infection]. | the amplified prm gene of dengue-2 virus was cloned into the downstream sp6 promoter-psfv vector and the recombinant plasmid (psf.rm2) dna which contained sense- or antisense-prm gene, was selected. psf.rm2 dna and helper dna linearized by the enzyme spei digestion were both transcribed in vitro into recombinant rnas which contained the capping analog on the 5'-end and contaansfected into bhk cells by electroportation. the the transfected host cells were challenged with dengue-2 virus and the re ... | 2001 | 12549088 |
| differential susceptibility of aedes aegypti to infection by the american and southeast asian genotypes of dengue type 2 virus. | outbreaks of dengue hemorrhagic fever have coincided with the introduction of the southeast (se) asian genotype of dengue type 2 virus in the western hemisphere. this introduced genotype appears to be rapidly displacing the indigenous, american genotype of dengue 2 virus throughout the region. these field observations raise the possibility that the se asian genotype of dengue 2 is better adapted for vector transmission than its american counterpart. to evaluate this hypothesis, we compared the a ... | 2001 | 12680353 |
| chimeric dengue type 2/type 1 viruses induce immune responses in cynomolgus monkeys. | chimeric dengue type 2/type 1 (den2/1) viruses, which contain the structural genes of the dengue-1 (16007) parental virus and the nonstructural genes of the den2-pdk53 virus, have been constructed. these den2/1 viruses induce high levels of den1 virus-specific neutralizing antibodies in mice. in this study, the den2/1 viruses induced den1 virus-specific neutralizing antibodies without the development of viremia in cynomolgus monkeys. dengue virus-specific igm antibodies were detected in the sera ... | 2002 | 12693596 |
| [changes in element content in aedes albopictus infected by dengue virus type ii]. | to study the changes in the content of elements in aedes albopictus after dengue virus type ii (dv2) infection. | 2002 | 12567999 |
| heparan sulfate-mediated binding of infectious dengue virus type 2 and yellow fever virus. | dengue virus type 2 and yellow fever virus are arthropod-borne flaviviruses causing hemorrhagic fever in humans. identification of virus receptors is important in understanding flavivirus pathogenesis. the aim of this work was to study the role of cellular heparan sulfate in the adsorption of infectious yellow fever and dengue type 2 viruses. virus attachment was assessed by adsorbing virus to cells, washing unbound virus away, releasing cell-bound virus by freezing/thawing, and then titrating t ... | 2002 | 11878919 |
| rna silencing of dengue virus type 2 replication in transformed c6/36 mosquito cells transcribing an inverted-repeat rna derived from the virus genome. | double-stranded rna (dsrna) initiates cellular posttranscriptional responses that are collectively called rna silencing in a number of different organisms, including plants, nematodes, and fruit flies. in plants, rna silencing has been associated with protection from virus infection. in this study, we demonstrate that dsrna-mediated interference also can act as a viral defense mechanism in mosquito cells. c6/36 (aedes albopictus) cells were stably transformed with a plasmid designed to transcrib ... | 2002 | 12438618 |
| detection of dengue virus replication in peripheral blood mononuclear cells from dengue virus type 2-infected patients by a reverse transcription-real-time pcr assay. | while dengue virus is thought to replicate in mononuclear phagocytic cells in vivo, attempts to detect it in peripheral blood mononuclear cells (pbmc) by virus isolation or antigen detection have had variable and generally low rates. in this study, we developed a reverse transcription (rt)-real-time pcr assay to quantify positive- and negative-sense rna of dengue virus type 2 within the cells. the assay includes an rt step using either sense or antisense primer followed by a real-time pcr step u ... | 2002 | 12454138 |
| complete nucleotide sequence analysis of a brazilian dengue virus type 2 strain. | in the last decade, dengue fever (df) in brazil has been recognized as an important public health problem, and an increasing number of dengue haemorrhagic fever (dhf) cases have been reported since the introduction of dengue virus type 2 (den-2) into the country in 1990. in order to analyze the complete genome sequence of a den-2 brazilian strain (br64022/98), we designed primers to amplify contiguous segments of approximately 500 base pairs across the entire sequence of the viral genome. twenty ... | 2002 | 12471426 |
| geographic genetic variation in populations of the dengue virus vector aedes aegypti. | isoenzyme variation was assessed in 79 mosquito samples of aedes aegypti, and susceptibility to a dengue 2 virus strain was evaluated in 83 samples. analysis of fst values, differentiation indexes, and geographic distances separating populations revealed that genetic differences between populations depended on the species' history of migration and colonization. three major clusters were identified: (1). the sylvan form, ae. ae. formosus, from west africa and some islands in the indian ocean; (2) ... | 2002 | 12486524 |
| serological & virological investigation of an outbreak of dengue fever in gwalior, india. | an outbreak of febrile illness occurred between september to november 2001 in gwalior, madhya pradesh affecting individuals mostly in the age group < 30 yr. a total of 312 febrile indoor patients suspected to have dengue infection were investigated. | 2002 | 12807151 |
| novel dl-galactan hybrids from the red seaweed gymnogongrus torulosus are potent inhibitors of herpes simplex virus and dengue virus. | a novel series of dl-galactan hybrids extracted from the red seaweed gymnogongrus torulosus, was evaluated for its in vitro antiviral properties against herpes simplex virus type 2 (hsv-2) and dengue virus 2 (den-2). these compounds were very active against both viruses with inhibitory concentration 50% (ic50) values in the range 0.6-16 microg/ml for hsv-2 and 0.19-1.7 microg/ml for den-2, respectively, as determined in a virus plaque reduction assay in vero cells. the dl-galactans lacked of cyt ... | 2002 | 12238532 |
| recombinant dengue virus type 2 envelope/hepatitis b surface antigen hybrid protein expressed in pichia pastoris can function as a bivalent immunogen. | a truncated version of the dengue virus type 2 envelope protein (den2e) encoding the first 395 amino acid (aa) residues, and den2e fused in-frame with the full-length 226-aa hepatitis b surface antigen (den2e-hbsag) protein were expressed in the methylotrophic yeast, pichia pastoris. both the recombinant proteins showed evidence of the capacity to form high molecular weight aggregates. electron microscopic analysis of the purified proteins showed that while den2e displayed an amorphous morpholog ... | 2002 | 12270598 |
| in vitro determination of dengue virus type 2 ns2b-ns3 protease activity with fluorescent peptide substrates. | the ns2b-ns3(pro) polyprotein segment from the dengue virus serotype 2 strain 16681 was purified from overexpressing e. coli by metal chelate affinity chromatography and gel filtration. enzymatic activity of the refolded ns2b-ns3(pro) protease complex was determined in vitro with dansyl-labeled peptide substrates, based upon native dengue virus type 2 cleavage sites. the 12mer substrate peptides and the cleavage products could be separated by reversed-phase hplc, and were identified by uv and fl ... | 2002 | 12297031 |
| heparin inhibits dengue-2 virus infection of five human liver cell lines. | liver is suggested to be the major target of dengue virus infection and plays an important role in the immunopathogenesis of dengue hemorrhagic fever. previously, we reported that five human liver cell lines (huh-7, ha22t, hep3b, plc, and chang liver) with various degrees of differentiation and tumorigenicity showed different susceptibility for dengue virus infection. here, we demonstrate that heparin, an analogue of heparan sulfate (hs), can compete with hs on cell membrane for virus binding an ... | 2002 | 12323403 |
| high circulating levels of the dengue virus nonstructural protein ns1 early in dengue illness correlate with the development of dengue hemorrhagic fever. | infection with any 1 of 4 dengue viruses produces a spectrum of clinical illness ranging from a mild undifferentiated febrile illness to dengue fever (df) to dengue hemorrhagic fever (dhf), a potentially life-threatening disease. the morbidity and mortality of dhf can be reduced by early hospitalization and careful supportive care. to determine its usefulness as a predictor of dhf, plasma levels of the secreted dengue virus nonstructural protein ns1 (sns1) were measured daily in 32 children with ... | 2002 | 12355369 |
| genetic structure of aedes aegypti populations in chiang mai (thailand) and relation with dengue transmission. | we analysed the population genetic structure and differentiation regarding vector competence for a dengue virus of 15 aedes aegypti samples collected from chiang mai in northern thailand. based on polymorphism of 10 isoenzyme loci, genetic differentiation was confirmed among samples collected in different subdistricts (high fst values and p < 0.05). based on infection rate for a dengue 2 virus, susceptibilities were similar in mosquitoes collected in san nuea subdistrict and in choeng doi subdis ... | 2002 | 12358622 |
| variation in vector competence for dengue 2 virus among 24 collections of aedes aegypti from mexico and the united states. | aedes aegypti from 24 collections in mexico and the united states were challenged orally with dengue 2 virus jam1409 (den-2 jam1409). the vector competence (vc) of the populations ranged from 24% to 83%. mosquito populations from the yucatan exhibited greater vc than those from other areas of mexico. the presence or absence of a midgut infection barrier (mib) and a midgut escape barrier (meb) was determined for mosquitoes in each population. the percentage of mosquitoes exhibiting an mib ranged ... | 2002 | 12363070 |
| increased production of interleukin-8 in primary human monocytes and in human epithelial and endothelial cell lines after dengue virus challenge. | the more severe form of dengue virus infection, dengue hemorrhagic fever, is characterized by plasma leakage and derangements in hemostasis. as elevated interleukin-8 (il-8) levels have been observed in sera from patients with more severe disease manifestations, a study was initiated to look at the effect of dengue virus infection in vitro on proinflammatory cytokine secretion and expression. a significant increase in il-8 levels in the culture supernatant of primary human monocytes infected wit ... | 2002 | 11991987 |
| an rna cap (nucleoside-2'-o-)-methyltransferase in the flavivirus rna polymerase ns5: crystal structure and functional characterization. | viruses represent an attractive system with which to study the molecular basis of mrna capping and its relation to the rna transcription machinery. the rna-dependent rna polymerase ns5 of flaviviruses presents a characteristic motif of s-adenosyl-l-methionine-dependent methyltransferases at its n-terminus, and polymerase motifs at its c-terminus. the crystal structure of an n-terminal fragment of dengue virus type 2 ns5 is reported at 2.4 a resolution. we show that this ns5 domain includes a typ ... | 2002 | 12032088 |
| temporal genetic variation in aedes aegypti populations in ho chi minh city (vietnam). | aedes aegypti, the main vector of dengue viruses in asia, displays variation in population density over time. the larval habitats of this species being unevenly distributed and transient (depending on cycles of drought and flood), the forces generating temporal variation in gene frequencies in populations are studied. we sampled seven mosquito populations from ho chi minh city (vietnam) and its suburbs on five occasions between april 1999 and august 2000. we investigated genetic variation by stu ... | 2002 | 12080364 |
| phylogenetic relationships and differential selection pressures among genotypes of dengue-2 virus. | to elucidate the processes controlling the emergence and spread of dengue-2 virus (den-2) we examined the evolution of viral isolates sampled from both local (viet nam) and global populations. our phylogenetic analysis, incorporating envelope (e) glycoprotein sequences from 147 isolates of den-2, provided a more complete picture of viral diversity, with a newly defined "cosmopolitan" genotype having a near global distribution and two other genotypes restricted to asia. by analyzing rates of syno ... | 2002 | 12093174 |
| endothelial cell apoptosis induced by antibodies against dengue virus nonstructural protein 1 via production of nitric oxide. | the onset of vascular leakage and hemorrhagic diathesis is one of the life-threatening complications occurring in dengue patients, yet the pathogenic mechanisms are not well understood. in this study, we demonstrated that abs against dengue virus nonstructural protein 1 (ns1) generated in mice cross-reacted with human endothelial cells and mouse vessel endothelium. after binding, mouse anti-ns1 abs induced endothelial cell apoptosis in a caspase-dependent manner. inducible no synthase expression ... | 2002 | 12097367 |
| dengue virus selectively induces human mast cell chemokine production. | severe dengue virus infections usually occur in individuals who have preexisting anti-dengue virus antibodies. mast cells are known to play an important role in host defense against several pathogens, but their role in viral infection has not yet been elucidated. the effects of dengue virus infection on the production of chemokines by human mast cells were examined. elevated levels of secreted rantes, mip-1alpha, and mip-1beta, but not il-8 or ena-78, were observed following infection of ku812 o ... | 2002 | 12134044 |
| zinc accelerates dengue virus type 2-induced apoptosis in vero cells. | dengue virus type 2 (denv-2) infection induced apoptotic cellular dna fragmentation in vero cells within 8 days of infection. the addition of high concentrations of extracellular zn(2+) but not ca(2+), mg(2+) or mn(2+) to the cell culture medium hastened the detection of apoptosis to within 4 h after infection. no apoptotic cellular dna fragmentation was detected in the cell culture treated with zn(2+) alone or infected with heat- or ultraviolet light-inactivated denv-2 in the presence of zn(2+) ... | 2002 | 12135735 |
| effect of dengue-1 antibodies on american dengue-2 viral infection and dengue haemorrhagic fever. | in iquitos, peru, no cases of dengue haemorrhagic fever have been recorded in individuals infected with dengue-1 virus followed by american genotype dengue-2 (american dengue-2) virus. we assayed serum samples collected in iquitos that tested positive for antibodies of monotype dengue-1 and monotype dengue-2 using a plaque reduction neutralisation test to determine their ability to neutralise the infectivity of two dengue-1 viruses, two american dengue-2 viruses, and two asian dengue-2 viruses. ... | 2002 | 12147378 |
| platelet adhesion to dengue-2 virus-infected endothelial cells. | platelets in circulation normally do not adhere to resting endothelial cells. however, in response to vascular injury they adhere to stimulated endothelium and thereby play an essential role in hemostasis and thrombosis. infection with dengue-2 virus can cause illness accompanied by thrombocytopenia and hemorrhage. increased adherence of platelets to stimulated endothelial cells could contribute to the thrombocytopenia. in this study, adherence of radioisotopically labeled platelets to 1) unstim ... | 2002 | 12164302 |
| expression, purification, and characterization of the rna 5'-triphosphatase activity of dengue virus type 2 nonstructural protein 3. | dengue virus type 2 (den2), a member of the flaviviridae family of positive-strand rna viruses, contains a single rna genome having a type i cap structure at the 5' end. the viral rna is translated to produce a single polyprotein precursor that is processed to yield three virion proteins and at least seven nonstructural proteins (ns) in the infected host. ns3 is a multifunctional protein having a serine protease catalytic triad within the n-terminal 180 amino acid residues which requires ns2b as ... | 2002 | 12167347 |
| isolation of dengue 2 virus from a patient with central nervous system involvement (transverse myelitis). | a dengue fever case is described in a 58-year-old male patient with febrile illness and thrombocytopenia complicated by neurological involvement characterized by transverse myelitis followed by weakness of both legs and flaccid paralysis. muscle strength was much diminished and bilateral areflexia was observed. dengue 2 (den-2) virus was isolated and the patient sero-converted by hemagglutination-inhibition and igm-elisa tests. the rt-pcr test was positive to den-2 in acute phase serum and cultu ... | 2002 | 12170337 |
| production of the baculovirus-expressed dengue virus glycoprotein ns1 can be improved dramatically with optimised regimes for fed-batch cultures and the addition of the insect moulting hormone, 20-hydroxyecdysone. | a perennial problem in recombinant protein expression is low yield of the product of interest. a strategy which has been shown to increase the production of baculovirus-expressed proteins is to utilise fed-batch cultures. one disadvantage of this approach is the time-consuming task of optimising the feeding strategy. previously, a statistical optimisation routine was applied to develop a feeding strategy that increased the yield of beta-galactosidase (beta-gal) by 2.4-fold (biotechnol. bioeng. 5 ... | 2002 | 12176145 |
| inhibitory potential of neem (azadirachta indica juss) leaves on dengue virus type-2 replication. | in the present study we report in vitro and in vivo inhibitory potential of crude aqueous extract of neem leaves and pure neem compound (azadirachtin) on the replication of dengue virus type-2. in vitro antiviral activity of aqueous neem leaves extract assessed in c(6/36) (cloned cells of larvae of aedes albopictus) cells employing virus inhibition assay showed inhibition in dose dependent manner. the aqueous extract of neem leaves at its maximum non-toxic concentration of 1.897 mg/ml completely ... | 2002 | 11801392 |
| dengue type 2 virus subviral extracellular particles produced by a stably transfected mammalian cell line and their evaluation for a subunit vaccine. | a dengue subunit vaccine candidate was developed using a mammalian cell line continuously expressing subviral extracellular particles (eps) of the new guinea c (ngc) strain of dengue type 2 virus. the cell line, designated d cell line, maintained envelope (e) antigen production for at least 10 passages. the eps contained an e protein biochemically and antigenically equivalent to authentic e produced by ngc-infected vero cells. two immunizations of balb/c mice with purified eps containing 100ng o ... | 2002 | 11803066 |
| [aedes aegypti, vector of the dengue virus: spatio-temporal structure of its genetic variation]. | aedes aegypti is the main vector of dengue viruses. methods for limiting the spread of dengue outbreaks are currently based on vector control. estimates of population genetic organization and gene flow with respect to vector capacity have provided great insights into dengue epidemiology. in vietnam, dengue hemorrhagic fever was detected in the 1950's and becomes today the major problem of public health. among factors influencing dengue epidemiology, ecological disturbances have a direct impact o ... | 2002 | 12669664 |
| dengue fever outbreaks in two villages of dharmapuri district in tamil nadu. | dengue fever is an important public health problem in india. in recent years this disease has extended to rural areas also due to rapid urbanization. in tamil nadu, fever outbreaks were reported in two villages of dharmapuri district during may and september 2001 with clinical symptoms suggestive of dengue fever. epidemiological, virological and entomological investigations were carried out in these two villages to ascertain the etiology of the outbreaks. | 2002 | 12674826 |
| antigenic cell associated dengue 2 virus proteins detected in vitro using dengue fever patients sera. | at least three major antigenic dengue 2 virus proteins were recognized by pooled dengue fever patients' sera in infected aedes albopictus (c6/36) mosquito cells. dengue virus envelope (e), premembrane (prm) and non-structural protein 1 (ns 1) dimer were detected beginning on day 3 postinfection in both the cell membrane and cytosolic fractions. using the patients' sera, the presence of antigenic intermediate core protein (c)-prm and ns1-non-structural protein 2a (ns2a) in the cytoplasmic fractio ... | 2002 | 16329553 |
| variation over space and time of aedes aegypti in phnom penh (cambodia): genetic structure and oral susceptibility to a dengue virus. | we studied spatial and temporal variation in 20-23 aedes aegypti samples collected in phnom penh and its suburbs to estimate the population genetic structure using allozymes and the susceptibility to a dengue-2 virus. based on seven allozyme systems, we detected low levels of genetic exchanges (i.e. high, significant f(st) values) between populations collected in the city centre, and different patterns of genetic structure for samples collected in the suburbs, depending on the type of environmen ... | 2003 | 15134196 |
| antibodies from dengue patient sera cross-react with endothelial cells and induce damage. | dengue virus infection causes a wide range of diseases from the mild febrile illness dengue fever to the life-threatening dengue hemorrhagic fever (dhf) and dengue shock syndrome (dss). vascular leakage and hemorrhagic syndrome are the clinical features associated with dengue infection, yet the mechanisms remain unclear. in this study, the cross-reactivity of dengue patient sera with endothelial cells was demonstrated. there were higher percentages of endothelial cells reactive with dengue hemor ... | 2003 | 12436482 |
| [isolation, identification and sequence analyses of dengue virus type 2 strain gd19/2001]. | to identify the virus isolated from jiangmen, guangdong province and to discuss the possible origin. | 2003 | 12820947 |
| dengue virus type 2 ns3 protease and ns2b-ns3 protease precursor induce apoptosis. | apoptosis was detected in vero cell cultures expressing transfected dengue virus type 2 (denv-2) genes. approximately 17.5 and 51.5 % of cells expressing ns3 serine protease and ns2b-ns3(185) serine protease precursor protein [ns2b-ns3(185)(pro)] genes, respectively, were apoptotic. the percentage of apoptotic cells was significantly higher in cell cultures expressing ns2b-ns3(185)(pro). ns2b-ns3(185)(pro) was detected as ns2b-ns3(185)(pro)-egfp fusion protein in cytoplasmic vesicular structures ... | 2003 | 12867651 |
| vaccination of rhesus macaques against dengue-2 virus with a plasmid dna vaccine encoding the viral pre-membrane and envelope genes. | a nucleic acid vaccine for dengue-2 virus was developed, consisting of a plasmid dna vector with the pre-membrane (prm) and envelope (e) genes expressed from a cytomegalovirus promoter. the dna was adsorbed onto gold microspheres for administration by a gene gun. expression was demonstrated by transfection of mouse cells in culture where the prm and e antigens were detected intracellularly, and the e antigen was detected in the culture supernatant fluid, similar to a natural infection. the vacci ... | 2003 | 12875299 |
| comparative immunological recognition of proteins from new guinea "c" dengue virus type 2 prototype and from a dengue virus type 2 strain isolated in the state of rio de janeiro, brazil. | the protein profiles of the new guinea "c" dengue virus type 2 (denv-2)prototype and those of a brazilian denv-2 isolated in the state of rio de janeiro in 1995 were compared. sds-page analysis showed that the virus from rio de janeiro expresses ns5 (93.0 kda), ns3 (66.8 kda) e (62.4 kda) and ns1 (41.2 kda) proteins differently from the new guinea "c" virus. the immunoblot revealed specificity and antigenicity for the ns3 protein from denv-2 rio de janeiro mainly in primary infections, convalesc ... | 2003 | 12886411 |
| translation efficiency determines differences in cellular infection among dengue virus type 2 strains. | we have investigated the molecular basis for differences in the ability of natural variants of dengue virus type 2 (den2) to replicate in primary human cells. the rates of virus binding, virus entry, input strand translation, and rna stability of low-passage thai and nicaraguan and prototype den2 strains were compared. all strains exhibited equivalent binding, entry, and uncoating, and displayed comparable stability of positive strand viral rna over time in primary cells. however, the low-passag ... | 2003 | 14698666 |
| risk factors for infection during a severe dengue outbreak in el salvador in 2000. | in 2000, el salvador experienced a large dengue-2 virus epidemic with many severe cases. a seroepidemiologic survey was conducted in 106 randomly selected households (501 residents) in an affected community (las pampitas). the frequency of recent infection, documented by the presence of igm antibodies or high-titer igg antibodies to dengue virus, was estimated to be 9.8% (95% confidence interval [ci] = 5.8-13.7), of which at least 44% were secondary infections. the number of containers positive ... | 2003 | 14740880 |
| enhanced vector competence of aedes aegypti (diptera: culicidae) from the torres strait compared with mainland australia for dengue 2 and 4 viruses. | australian aedes aegypti (l.) mosquitoes colonized from the torres strait and three mainland localities (charters towers, townsville, and cairns) were fed on blood suspensions containing dengue virus type 2 (den-2) or dengue virus type 4 (den-4). variation was found in oral susceptibility to den-2 (59 -99% infection) and den-4 (28-79% infection) among ae. aegypti assayed for virus at 8, 12, 16, or 20 d after ingestion of infected blood. torres strait ae. aegypti were the most susceptible to den- ... | 2003 | 14765675 |
| enhanced esterase activity in salivary gland and midgut of aedes aegypti mosquito infected with dengue-2 virus. | mosquitoes were infected by intrathoracic inoculation. about 95% head squashes were positive for dengue virus antigen on the 15th post infection day (pid). esterase activity was determined in the homogenates prepared from the salivary glands and midguts on different pids of dengue virus inoculated and control mosquitoes showed that it was consistently higher in the virus-infected batches. | 2003 | 15267144 |
| anti-tnf antibody treatment reduces mortality in experimental dengue virus infection. | here we describe a lethal mouse model infected with dengue virus type 2 with several similarities to human den-2 infection. clinically animals demonstrated anemia, thrombocytopenia, pre-terminal paralysis and shock. the most impressive changes were seen with tumor necrosis factor (tnf)-alpha, which abruptly and steeply increased 24 h before the exitus (mean at day 6). serum levels of il-1beta, il-6, il-10, il-1 receptor antagonist and soluble tnf receptor i continuously increased during the time ... | 2003 | 12589955 |
| supernatants from dengue virus type-2 infected macrophages induce permeability changes in endothelial cell monolayers. | the ability of dengue virus-infected human monocyte-derived macrophages to induce permeability changes in primary human umbilical vein endothelial cells was investigated. supernatants from dengue virus type 2-infected monocyte-derived macrophages increased permeability in human umbilical vein endothelial cell monolayers without inducing endothelial cell infection. production of permeabilising activity from monocyte-derived macrophages occurred after the peak of progeny virus release. tnf-alpha, ... | 2003 | 12601760 |
| yellow fever virus/dengue-2 virus and yellow fever virus/dengue-4 virus chimeras: biological characterization, immunogenicity, and protection against dengue encephalitis in the mouse model. | two yellow fever virus (yfv)/dengue virus chimeras which encode the prm and e proteins of either dengue virus serotype 2 (dengue-2 virus) or dengue-4 virus within the genome of the yfv 17d strain (yf5.2iv infectious clone) were constructed and characterized for their properties in cell culture and as experimental vaccines in mice. the prm and e proteins appeared to be properly processed and glycosylated, and in plaque reduction neutralization tests and other assays of antigenic specificity, the ... | 2003 | 12610141 |
| enhancing biosynthesis and secretion of premembrane and envelope proteins by the chimeric plasmid of dengue virus type 2 and japanese encephalitis virus. | we have constructed a series of plasmids encoding premembrane (prm) and envelope (e) protein genes of dengue virus type 2 (den-2). these plasmids included an authentic den-2 prm-e construct (pcbd2-14-6), and two chimeric constructs, 90% den-2 e-10% japanese encephalitis (je) virus e (pcb9d2-1j-4-3) and 80% den-2 e-20% je e (pcb8d2-2j-2-9-1). monoclonal antibody (mab) reactivity indicated that all three plasmids expressed authentic den-2 virus e protein epitopes representative of flavivirus domai ... | 2003 | 12620809 |
| steady-state cleavage kinetics for dengue virus type 2 ns2b-ns3(pro) serine protease with synthetic peptides. | the n-terminal part of the ns3 protein from dengue virus contains a trypsin-like serine protease responsible for processing the nonstructural region of the viral polyprotein. enzymatic activity of the ns2b-ns3(pro) precursor incorporating a full-length ns2b cofactor of dengue virus type 2 was examined by using synthetic dodecamer peptide substrates encompassing native cleavage sequences of the ns2a/ns2b, ns2b/ns3, ns3/ns4a and ns4b/ns5 polyprotein junctions. cleavage of the dansylated substrates ... | 2003 | 12625822 |
| american genotype structures decrease dengue virus output from human monocytes and dendritic cells. | the dengue virus type 2 structures probably involved in human virulence were previously defined by sequencing the complete genome of both american and southeast (se) asian genotype templates in patient serum (k. c. leitmeyer et al., j. virol. 73:4738-4747, 1999). we have now evaluated the effects of introducing a mutation in the envelope glycoprotein (e) gene and/or replacement of 5'- and 3'-nontranslated regions on dengue virus replication in human primary cell cultures. a series of chimeric in ... | 2003 | 12634353 |
| diverse dengue type 2 virus populations contain recombinant and both parental viruses in a single mosquito host. | envelope (e) protein genes sampled from populations of dengue 2 (den-2) virus in individual aedes aegypti mosquitoes and in serum from dengue patients were copied to cdna, cloned, and sequenced. the nucleotide sequences of the e genes in more than 70% of the clones differed from the consensus sequence for the corresponding virus population at up to 11 sites, and 24 of the 94 clones contained at least one stop codon. virus populations recovered up to 2 years apart yielded clones with similar poly ... | 2003 | 12634407 |
| amplification of the sylvatic cycle of dengue virus type 2, senegal, 1999-2000: entomologic findings and epidemiologic considerations. | after 8 years of silence, dengue virus serotype 2 (denv-2) reemerged in southeastern senegal in 1999. sixty-four denv-2 strains were isolated in 1999 and 9 strains in 2000 from mosquitoes captured in the forest gallery and surrounding villages. isolates were obtained from previously described vectors, aedes furcifer, ae. taylori, ae. luteocephalus, and--for the first time in senegal--from ae. aegypti and ae. vittatus. a retrospective analysis of sylvatic denv-2 outbreaks in senegal during the la ... | 2003 | 12643833 |
| secreted expression of dengue virus type 2 full-length envelope glycoprotein in pichia pastoris. | the full-length envelope glycoprotein gene of dengue virus type 2 was cloned using an rt-pcr method from the infected c6/36 cells and inserted into ppiczab vector. the recombinant plasmid was integrated into pichia pastoris by electroporation and the expressed product was identified by sds-page and western blotting. high-level secreted expression was performed by determining the mut(+) phenotype and screening multi-copy integrants in the recombinant yeast cells. a recombinant protein with a mole ... | 2003 | 12668263 |
| production of anti-dengue ns1 monoclonal antibodies by dna immunization. | monoclonal antibodies against dengue ns1 protein were generated following immunization of mice with plasmid dna encoding the transmembrane form of ns1 from dengue serotype 2 virus. a mammalian expression vector, pdisplay, was engineered to direct cell surface expression of dengue ns1 and tested for transient expression in cos cells. two mice were immunized intramuscularly with six doses of 100 microg of plasmid at 2-week intervals; one mouse received a booster of live virus prior to the last pla ... | 2003 | 12668268 |
| molecular typing of dengue virus type 2 in brazil. | strain typing is a critical tool for molecular epidemiological analysis and can provide important information about the spread of dengue viruses. here, we performed a molecular characterization of den-2 viruses isolated in brazil during 1990-2000 from geographically and temporally distinct areas in order to investigate the genetic distribution of this serotype circulating in the country. restriction site-specific polymerase chain reaction (rss)-pcr presented the same pattern for all 52 brazilian ... | 2003 | 12751317 |
| a ligand-binding pocket in the dengue virus envelope glycoprotein. | dengue virus is an emerging global health threat. its major envelope glycoprotein, e, mediates viral attachment and entry by membrane fusion. a crystal structure of the soluble ectodomain of e from dengue virus type 2 reveals a hydrophobic pocket lined by residues that influence the ph threshold for fusion. the pocket, which accepts a hydrophobic ligand, opens and closes through a conformational shift in a beta-hairpin at the interface between two domains. these features point to a structural pa ... | 2003 | 12759475 |
| tick-borne encephalitis with hemorrhagic syndrome, novosibirsk region, russia, 1999. | eight fatal cases of tick-borne encephalitis with an unusual hemorrhagic syndrome were identified in 1999 in the novosibirsk region, russia. to study these strains, we sequenced cdna fragments of protein e gene from six archival formalin-fixed brain samples. phylogenetic analysis showed tick-borne encephalitis variants clustered with a far eastern subtype (homology 94.7%) but not with the siberian subtype (82%). | 2003 | 12781020 |
| dengue virus envelope glycoprotein structure: new insight into its interactions during viral entry. | 2003 | 12782795 | |
| evaluation of protective efficacy and immune mechanisms of using a non-structural protein ns1 in dna vaccine against dengue 2 virus in mice. | to evaluate the potential of dna vaccine against dengue (den) infection, we characterize the protective efficacy and immune responses of mice intramuscularly injected with plasmid encoding den-2 non-structural protein 1 (ns1). intravenously challenged by lethal den-2, mice vaccinated with ns1-dna exhibited a delay onset of paralysis, a marked decrease of morbidity, and a significant enhancement of survival. in addition to a moderate increase of ns1-specific antibody titer from immunized mice mea ... | 2003 | 12922127 |
| blocking the dengue virus 2 infections on bhk-21 cells with purified recombinant dengue virus 2 e protein expressed in escherichia coli. | dengue viruses (dvs) are mosquito-borne infectious pathogens. they have become an expanding public health problem in the tropics and subtropics. the dengue envelope (e) protein is one of the viral structure proteins responsible mainly for the virus attachment and entry onto host cells. it is also the major immunogen for virus neutralization. in this study, we have constructed a recombinant plasmid expressing a truncated e protein of dv-2 virus pl046 strain. the c-terminal hydrophobic domain of t ... | 2003 | 12963043 |
| aedes aegypti in south vietnam: ecology, genetic structure, vectorial competence and resistance to insecticides. | in vietnam, dengue hemorrhagic fever has been detected since the 1950s. in southeast asia, urban centers expanded rapidly in an uncontrolled and unplanned way. the aedes aegypti populations and dengue viruses thrived in these new ecological and demographic settings. the result of these changes was a greatly extended geographic distribution, increased densities of ae. aegypti and the maintenance of the four dengue serotypes leading to a dramatic increase in dengue transmission. to assess the role ... | 2003 | 12971518 |
| identification of a dengue virus type 2 (den-2) serotype-specific b-cell epitope and detection of den-2-immunized animal serum samples using an epitope-based peptide antigen. | in this study, a serotype-specific monoclonal antibody (mab), d(2) 16-1 (ab4), against dengue virus type 2 (den-2) was generated. the specificity of ab4, which recognized den-2 non-structural protein 1, was determined by elisa, immunofluorescence and immunoblotting analyses. the serotype-specific b-cell epitope of ab4 was identified further from a random phage-displayed peptide library; selected phage clones reacted specifically with ab4 and did not react with other mabs. immunopositive phage cl ... | 2003 | 13679612 |
| substitution of the structural genes of dengue virus type 4 with those of type 2 results in chimeric vaccine candidates which are attenuated for mosquitoes, mice, and rhesus monkeys. | antigenic chimeric viruses in which the structural genes of dengue virus type 4 (den4) have been replaced with those derived from dengue virus type 2 (den2) have been created and evaluated as a first step in generating a live attenuated tetravalent dengue virus vaccine. specifically, the capsid, membrane precursor, and envelope (cme) or the membrane precursor and envelope (me) gene regions of den2 were substituted for the corresponding genes of wild-type rden4 or vaccine candidate rden4delta30 w ... | 2003 | 14505913 |
| mutations which enhance the replication of dengue virus type 4 and an antigenic chimeric dengue virus type 2/4 vaccine candidate in vero cells. | mutations which increase the replication of dengue viruses in cell culture would greatly facilitate the manufacture of both a live attenuated or inactivated dengue virus vaccine. we have identified eight missense mutations in dengue virus type 4 (den4) that increase the plaque size and kinetics of replication of recombinant den4 virus in vero cells. den4 viruses bearing these vero cell adaptation mutations were also evaluated for the level of replication in the brains of mice. two of these eight ... | 2003 | 14505914 |
| e/ns1 modifications of dengue 2 virus after serial passages in mammalian and/or mosquito cells. | dengue viruses are routinely maintained in nature by transmission cycles involving the passage of virus between humans and aedes mosquitoes. the number of dengue virus lineages has been increasing over time. the aim of this study was to identify the genetic diversity of dengue 2 virus serially transferred in mammalian and/or mosquito cells. | 2003 | 14555849 |
| dengue virus type 2 infects human endothelial cells through binding of the viral envelope glycoprotein to cell surface polypeptides. | the endothelial cell line ecv304, derived from human umbilical cord and identified to be susceptible to dengue virus type 2 (den-2) infection, was used to study the molecular mechanism of den-2 binding to endothelial cells. den-2 was found by virus overlay protein-binding assays (vopbas) to bind to three ecv304 cell membrane proteins with molecular masses of 29, 34 and 43 kda. only a single protein of 29 kda was observed when vopbas were carried out using preparations of trypsin-treated ecv304 c ... | 2003 | 14573814 |
| virucidal activity of essential oils from aromatic plants of san luis, argentina. | essential oils obtained from eight aromatic plants of san luis province, argentina, were screened for virucidal activity against herpes simplex virus type 1 (hsv-1), junin virus (junv) and dengue virus type 2 (den-2). the most potent inhibition was observed with the essential oil of lippia junelliana and lippia turbinata against junv with virucidal concentration 50% (vc(50)) values in the range 14-20 ppm, whereas aloysia gratissima, heterotheca latifolia and tessaria absinthioides inhibited junv ... | 2003 | 14595590 |
| replication-defective adenoviral vaccine vector for the induction of immune responses to dengue virus type 2. | a recombinant replication-defective adenovirus vector that can overexpress the ectodomain of the envelope protein of dengue virus type 2 (ngc strain) has been constructed. this virus was immunogenic in mice and elicited dengue virus type 2 specific b- and t-cell responses. sera from immunized mice contained neutralizing antibodies that could specifically recognize dengue virus type 2 and neutralize its infectivity in vitro, indicating that this approach has the potential to confer protective imm ... | 2003 | 14610213 |
| potential development of temephos resistance in aedes aegypti related to its mechanism and susceptibility to dengue virus. | the addition of temephos to water containers as a larvicide against aedes aegypti was commonly used as a part of dhf control programs. the widespread, or long-term, application of insecticides can lead to the development of mosquito resistance to the insecticides through selection pressure. this presents a problem for disease control. therefore, this study was conducted in the laboratory to observe the potential development of resistance to temephos and the mechanism involved in ae. aegypti, and ... | 2003 | 19230585 |
| study on the determinants of suckling mice neurovirulence of dengue 2 virus. | pdvws501 was a genomic-length cdna clone of dengue 2 virus, through which infectious virus (mon501) could be rescued. mon501 was neurovirulent in mice, whose e residues 62 and 203 were lys and asn, respectively. two genomic-length cdna clones (tb62 and tb203) were constructed by pointed mutation of pdvws501 with ol-pcr, e62 of tb62 and e203 of tb203 were converted to glu and asp, respectively. rna transcripts of pdvws501, tb62 and tb203 were produced in vitro and electroporated into bhk-21 cells ... | 2003 | 20213366 |
| a dengue-2 envelope fragment inserted within the structure of the p64k meningococcal protein carrier enables a functional immune response against the virus in mice. | a gene fragment encoding for the amino acids (aa) 286-426 from the dengue envelope (e) protein was expressed in escherichia coli as two forms of fusion proteins. in one case, the e fragment was fused to the first 45 aa of the p64k protein from neisseria meningitidis (pd2) while, in the other, it was inserted within the lipoil-binding domain of the aforementioned bacterial protein (pd3). pd2 was obtained as insoluble form within the cytoplasm of the bacteria while pd3 was distributed equally as s ... | 2004 | 14656459 |
| an external loop region of domain iii of dengue virus type 2 envelope protein is involved in serotype-specific binding to mosquito but not mammalian cells. | dengue virus (dv) is a flavivirus and infects mammalian cells through mosquito vectors. this study investigates the roles of domain iii of dv type 2 envelope protein (eiii) in dv binding to the host cell. recombinant eiii interferes with dv infection to bhk21 and c6/36 cells by blocking dengue virion adsorption to these cells. inhibition of eiii on bhk21 cells was broad with no serotype specificity; however, inhibition of eiii on c6/36 cells was relatively serotype specific. soluble heparin comp ... | 2004 | 14671119 |
| tetracycline-inducible packaging cell line for production of flavivirus replicon particles. | we have previously developed replicon vectors derived from the australian flavivirus kunjin that have a unique noncytopathic nature and have been shown to direct prolonged high-level expression of encoded heterologous genes in vitro and in vivo and to induce strong and long-lasting immune responses to encoded immunogens in mice. to facilitate further applications of these vectors in the form of virus-like particles (vlps), we have now generated a stable bhk packaging cell line, tetkuncprme, carr ... | 2004 | 14671135 |
| high-level expression and one-step purification of recombinant dengue virus type 2 envelope domain iii protein in escherichia coli. | dengue virus infection poses a serious global public health threat for which there is currently no therapy or a licensed vaccine. the domain iii of the dengue virus encoded envelope protein, which carries multiple conformation-dependent neutralizing epitopes, is critical for virus infectivity. we have expressed and purified recombinant domain iii of dengue virus type-2 envelope, without the aid of a carrier protein in escherichia coli. a 6x his tag was inserted at the n terminus to facilitate it ... | 2004 | 14680965 |
| identification of the homotypic interaction domain of the core protein of dengue virus type 2. | dengue virus causes dengue haemorrhagic fever or dengue shock syndrome with a high mortality rate. the genome of dengue virus is a positive-sense, single-stranded rna encoding three structural and seven non-structural proteins. the core protein is one of the three structural proteins and is the building block of the nucleocapsid of dengue virus. the core protein of dengue virus type 2 (den2) is composed of 100 aa with four alpha-helix domains. an internal hydrophobic domain located at aa 44-60 w ... | 2004 | 15269372 |
| development of cell lines stably expressing staphylococcal nuclease fused to dengue 2 virus capsid protein for ctvi. | to explore the potential application of capsid-targeted viral inactivation (ctvi) strategy in prophylactic model against dengue virus (dv) infection, here we fused a ca(2+)-dependent nuclease, staphylococcal nuclease (sn), to the capsid protein of dengue 2 virus (d2c) at the carboxyl terminal, and constructed the desired expression plasmid pc/d2c-sn and control plasmids pc/d2c-sn* and pc/d2c. a mammalian cell line bhk-21 was transfected by electroporation with those plasmids and thereafter selec ... | 2004 | 15295652 |
| fusion pcr generated japanese encephalitis virus/dengue 4 virus chimera exhibits lack of neuroinvasiveness, attenuated neurovirulence, and a dual-flavi immune response in mice. | the first flavivirus chimera encoding dengue 4 virus (d4) prm and e structural proteins in a japanese encephalitis virus (jev) backbone was successfully generated using the long-pcr based cdna-fragment stitching (lpcrcfs) technique, demonstrating the technique's applicability for rapid preparation of flavivirus chimeras. the jev/d4 chimera multiplied at levels equal to jev and d4 in the mosquito cell line c6/36, while in a mouse neuronal cell line (n2a) jev replicated efficiently, but jev/d4 and ... | 2004 | 15302944 |
| analysis of recombinant dengue virus polypeptides for dengue diagnosis and evaluation of the humoral immune response. | dengue is a serious cause of morbidity and mortality in tropical areas worldwide. we cloned and expressed recombinant polypeptides spanning the entire genome of a brazilian dengue virus type 2 (denv-2) strain in contiguous segments to generate antigens for dengue diagnosis and evaluation of the human humoral immune response. when analyzed by western blot and an enzyme-linked immunosorbent assay (elisa) using human sera, the most reactive polypeptide (pd2-3(e)) was located in the n-terminal porti ... | 2004 | 15306702 |
| conformational changes of the flavivirus e glycoprotein. | dengue virus, a member of the flaviviridae family, has a surface composed of 180 copies each of the envelope (e) glycoprotein and the membrane (m) protein. the crystal structure of an n-terminal fragment of e has been determined and compared with a previously described structure. the primary difference between these structures is a 10 degrees rotation about a hinge relating the fusion domain dii to domains di and diii. these two rigid body components were used for independent fitting of e into t ... | 2004 | 15341726 |
| a 7-deaza-adenosine analog is a potent and selective inhibitor of hepatitis c virus replication with excellent pharmacokinetic properties. | improved treatments for chronic hepatitis c virus (hcv) infection are needed due to the suboptimal response rates and deleterious side effects associated with current treatment options. the triphosphates of 2'-c-methyl-adenosine and 2'-c-methyl-guanosine were previously shown to be potent inhibitors of the hcv rna-dependent rna polymerase (rdrp) that is responsible for the replication of viral rna in cells. here we demonstrate that the inclusion of a 7-deaza modification in a series of purine nu ... | 2004 | 15388457 |
| vaccine candidates derived from a novel infectious cdna clone of an american genotype dengue virus type 2. | a dengue virus type 2 (den-2 tonga/74) isolated from a 1974 epidemic was characterized by mild illness and belongs to the american genotype of den-2 viruses. to prepare a vaccine candidate, a previously described 30 nucleotide deletion (delta30) in the 3' untranslated region of den-4 has been engineered into the den-2 isolate. | 2004 | 15461822 |
| the role of hemagglutinins in the midgut extracts of two lines of aedes aegypti in their susceptibility to dengue-2 virus. | hemagglutinin activity (ha) was studied in the midgut extracts from highly (h) and lowly susceptible strains of aedes aegypti mosquitoes to dengue-2 virus (den-2). ha in the midgut extracts from these two isofemale strains of mosquitoes was high in as compared to (h) mosquitoes. ha was found to be higher with chicken red blood cells (rbcs) than with rabbit and human rbcs of o group. larval midgut extracts showed higher activity than those from adult female mosquitoes. exposure of midgut extracts ... | 2004 | 15462286 |
| introduction of the american/asian genotype of dengue 2 virus into the yucatan state of mexico. | a dengue (den) outbreak occurred in the yucatan state of mexico in 2002. three isolates were obtained from patients presenting with den-like symptoms, and examined by partial nucleotide sequencing and phylogenetic analysis. the isolates were identified as den-2 viruses of the american-asian genotype; this is the first report of this genotype in the yucatan state. the den-2 viruses of the american-asian genotype have been associated with more severe disease outcomes. thus, its introduction into t ... | 2004 | 15516647 |
| epitope determinants of a chimpanzee fab antibody that efficiently cross-neutralizes dengue type 1 and type 2 viruses map to inside and in close proximity to fusion loop of the dengue type 2 virus envelope glycoprotein. | the epitope determinants of chimpanzee fab antibody 1a5, which have been shown to be broadly reactive to flaviviruses and efficient for cross-neutralization of dengue virus type 1 and type 2 (denv-1 and denv-2), were studied by analysis of denv-2 antigenic variants. sequence analysis showed that one antigenic variant contained a gly-to-val substitution at position 106 within the flavivirus-conserved fusion peptide loop of the envelope protein (e), and another variant contained a his-to-gln subst ... | 2004 | 15542644 |
| histopathological aspects of dengue-2 virus infected mice tissues and complementary virus isolation. | the difficulty in studying dengue virus (denv) infection in humans and in developing a virus vaccine is the absence of a suitable animal model which develops the full spectra of the dengue haemorrhagic fever (dhf) and dengue shock syndrome (dss). despite the fact that viruses have been found in various animal tissues, we isolated denv from tissues of adult balb/c mice, inoculated with denv serotype 2 (denv-2) obtained from human serum. viruses were ultrastructurally identified and immunolocalize ... | 2004 | 15554498 |
| histidine 39 in the dengue virus type 2 m protein has an important role in virus assembly. | the mature flavivirus particle comprises a nucleocapsid core surrounded by a lipid bilayer containing the membrane (m) (derived from the precursor prm) and envelope (e) proteins. the formation of intracellular prm/e heterodimers occurs rapidly after translation and is believed to be important for the assembly and secretion of immature virus particles. in this study, the role of the his residue at position 39 in the m protein (m39) of dengue virus type 2 (denv-2) in the virus life cycle was inves ... | 2004 | 15557235 |
| identification of residues in the dengue virus type 2 ns2b cofactor that are critical for ns3 protease activation. | proteolytic processing of the dengue virus polyprotein is mediated by host cell proteases and the virus-encoded ns2b-ns3 two-component protease. the ns3 protease represents an attractive target for the development of antiviral inhibitors. the three-dimensional structure of the ns3 protease domain has been determined, but the structural determinants necessary for activation of the enzyme by the ns2b cofactor have been characterized only to a limited extent. to test a possible functional role of t ... | 2004 | 15564480 |
| dengue virus type 2 in cuba, 1997: conservation of e gene sequence in isolates obtained at different times during the epidemic. | it was recently reported that disease severity increased during the 1997 cuban dengue 2 virus epidemic and it was suggested that this might be explained by the appearance of neutralization resistant escape mutants. we investigated these observations and ideas by sequencing 20 dengue 2 virus isolates obtained during the early (low case fatality rate) and the late (high case fatality rate) phases of the outbreak. our results showed total conservation of the e gene sequence for these isolates sugge ... | 2004 | 15578237 |