| comparison of two rapid diagnostic assays for detection of immunoglobulin m antibodies to dengue virus. | two easy-to-use commercial diagnostic assays, a dipstick enzyme-linked immunosorbent assay (elisa) (integrated diagnostics, baltimore, md.) and an immunochromatographic card assay (panbio, brisbane, australia) were evaluated for detection of immunoglobulin m (igm) antibody to dengue virus with an in-house igm antibody capture microplate elisa as a reference assay. the dipstick elisa was based on the indirect-elisa format using dengue 2 virus as the only antigen and enzyme-labeled goat anti-human ... | 2000 | 10618287 |
| [the specific epidemiological surveillance of dengue: the method and its importance since the dengue-2 epidemic in french polynesia in 1996]. | dengue fever is present in tropical and subtropical regions and its geographical extension and the simultaneous increase of its mortality are worrisome. in endemic or epidemic countries, the aim of dengue-specific epidemiological surveillance is to confirm as soon as possible the circulation of a new viral dengue serotype, i.e. the beginning of an epidemic. the efficiency of the control strategy is improved by an earlier epidemic alert. in french polynesia, dengue-3 virus circulated since 1989 a ... | 1998 | 9705191 |
| the 1993 dengue 2 epidemic in charters towers, north queensland: clinical features and public health impact. | in 1993 an epidemic caused by dengue virus type 2 occurred in several north queensland population centres. charters towers, estimated population 10,000, had 155 officially notified cases. an analysis of symptoms was undertaken using a random sample of 1000 residents to determine specificity of symptoms, the subclinical infection rate, and to establish the true extent of the epidemic. retrospective diagnoses of dengue fever were based on the presence of both serum dengue 2 neutralizing antibody a ... | 1998 | 9747766 |
| detection and genetic relationship of dengue virus sequences in seventeen-year-old paraffin-embedded samples from cuba. | this study describes the use of the reverse transcriptase-polymerase chain reaction (rt-pcr) to generate dengue 2 amplicons from paraffin-embedded autopsy tissues collected in cuba 17 years ago. the presumptive diagnoses had been made only by clinical evolution without serologic confirmation. this study confirms once again that dengue 2 virus was directly associated with the fatal cases in children and illustrates the potential of the rt-pcr for retrospective diagnosis of dengue cases 17 years a ... | 1999 | 10674684 |
| the 1993 dengue 2 epidemic in north queensland: a serosurvey and comparison of hemagglutination inhibition with an elisa. | an epidemic of dengue type 2 infection occurred in north queensland during 1992 and 1993. a random serosurvey of 1,000 residents of a population that experienced this epidemic only during 1993 was conducted to determine the proportion of the population at risk for secondary infection in the event of another epidemic with a different serotype. the ability of an elisa to detect prior exposure to the dengue virus was compared with the hemagglutination inhibition assay. dengue 2 virus plaque-reducti ... | 1998 | 9749644 |
| dengue encephalitis in french guiana. | thousands of cases of dengue fever (df) and several cases of dengue haemorrhagic fever were recorded in french guiana during the recent outbreak of dengue-2 virus (1991-1992) and in subsequent years. one case with clinical signs typical of classical df with neurological complications is reported in this study. the neurological features (encephalitis) appeared during the acute phase, 2 days after the onset of fever. dengue-2 virus was detected in both the cerebrospinal fluid and blood sample. thi ... | 1998 | 9783339 |
| 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 ... | 1998 | 9820138 |
| analysis of antibody-independent binding of dengue viruses and dengue virus envelope protein to human myelomonocytic cells and b lymphocytes. | the identification of cell surface receptor molecules for the dengue viruses, one of the leading causes of morbidity and mortality in tropical and subtropical parts of the world, remains controversial. both glycoproteins and glycosaminoglycans have been identified as likely candidates on various cell types. however, most of these studies have used cell types other than those thought to be the main target cells in humans: monocyte-macrophages, b lymphocytes and bone marrow cells. in this report c ... | 1998 | 9833887 |
| aedes aegypti in ho chi minh city (viet nam): susceptibility to dengue 2 virus and genetic differentiation. | aedes aegypti is the principal vector of dengue viruses, responsible for a viral infection that has become a major public health concern in asia. in viet nam, dengue haemorrhagic fever was first detected in the 1960s and is now a leading cause of death in childhood. we studied the variability in competence of ae. aegypti as a vector for dengue 2 virus and genetic differentiation in this mosquito species. twenty mosquito samples collected in 1998 in ho chi minh city were subjected to oral infecti ... | 1999 | 10717737 |
| antibody responses to an immunodominant nonstructural 1 synthetic peptide in patients with dengue fever and dengue hemorrhagic fever. | two flaviviruses, dengue (den) virus and japanese encephalitis (je) virus, are important because of their global distribution and the frequency of epidemics in tropical and subtropical areas. to study the b-cell epitopes of nonstructural 1 (ns1) glycoprotein and anti-ns1 antibody response in den infection, a series of 15-mer synthetic peptides from the predicted b-cell linear epitopes of den-2 ns1 protein were prepared. enzyme-linked immunosorbent assay (elisa) was performed to analyze antibody ... | 1999 | 9890415 |
| the use of direct sequencing of dengue virus cdna from individual field-collected aedes aegypti for surveillance and epidemiological studies. | the relative efficiencies of four methods to extract viral rna from individual dengue-2 virus (d-2v)-infected mosquitoes, aedes aegypti (l.) (diptera: culicidae), were compared. the most efficient of these methods was then used to extract viral rna for the preparation of cdna from the abdomens of six engorged d-2v-infected mosquitoes and sera from three dengue fever (df) patients collected in an isolated rural town in colombia. comparisons of viral envelope (e) gene sequences from each of these ... | 2000 | 10759317 |
| [epidemic outbreak of dengue virus 2/jamaica genotype in bolivia]. | to confirm an epidemic outbreak of dengue virus in the city of santa cruz, bolivia, and to determine the serotype of the virus, to estimate the rate of attack and the proportion of symptomatic infections. | 1998 | 9927881 |
| [dengue epidemic in fortaleza, ceará: randomized seroepidemiologic survey]. | a seroepidemiological random survey was carried out in fortaleza city, state of ceará, brazil, following an epidemic of dengue virus type 2 (den 2), with the purpose of evaluating the frequency of clinical manifestations (signs and symptoms) and the prevalence of dengue infection. | 1998 | 10030061 |
| aedes aegypti in tahiti and moorea (french polynesia): isoenzyme differentiation in the mosquito population according to human population density. | genetic differences at five polymorphic isoenzyme loci were analyzed by starch gel electrophoresis for 28 aedes aegypti samples. considerable (i.e., high fst values) and significant (i.e., p values >10(-4)) geographic differences were found. differences in ae. aegypti genetic structure were related to human population densities and to particularities in mosquito ecotopes in both tahiti and moorea islands. in highly urbanized areas (i.e., the papeete agglomeration), mosquitoes were highly structu ... | 2000 | 10813476 |
| maturation site of dengue type 2 virus in cultured mosquito c6/36 cells and vero cells. | the maturation of dengue virus (type 2, new guinea b strain; abbreviated den-2) in cultured mosquito c3/36 cells and vero cells was studied by immunoelectron microscopy for the first 7 days after cells were infected, assays of the virus were done by the peroxidase-antiperoxidase method. virus titers in both kinds of cells were highest on day 6. these cells were then observed with an electron microscope. den-2 was round and measured about 50 nm in diameter. the virus matured mainly at the membran ... | 1998 | 10036861 |
| recombinant chimeric yellow fever-dengue type 2 virus is immunogenic and protective in nonhuman primates. | a chimeric yellow fever (yf)-dengue type 2 (dengue-2) virus (chimerivax-d2) was constructed using a recombinant cdna infectious clone of a yf vaccine strain (yf 17d) as a backbone into which we inserted the premembrane (prm) and envelope (e) genes of dengue-2 virus (strain puo-218 from a case of dengue fever in bangkok, thailand). the chimeric virus was recovered from the supernatant of vero cells transfected with rna transcripts and amplified once in these cells to yield a titer of 6.3 log(10) ... | 2000 | 10823852 |
| 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 ... | 1999 | 10074162 |
| analysis of the steps involved in dengue virus entry into host cells. | the initial steps of dengue viral entry have been divided into adsorption and penetration using acid glycine treatment to inactivate extracellular virus after attachment to baby hamster kidney (bhk) cells but prior to penetration. first, we showed that virus infection was accomplished within 2 h after adsorption. second, the assay was used to examine the properties of dengue envelope e protein-specific monoclonal antibodies (mabs), lectins, and heparin. we found that three mabs, 17-2, 46-9, and ... | 1999 | 10208929 |
| plasma levels of tumour necrosis factor alpha and transforming growth factor beta-1 in children with dengue 2 virus infection in french polynesia. | the pathogenesis of dengue haemorrhagic fever (dhf) is not well understood. in the absence of predictive clinical or biological criteria, the management of dhf patients remains difficult. the role played by cytokines in the occurrence of dhf has been suggested by several authors. in this study, we determined the plasma levels of tumour necrosis factor alpha (tnf alpha) and transforming growth factor beta-1 (tgf beta-1) in 52 children with laboratory-confirmed dengue virus infection admitted to h ... | 1998 | 10326113 |
| [assessment of the cellular immune response induced in balb/c mice with dengue virus 2 envelope protein]. | the cellular immune response to dengue type 2 virus envelope protein was studied. to this end, the lympho-proliferative capacity of t-lymphocytes obtained from splenocytes of animals immunized with the protein when they were stimulated by such protein and dengue 2 virus. it was realized that splenocytes proliferated significantly in response to both types of viral antigens and that the values of stimulation indexes were higher in response to the whole virus than to the protein alone. based on th ... | 1999 | 10887567 |
| failure of dengue-2 virus antibody to interfere with the isolation of dengue-2 virus from aedes aegypti (diptera: culicidae). | when isolating dengue virus (den) from mosquitoes collected in endemic areas, pools may contain both anti-dengue antibodies from freshly engorged females and virus from den infected females. to determine if these antibodies may interfere with virus isolation, we simulated the isolation procedure using aedes aegypti (l.) that we infected with the 16,681 strain of dengue type 2 virus by intrathoracic inoculation. at 7 d postinfection, we allowed females to engorge on immunized or normal mouse bloo ... | 2000 | 10916310 |
| imported dengue virus type 2 infection acquired during an outbreak in india. | | 1999 | 10385025 |
| evaluation of four methods for detection of immunoglobulin m antibodies to dengue virus. | dengue has become hyperendemic in many islands of the caribbean region. the performance in a diagnostic laboratory of four commercial assays for detection of immunoglobulin m (igm) antibodies was evaluated. sera from 62 patients with dengue virus infection were studied. these included 18 patients from whom dengue virus type 2 was isolated in a 1997 outbreak (specimens collected a mean of 14 days after onset of symptoms), 8 patients with dengue hemorrhagic fever (mean time after onset, 11 days), ... | 1999 | 10391862 |
| identification of an epitope on the dengue virus membrane (m) protein defined by cross-protective monoclonal antibodies: design of an improved epitope sequence based on common determinants present in both envelope (e and m) proteins. | the protective capacity of monoclonal antibodies (mabs) generated to the dengue-2 virus envelope (e) and premembrane (prm) proteins was tested in vivo. two anti-e mabs, 2c5.1 and 4g2 and two anti-prm mabs, 2a4.1 and 2h2 provided cross-protection against all four dengue virus serotypes. overlapping sets of synthetic peptides spanning amino-acid sequence 301-401 (domain iii) of the e protein and the entire prm protein were then used to locate their epitopes. the anti-e mabs strongly reacted with t ... | 1999 | 10664386 |
| application of molecular typing techniques in the 1998 dengue epidemic in nicaragua. | this report presents the results of applying the reverse transcriptase-polymerase chain reaction (rt-pcr) to the analysis of clinical specimens during the 1998 dengue epidemic in nicaragua. the rt-pcr was validated through comparison with viral isolation, resulting in a sensitivity of 100% and a specificity of 90%. in-country application of the rt-pcr permitted the rapid identification of dengue-3 virus as the cause of the epidemic at the beginning of 1998 and the detection of the reintroduction ... | 1999 | 10674666 |
| light-independent inactivation of dengue-2 virus by carboxyfullerene c3 isomer. | carboxyfullerene (c60) is known as a photosensitizer for virus inactivation. its regioisomer with c3 symmetry, named the c3 isomer, could also inactivate the dengue-2 virus without light when the dose of c3 isomer was increased to 40 microm, indicating the possible involvement of a light-independent mechanism. further analysis showed that the c3 isomer blocked viral replication at the attachment and penetration stages, suggesting that a direct interaction between the c3 isomer and the virion is ... | 2000 | 10998325 |
| quantitative trait loci that control vector competence for dengue-2 virus in the mosquito aedes aegypti. | quantitative trait loci (qtl) affecting the ability of the mosquito aedes aegypti to become infected with dengue-2 virus were mapped in an f(1) intercross. dengue-susceptible a. aegypti aegypti were crossed with dengue refractory a. aegypti formosus. f(2) offspring were analyzed for midgut infection and escape barriers. in p(1) and f(1) parents and in 207 f(2) individuals, regions of 14 cdna loci were analyzed with single-strand conformation polymorphism analysis to identify and orient linkage g ... | 2000 | 11014816 |
| an antigen capture enzyme-linked immunosorbent assay reveals high levels of the dengue virus protein ns1 in the sera of infected patients. | we describe the development of a capture enzyme-linked immunosorbent assay for the detection of the dengue virus nonstructural protein ns1. the assay employs rabbit polyclonal and monoclonal antibodies as the capture and detection antibodies, respectively. immunoaffinity-purified ns1 derived from dengue 2 virus-infected cells was used as a standard to establish a detection sensitivity of approximately 4 ng/ml for an assay employing monoclonal antibodies recognizing a dengue 2 serotype-specific e ... | 2000 | 10698995 |
| 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 ... | 1999 | 10355763 |
| rapid detection of west nile virus from human clinical specimens, field-collected mosquitoes, and avian samples by a taqman reverse transcriptase-pcr assay. | the authors report on the development and application of a rapid taqman assay for the detection of west nile (wn) virus in a variety of human clinical specimens and field-collected specimens. oligonucleotide primers and fam- and tamra-labeled wn virus-specific probes were designed by using the nucleotide sequence of the new york 1999 wn virus isolate. the taqman assay was compared to a traditional reverse transcriptase (rt)-pcr assay and to virus isolation in vero cells with a large number ( app ... | 2000 | 11060069 |
| evaluation of six immunoassays for detection of dengue virus-specific immunoglobulin m and g antibodies. | the performance of six commercially available immunoassay systems for the detection of dengue virus-specific immunoglobulin m (igm) and igg antibodies in serum was evaluated. these included two igm and igg enzyme immunoassays (eia) from mrl laboratories and panbio, a rapid immunochromatographic test (rit) from panbio, immunofluorescence assays (ifa) from progen, a dot blot assay from genelabs, and a dipstick eia from integrated diagnostics (indx). for this study a panel of 132 serum samples, inc ... | 2000 | 11063489 |
| strain analysis and epitope mapping of west nile virus using monoclonal antibodies. | monoclonal antibodies (mabs) against an indian strain (804994) and an egyptian strain (e 101) of west nile virus (wnv) were prepared in mice. nine mabs against the 804994 strain and 5 mabs against e 101 strain were obtained. all 14 mabs reacted with the envelope (e) protein of wnv in an immunoblot assay. they were tested by an enzyme-linked immunosorbent assay (elisa) for their cross-reactivity with wnv, japanese encephalitis virus (jev) and dengue-2 virus (den-2), and for their reactivity in ha ... | 1998 | 10358745 |
| influence of the human high-affinity igg receptor fcgammari (cd64) on residual infectivity of neutralized dengue virus. | we examined dengue virus immune complex-phagocyte interaction with respect to a single fc receptor class using a transient expression system involving the high-affinity human macrophage receptor, fcgammari. we found that new guinea c strain dengue 2 virus formed well-defined plaques in normal and transfected cos cells and we analyzed the structural determinants of fcgammari-mediated binding and internalization of dengue 2 virus immune complexes by expressing native or truncated forms of the rece ... | 1999 | 10405359 |
| 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 ... | 1999 | 10516033 |
| infection of five human liver cell lines by dengue-2 virus. | elevated serum transaminase levels of dengue patients indicate the possible impact of dengue virus infection on liver function. to elucidate the action of dengue virus infection in liver cells, an in vitro cell line system was established that mimicked the liver status of diverse clinical patients. briefly, four hepatoma cell lines (ha22t, huh7, hep3b, and plc) and one nonmalignant hepatocyte cell line (chang liver) were included, representing various levels of tumorigenicity and differentiation ... | 2000 | 10686026 |
| dengue epidemic in the state of rio grande do norte, brazil, in 1997. | during 1997 a large dengue epidemic occurred in rio grande do norte, a state in north-east brazil. the co-circulation of dengue virus type 1 and dengue virus type 2 was demonstrated by virus isolation in aedes albopictus clone c6/36 cell-line and by reverse transcriptase-polymerase chain reaction (rt-pcr). igm capture enzyme-linked immunosorbent assay confirmed 52.3% of the 8105 studied cases and dengue antigen was demonstrated by immunohistochemical reaction on hepatocytes from 2 out of 5 fatal ... | 1999 | 10492750 |
| epidemiological and entomological investigation in dengue outbreak area of ahmedabad district. | epidemiological and entomological investigations conducted in seven affected villages of sanand and viramgam talukas of ahmedabad district revealed that all age groups and both the genders were affected. 33.33% blood samples of patients showed seropositivity suggesting dengue infection similarly, dengue virus antigen was detected in 7 females ae. aegypti out of 2 males and 26 females tested by indirect immunofluroscent technique. aedes aegypti population measured by various parameters i.e. premi ... | 2000 | 11129561 |
| dengue haemorrhagic fever in children in the 1996 delhi epidemic. | an epidemic of dengue haemorrhagic fever (dhf) occurred in delhi in 1996. a total of 240 children between the age of 4 months to 13 years of either sex, admitted in one hospital, were evaluated. two hundred and sixteen (90%) children were from delhi. a clinical diagnosis of dengue fever (df) was made in 25 (10%), dengue fever with unusual bleeding (dfb) in 22 (9%), dhf in 80 (33%) and dengue shock syndrome (dss) in 113 (47%) of the children strictly according to the who classification. the age p ... | 1999 | 10492762 |
| purified dengue 2 virus envelope glycoprotein aggregates produced by baculovirus are immunogenic in mice. | the full-length dengue 2 virus envelope glycoprotein (egp) was expressed in insect cells by recombinant (r) baculovirus and found to form multimeric aggregates that were recovered in the void volume of gel filtration columns and by ultracentrifugation. an immunoblot confirmed that regp aggregrates disrupted with sds sample buffer released a monomeric form that migrated with a molecular weight similar to native dengue 2 virus egp on polyacrylamide gels. the regp aggregates reacted strongly with a ... | 2000 | 10775789 |
| efficient trans-complementation of the flavivirus kunjin ns5 protein but not of the ns1 protein requires its coexpression with other components of the viral replicase. | successful trans-complementation of the defective kunjin virus (kun) rna fldgdd with a deletion of the rna polymerase motif gdd in the ns5 gene by using a bhk cell line, repbhk, that continuously produced a functionally active kun replication complex (rc) from replicon rna was recently reported (a. a. khromykh, m. t. kenney, and e. g. westaway, j. virol. 72:7270-7279, 1998). in order to identify whether this complementation of fldgdd rna was provided by the wild-type ns5 protein alone or with th ... | 1999 | 10559344 |
| purified ns2b/ns3 serine protease of dengue virus type 2 exhibits cofactor ns2b dependence for cleavage of substrates with dibasic amino acids in vitro. | dengue virus type 2 ns3, a multifunctional protein, has a serine protease domain (ns3pro) that requires the conserved hydrophilic domain of ns2b for protease activity in cleavage of the polyprotein precursor at sites following two basic amino acids. in this study, we report the expression of the ns2b-ns3pro precursor in escherichia coli as a fusion protein with a histidine tag at the n terminus. the precursor was purified from insoluble inclusion bodies by ni(2+) affinity and gel filtration chro ... | 2000 | 10744671 |
| first outbreak of japanese encephalitis in two villages of dharmapuri district in tamil nadu. | three cases of japanese encephalitis (je) were reported for the first time from two villages in krishnagiri health unit district of tamil nadu during november 1999. two children died and one developed neurological sequelae. a serological survey was conducted in these villages to find out the prevalence of je antibodies among children below 15 yr of age in addition to the epidemiological investigations. | 2000 | 11247195 |
| development of a novel mouse model for dengue virus infection. | in the present study, we established an animal model for dengue virus infection using severe combined immunodeficient mice transplanted with a human hepatocarcinoma cell line (hepg2). at 7-8 weeks after transplantation, the hepg2-grafted mice were infected intraperitoneally with dengue virus type 2 (den-2). a higher titer of the virus was detected in the liver and serum but not in the brain in the early stage of postinfection. when the mice showed paralysis, the highest titer of virus was detect ... | 1999 | 10544083 |
| internal cleavage of hepatitis c virus ns3 protein is dependent on the activity of ns34a protease. | the nonstructural protein ns3 of the hepatitis c virus (hcv) is indispensable for virus replication and a multifunctional enzyme that contains three catalytic activities such as serine protease, helicase, and ntpase. here, we demonstrated that the internal cleavage of the hcv ns3 protein occurs in various mammalian cells such as hepg2, cos-7, and nih3t3. as is observed for the internal cleavage mechanism of the ns3 protein of dengue virus 2, the internal processing of hcv ns3 protein was catalyz ... | 2000 | 10683335 |
| quantitative detection of dengue 2 virus using fluorogenic rt-pcr based on 3'-noncoding sequence. | a fluorescent dna probe (dv2.p1) specific to the conserved distal 3'-noncoding region (nucleotides 10653-10678) of dengue 2 virus and a pair of flanking primers (dv2.l1 and dv2.u2) were designed to formulate a dengue 2-specific fluorogenic polymerase chain reaction (pcr). in addition, dv2.l1 was also used as a reverse transcription (rt) primer to generate superior cdna from dengue viral rna. optimal assay conditions with zero background were established to detect low levels of dengue 2 virus fro ... | 2000 | 10713370 |
| live attenuated tetravalent dengue vaccine. | the development of a live attenuated tetravalent dengue vaccine is currently the best strategy to obtain a vaccine against dengue viruses. the mahidol university group developed candidate live attenuated vaccines by attenuation through serial passages in certified primary cell cultures. dengue serotype 1, 2 and 4 viruses were developed in primary dog kidney cells, whereas dengue serotype 3 was serially passaged in primary african green monkey kidney cells. tissue culture passaged strain viruses ... | 2000 | 10821973 |
| failure of secondary infection with american genotype dengue 2 to cause dengue haemorrhagic fever. | population-based epidemiological studies have shown that infection with dengue type 2 (den-2) virus in individuals previously infected with a different serotype of the virus is a major risk factor for dengue haemorrhagic fever and dengue shock syndrome. however, the western hemisphere was spared epidemics of these two syndromes, until the introduction of a southeast asian den-2 genotype. possibly american den-2 genotype strains lacked properties necessary to cause severe disease. we report on a ... | 1999 | 10543670 |
| 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 |
| human dengue antibodies against structural and nonstructural proteins. | antibodies against dengue virus type 2 and 4 proteins in acute-phase sera of 10 primary and 10 secondary dengue fever and dengue hemorrhagic fever patients were studied by western blotting. in the first group the immune response was barely detectable, while in the second group more proteins were detected, with a very strong reaction. anti-ns1 and -ns3 antibodies were detected mainly in secondary cases. anti-e, -ns3, and -ns5 antibodies were detected in a high number of cases. the possibility of ... | 2000 | 10973471 |
| involvement of oxidative stress, nf-il-6, and rantes expression in dengue-2-virus-infected human liver cells. | the liver has been suspected to be one of the major targets of dengue virus infection. here, we detected increasing secretion of the chemokine rantes (regulated upon activation, normal t cell expressed and secreted), which functions to recruit the immune cells, in dengue-virus-infected liver cells and patients. three luciferase reporter genes with various deletions at the 5'-end of the rantes promoter were constructed to explore the rantes activation mechanism in human liver cells. the reporter ... | 2000 | 11022000 |
| probing the interaction of dengue virus envelope protein with heparin: assessment of glycosaminoglycan-derived inhibitors. | a structure-activity relationship study was carried out to facilitate development of inhibitors of dengue virus infectivity. previous studies demonstrated that a highly charged heparan sulfate, a heparin-like glycosaminoglycan found on the cell surface, serves as a receptor for dengue virus by binding to its envelope protein. interventions that disrupt this binding effectively inhibit infectivity. a competitive binding assay was developed to screen polyanionic compounds for activity in preventin ... | 2001 | 11405655 |
| 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 |
| molecular evolution, distribution and genetic relationship among the dengue 2 viruses isolated from different clinical severity. | twenty-two strains of dengue 2 virus, isolated in china, latin america, new guinea and thailand were subjected to phylogenetic analysis. the upgma analysis was carried out on each gene region of dengue virus and demonstrated that outcome from most of the gene regions showed similar results except those from ns4b and yutr with very short nucleotide length. among ten regions examined, the results from e gene documented the geographical differences of the virus strains most clearly and all the amer ... | 2000 | 11127324 |
| alteration of virus entry mode: a neutralisation mechanism for dengue-2 virus. | polyclonal antibodies derived from dengue virus immune sera and 3h5 monoclonal antibody showed potent neutralisation effect on dengue-2 virus in the plaque reduction neutralisation assay. this study demonstrated that antibodies present in immune human sera and 3h5 monoclonal antibody neutralised dengue-2 virus by altering the virus entry pathway into cells. in the presence of neutralising antibodies, dengue-2 virus was endocytosed by llc-mk2 cells. the endocytosis process involved ruffling of an ... | 2000 | 11055247 |
| study of biologic attributes of cuban dengue 2 virus after serial passage in primary dog kidney cells. | the serial passage of dengue viruses in primary dog kidney (pdk) cells has resulted in selection of attenuated viruses. however, the molecular changes responsible for loss of virulence are not well characterized. this article describes the isolation and biologic attributes of one dengue 2 virulent strain as a first step to allow the study of determinants of virulence at the molecular level. | 2001 | 11285157 |
| dengue virus and insecticide susceptibility status of aedes aegypti mosquitoes from belagola village, mandya district, karnataka state: during and post-epidemic investigations. | aedes aegypti mosquitoes collected during and after dengue virus epidemic season were exposed to diagnostic dosages of insecticides. mosquitoes collected during the epidemic showed resistance to ddt only, while mosquitoes collected after the control measures showed tolerance to malathion and low resistance to ddt. since there was no indication of malathion resistance in the mosquitoes collected during the epidemic, the second batch was subjected to malathion selection pressure for 8 generations ... | 2000 | 11668935 |
| 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 |
| horizontal and vertical transmission of dengue virus type 2 in highly and lowly susceptible strains of aedes aegypti mosquitoes. | isofemale lines of aedes aegypti mosquitoes highly and lowly susceptible to dengue type 2 (den-2) virus (den(h) and den(l), respectively) were established by oral feeding and individual rearing. the susceptibility at f13 generation was found to be 61% and 25% for the den(h) and den(l) line, respectively. the virus-infected mosquito females were allowed to probe on bovine albumin phosphate saline ph 7.2 (baps) through membrane feeders. the presence of virus in the probed baps was determined eithe ... | 2001 | 11719984 |
| detection of anti-arboviral immunoglobulin g by using a monoclonal antibody-based capture enzyme-linked immunosorbent assay. | monoclonal antibody (mab)-based capture enzyme-linked immunosorbent assays (elisas) for the detection of anti-arboviral immunoglobulin g (igg elisas) were developed for a comprehensive array of medically important arboviruses from the alphavirus, flavivirus, and bunyavirus genera. tests were optimized and standardized so that maximum homology could be maintained among working parameters for the different viral agents, enabling a wide range of viruses to be easily tested for at one time. mabs wer ... | 2000 | 10790108 |
| antibody responses of dengue fever patients to dengue 2 (new guinea c strain) viral proteins. | the present study was undertaken to investigate the antibody responses of dengue fever (df) patients to specific dengue virus proteins. partially purified dengue 2 new guinea c (ngc) strain virus was used as antigen. under the present experimental protocols, it was observed that almost all df patients' sera had detectable presence of antibodies which recognize the dengue 2 envelope (e) protein. the convalescent-phase sera especially had significant detectable igg, igm and ige against the protein ... | 1997 | 10879241 |
| cellular proteins bind to the 3' and 5' untranslated regions of dengue 2 virus genome. | in vitro generated cloned full length dengue 2 virus untranslated regions (utrs) were used in rna gel mobility shift assays to examine cellular factors binding to the virus genomes. cellular factors in lysates of vero (monkey) and c6/36 (mosquito) cells bound specifically and non-specifically to the dengue 2 virus 3' utr. non-specific interaction with the 5' utr, resulting in formation of at least 4 band shift complexes was noted with lysate of the c6/36 cells only. pre-treating the cell lysates ... | 1998 | 10879258 |
| isolation and partial characterization of dengue virus type 2 and 4 strains from dengue fever and dengue haemorrhagic fever patients from mindanao, republic of the philippines. | isolation of dengue virus from dengue fever and dengue haemorrhagic fever cases from mindanao, republic of the philippines. | 2000 | 10886794 |
| infection of dengue 2 virus strains isolated from patients exhibiting different disease severities to human peripheral blood leukocytes and production of cytokines in the infected culture supernatant. | three strains of type 2 dengue virus (dv-2), which had been isolated from patients exhibiting different disease severity, were inoculated to primary culture of human peripheral blood leukocytes from 3 healthy donors. the percentage of dengue antigen positive cells was highest for the strain isolated from a case of dengue shock syndrome, followed by the strain isolated from a case of dengue hemorrhagic fever, and lowest for the strain isolated from a mild case of dengue fever (df). generally, sim ... | 1999 | 10928367 |
| epidemiologic studies on dengue in santiago de cuba, 1997. | a small, isolated outbreak of dengue hemorrhagic fever/dengue shock syndrome (dhf/dss) due to dengue virus type 2 (den-2) was documented in santiago de cuba on the island of cuba beginning in january 1997. there were 205 dhf/dss cases, all in persons older than age 15 years. all but three had evidence of a prior dengue infection, with the only known opportunity being the islandwide dengue virus type 1 (den-1) epidemic of 1977-1979. virtually complete clinical and laboratory surveillance of overt ... | 2000 | 11085389 |
| [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 |
| invited commentary: dengue lessons from cuba. | an 18-year interval between a dengue virus type 1 outbreak in 1977-1979 and a dengue virus type 2 outbreak in 1997 in santiago de cuba, cuba, provided a unique opportunity to evaluate risk factors for dengue disease. all patients with symptomatic dengue, including 205 cases of dengue hemorrhagic fever and 12 deaths, were adults born before the dengue virus type 1 epidemic, and nearly all (98%) experienced secondary dengue virus infections. in contrast, almost all of those who seroconverted witho ... | 2000 | 11085390 |
| manifestation of thrombocytopenia in dengue-2-virus-infected mice. | dengue virus infection causes dengue fever, dengue haemorrhagic fever and dengue shock syndrome. no animal model is available that mimics these clinical manifestations. in this study, the establishment is reported of a murine model for dengue virus infection that resembles the thrombocytopenia manifestation. dengue-2 virus (dengue virus type 2) can infect murine cells either in vitro (primary cell culture) or in vivo. viraemia detected by rt-pcr was found transiently at 2 days after intravenous ... | 2000 | 10950974 |
| comparison of rapid centrifugation assay with conventional tissue culture method for isolation of dengue 2 virus in c6/36-ht cells. | a rapid centrifugation assay was compared with conventional tube cell culture for dengue virus isolation in both sera and autopsy samples from dengue and dengue hemorrhagic fever/dengue shock syndrome fatal cases. the rapid centrifugation assay allowed isolation of virus from 16.6% more samples than the conventional method, and it shortened the time for dengue virus detection. finally, it allowed the isolation of dengue 2 virus in 42.8% of tissue samples from five fatal cases. our results sugges ... | 2000 | 10970418 |
| recombinant plasmid expressing a truncated dengue-2 virus e protein without co-expression of prm protein induces partial protection in mice. | a nucleic acid vaccine candidate against dengue-2 virus was constructed to express a truncated dengue-2 e glycoprotein without concomitant expression of prm. the truncated e protein was properly expressed even in the absence of prm. mice inoculated intramuscularly with the recombinant plasmid containing 94% of the e gene did not respond with anti-dengue antibodies, cellular proliferation, or synthesis of cytokines by their lymphoid cells when stimulated with purified dengue-2 virus. however, pro ... | 2000 | 11090717 |
| 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 |
| 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 |
| 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 |
| a dengue shock patient with negative serology and polymerase chain reaction (pcr) tests. | a 6-month-old thai girl presented with clinical manifestations of dengue shock syndrome (dss) with encephalopathy and urinary tract infection. serology and pcr tests were negative whereas dengue virus type 2 was isolated. in cases of highly suspected dengue infections, viral isolation should be done even when serological and pcr tests are negative. | 2000 | 11127323 |
| 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 |
| cytotoxic factor-autoantibodies: possible role in the pathogenesis of dengue haemorrhagic fever. | during dengue virus infection a unique cytokine, cytotoxic factor (hcf), is produced that is pathogenesis-related and plays a key role in the development of dengue haemorrhagic fever (dhf). however, what regulates the adverse effects of hcf is not known. we have previously shown that anti-hcf antibodies raised in mice, neutralise the pathogenic effects of hcf. in this study we have investigated the presence and levels of hcf-autoantibodies in sera of patients with various severity of dengue illn ... | 2001 | 11335136 |
| the dengue and dengue hemorrhagic fever epidemic in puerto rico, 1994-1995. | from june 1, 1994 to may 31, 1995 a total of 24,700 cases of dengue (7.01/1,000 population) were reported to the laboratory-based surveillance system in puerto rico (1991-1994, annual average: 2.55/1,000). dengue virus 2 predominated. the earliest indicator of epidemic activity was the virus isolation rate in may 1994 (14.0% versus 5.7% average). the male-to-female ratio among cases was 1:1.1; 65.4% were younger than 30 years (the 10 to 19 year age group had the highest incidence, 11.8/1,000). a ... | 2001 | 11425166 |
| amino acid and phenotypic changes in dengue 2 virus associated with escape from neutralisation by igm antibody. | two dengue 2-specific igm monoclonal antibodies (mab) recognised spatially unrelated epitopes on the envelope (e) protein of dengue 2 virus, which were also recognised by serum from 20 and 50%, respectively, of patients with a primary dengue 2 infection. dengue 2 virus populations escaping neutralisation by mab 6b2 (representing the majority population of dengue 2-specific igm mabs ) had a deduced amino acid change (g-s) in the pre-membrane (prm) protein at position 15 and a second in the e prot ... | 2001 | 11536239 |
| 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 |
| use of nucleotide sequencing of the genomic cdna fragments of the capsid/premembrane junction region for molecular epidemiology of dengue type 2 viruses. | the recent emergence of dengue hemorrhagic fever/dengue shock syndrome (dhf/ dss) in india has been a source of concern. in the present study a quantitative comparison of 406 nucleotide long sequence from the capsid-premembrane junction region (c-prm) of 9 dengue virus type 2 (den-2) isolates from delhi with 10 den-2 isolates from diverse geographic areas provided sufficient information for estimating genetic relationships. the data indicated that the 1996 epidemic of dhf in delhi was caused by ... | 2001 | 11556585 |
| 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 |
| 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 |
| mutagenesis of the dengue virus type 2 ns3 proteinase and the production of growth-restricted virus. | the n-terminal one-third of the ns3 protein of dengue virus type 2 (den-2) complexes with co-factor ns2b to form an active serine proteinase which cleaves the viral polyprotein. to identify sites within ns3 that may interact with ns2b, seven regions within the ns3 proteinase outside the conserved flavivirus enzyme motifs were mutated by alanine replacement. five sites contained clusters of charged residues and were hydrophilic. two sites were hydrophobic and highly conserved among flaviviruses. ... | 2001 | 11413376 |
| 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 |
| [outbreak of dengue-2 virus in salta, argentina, 1988]. | dengue (den) reemergence was first detected in salta, argentina, in 1997. it was confirmed by serology and pcr that den-2 virus was responsible for sporadic cases and indigenous transmission. a laboratory-based surveillance system allowed the detection of an outbreak in salta several months later. in total, 378 den cases were laboratory diagnosed out of 646 (58%) studied. the cases were distributed in 10 localities of the province between january 3rd and may 31st, 1998. one den-2 viral isolation ... | 2000 | 11436695 |
| mutagenesis of the dengue virus type 2 ns3 protein within and outside helicase motifs: effects on enzyme activity and virus replication. | the protein ns3 of dengue virus type 2 (den-2) is the second largest nonstructural protein specified by the virus and is known to possess multiple enzymatic activities, including a serine proteinase located in the n-terminal region and an ntpase-helicase in the remaining 70% of the protein. the latter region has seven conserved helicase motifs found in all members of the family flaviviridae. den-2 ns3 lacking the proteinase region was synthesized as a fusion protein with glutathione s-transferas ... | 2001 | 11559795 |
| 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 |
| replication of dengue virus type 2 in human monocyte-derived macrophages: comparisons of isolates and recombinant viruses with substitutions at amino acid 390 in the envelope glycoprotein. | the severity of dengue virus infection ranges from mild fever to dengue hemorrhagic fever and shock syndrome. the association of disease severity with virus replication in monocyte-derived macrophages (mdms) was examined for dengue virus type 2 (den-2) isolates from asia or america. additionally, we constructed den-2 recombinant viruses with substitutions at residue 390 in the envelope glycoprotein (e390) because this residue is linked with the region of virus origin. comparisons of virus yields ... | 2001 | 11716094 |
| population structure of aedes albopictus from la réunion island (indian ocean) with respect to susceptibility to a dengue virus. | ten f1 aedes albopictus samples collected from réunion island in the indian ocean were tested for oral susceptibility to dengue 2 virus and 20 were analysed for genetic polymorphism by starch gel electrophoresis. data from infection rates defined two distinct geographical areas: east coast vs. west coast. genetic differentiation was found to be dependent on ecological factors and the biological characteristics of ae. albopictus. these results have implications for the vector ecology and pattern ... | 2001 | 11737274 |
| 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 |
| 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 |
| [dengue virus-specific antigen lymphoproliferation assay with human t cells]. | papers dealing with the study of the immune response to dengue virus infection and with the role it may play in the pathogenesis of dengue hemorrhaghic fever are increasingly important. the memory human t cell response in individuals with history of dengue infection during the cuban epidemic was studied in this paper for a further evaluation of the antigenicity of viral proteins. to this end, mononuclear cells of peripheral blood from individuals immune to dengue and from a group of control subj ... | 2000 | 11826523 |
| [biological behavior of 3 strains of the dengue-2 virus in 2 cell lines of mosquitoes]. | strains a-15 (isolated in cuba, 1981), jamaica (isolated in jamaica, 1981) and nueva guinea "c" (standard) from dengue-2 virus were compared according to the time of appearance of the cytopathic effect (cpe), to the time of appearance of specific fluorescence and to the kynetics of viral multiplication on being innoculated in the cell lines ap-61 (aedes pseudoscutellaris) and c6/36 ht (aedes albopictus). the results showed that the cpe of highest intensity and earliest appearance was for a-15, f ... | 2000 | 11826526 |
| 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 |
| 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 |