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chemically-induced temperature sensitive mutants of dengue virus type 2. i. isolation and partial characterization.temperature sensitive (ts) mutants of dengue virus type 2 (den-2, th-36 isolate) were induced by replication in primary hamster kidney cells treated with 5-azacytidine. seven ts mutants were obtained from 138 clones isolated by an immunofluorescent cloning technique. of these 7 ts mutants, 5 were sufficiently stable to permit partial characterization. complementation was detected at very low but statistically significant levels between some ts mutants at 40 degrees c. viral double-stranded rna p ...197656929
chemically induced temperature-sensitive mutants of dengue virus type 2: comparison of temperature sensitivity in vitro with infectivity suckling mice, hamsters, and rhesus monkeys.a series of temperature-sensitive (ts) mutants of dengue virus type 2 (den-2, th-36 isolate) were induced by treatment with 5-azacytidine. these mutants and parental viruses were compared for the ts trait and/or attenuation in four systems: primary hamster kidney cells, suckling mice, golden syrian hamsters, and rhesus monkeys. seven clones judged to possess the ts trait in virto demonstrated a variety of patterns in vivo. on initial isolation, five of seven ts mutants exhibited reduced mouse le ...197657925
dengue viruses and mononuclear phagocytes. ii. identity of blood and tissue leukocytes supporting in vitro infection.studies were made on the identity of human and monkey mononuclear leukocytes permissive to antibody-enhanced dengue 2 virus (d2v) infection. in cultures of peripheral blood leukocytes (pbl) inoculated immediately after separation, it was concluded that only mononuclear phagocytes support dengue infection. this is based upon observations that d2v-permissive cells were resistant to 1,200 rads, were both plastic adherent and nonadherent, were removed when passed through nylon wool columns in 10 per ...1977195000
phytohemagglutinin enhancement of dengue-2 virus replication in nonimmune rhesus monkey peripheral blood leukocytes.phytohemagglutinin treatment of peripheral blood leukocytes from dengue nonimmune monkeys enhanced dengue-2 virus replication. enhancement was due primarily to an increase in the number of infected cells. destruction of mononuclear phagocytes with silica did not significantly inhibit virus replication in phytohemagglutinin-treated cultures. pokeweed mitogen, concanavalin a, and streptolysin o stimulated increased deoxyribonucleic acid synthesis in monkey leukocytes but did not enhance virus repl ...1978203535
replication of dengue and junin viruses in cultured rabbit and human endothelial cells.the flavivirus dengue and the arenavirus junin are both associated with a hemorrhagic shock syndrome in man. we have demonstrated the replication of these viruses in vitro in both rabbit and human endothelial cells by viral titers and immunofluorescent antibody studies. rabbit endothelium established in continuous culture was derived from vena cava, while human cells in primary culture were derived from umbilical veins. in rabbit endothelium, dengue-2 virus passaged through monkey kidney monolay ...1978208980
dengue viruses and mononuclear phagocytes. i. infection enhancement by non-neutralizing antibody.cultured mononuclear peripheral blood leukocytes (pbl) from nonimmune human beings and monkeys are nonpermissive to dengue 2 virus (d2v) infection at multiplicities of infection of 0.001-0.1, but become permissive when non-neutralizing dengue antibody is added to medium. d2v infection occurred in pbl prepared from anti-coagulated but not from defibrinated plasma. infection enhancement was produced by multiple lots of heterotypic anti-dengue raised in several mammalian species. homotypic anti-den ...1977406347
variation in susceptibility to oral infection with dengue viruses among geographic strains of aedes aegypti.the comparative susceptibility of 13 geographic strains of aedes aegypti to oral infection with dengue viruses was studied by feeding the mosquitoes on a virus-erythrocyte-sugar suspension. significant variation in susceptibility to four dengue serotypes was observed among the geographic strains tested. mosquito strains which were more susceptible to one serotype were also more susceptible to the other serotypes, suggesting that the factors controlling susceptibility were the same for all types. ...1979507282
effect of immune status on dengue 2 virus replication in cultured leukocytes from infants and children.cord blood leukocytes from neonates with maternal dengue antibody supported dengue 2 virus replication in vitro; those from neonates without maternal antibody did not. cord bloods of infants born to dengue-immune mothers contained a potent enhancing factor which gradually decayed with age and which was absent from neonates born to nonimmune mothers. permissiveness of cultures of washed peripheral blood leukocytes from infants with maternal antibody declined steadily with increasing age in parall ...1979572345
replication of dengue-2 virus in aedes albopictus mosquitoes. an electron microscopic study.sequential electronmicroscopic studies of aedes albopictus mosquitoes infected with dengue-2 virus showed replication of virus particles and vesicular structures confined to cells having an active, rough, endoplasmic reticulum. small granules not found on the surface of virions produced in mammalian cells were seen on the envelopes of the virus particles. there was no evidence of nuclear involvement as described in infected mouse neurones, and there was no apparent impairment of cellular functio ...1977596516
ultrastructural studies on dengue virus infection of human lymphoblasts.ultrastructural studies of dengue-2 virus-infected lymphoblastoid raji cells showed that the virus induced an increase in the size of the rough endoplasmic reticula (rer) and that the replication of the virus was confined to the cisternae of these rer. the proliferating rer formed cytoplasmic inclusions that could be seen by light microscopy. this observation could be used as evidence of a cytopathogenic effect of dengue virus on infected rajii cells in routine cultures. accumulation of virions ...1978669791
isolation of a temperature-sensitive dengue-2 virus under conditions suitable for vaccine development.dengue virus, type 2, in viremic human sera and after passage in cell cultures produces mixtures of small and large plaques when assayed in llc-mk2 cells. clones of dengue virus type 2 obtained by plaque selection in primary green monkey kidney cell cultures were tested for temperature sensitivity in vitro and for virulence by intracerebral inoculation of suckling mice. sublines of a small-plaque clone were found to have lower nonpermissive temperatures than the parent virus by both plaque forma ...1976977127
dengue virus replication enhancement in peripheral blood leukocytes from immune human beings.dengue 2 virus replication in peripheral blood leukocyte cultures from 10 of 13 asian or polynesian subjects with actively acquired dengue immunity and two of three infants with passively acquired dengue antibody. only 2 of 11 cultures from nonimmune infants or children supported viral replication. this study establishes a parallel in the biological behavior of human and simian pbl with respect to the immunological dependence of dengue virus replication in vitro. elucidation of the mechanism (or ...19761250839
mapping of a region of dengue virus type-2 glycoprotein required for binding by a neutralizing monoclonal antibody.envelope glycoprotein e of flaviviruses is exposed at the surface of the virion, and is responsible for eliciting a neutralizing antibody (ab) response, as well as protective immunity in the host. in this report, we describe a method for the fine mapping of a linear sequence of the e protein of dengue virus type-2 (den-2), recognized by a type-specific and neutralizing monoclonal ab (mab), 3h5. first, an escherichia coli expression vector containing a heat-inducible lambda pl promoter was used t ...19921634111
detection of cattle infected with bovine viral diarrhea virus using nucleic acid hybridization.a ribonucleic acid (rna) hybridization assay to identify cattle infected by bovine viral diarrhea virus (bvdv) is described. the rna probe was derived from the coding region at the 3' end of the genome of the nadl strain of bvdv. total rna from infected cell cultures or peripheral blood leukocytes from suspect animals was extracted and applied to nylon membranes with a slot blot apparatus. peripheral blood leukocytes were tested concurrently for bvdv by virus isolation. the results of hybridizat ...19911645592
obligatory role of ca2+ in the cytotoxic activity of dengue virus-induced cytotoxin.the role of calcium ions (ca2+) in the cytotoxic activity of the dengue type 2 virus (dv)-induced macrophage (m phi) cytotoxin (cf2) was investigated in the present study. the findings show that cf2 prepared in ca(2+)-free medium had no cytotoxic activity on normal mouse spleen cells suspended in ca(2+)-free medium but killed the cells suspended in the medium with ca2+. substitution with calcium chloride restored the cytotoxic activity of cf2 the optimal dose being 10(-4) m concentration. cf2 in ...19911653589
detection of stable secondary structure at the 3' terminus of dengue virus type 2 rna.the 3'-terminal sequences of flavivirus genomes within approx. 100 nucleotides (nt) have been suggested to have a highly conserved secondary structure, as based on the known nt sequence data and free-energy calculations using computer programs. to test the existence of a secondary structure in solution, we devised a strategy to generate truncated rna molecules from about 0.3-1.4 kb in length, having the same polarity and nt sequence as dengue virus type 2 (den-2) rna (new guinea-c strain). when ...19911660836
dengue-2 virus isolation from humans during an epizootic in southeastern senegal in november, 1990. 19921594790
construction of intertypic chimeric dengue viruses by substitution of structural protein genes.dengue virus contains an 11-kilobase positive-strand rna genome that codes for, in one open reading frame, three structural proteins (capsid, premembrane, and envelope), followed by seven nonstructural proteins. the structural protein genes of a full-length cdna clone of type 4 dengue virus were replaced with the corresponding genes of dengue 1 or dengue 2 to create intertypic chimeric cdna. the rna transcripts made from these templates were infectious when transfected into permissive cells in c ...19911682924
dengue haemorrhagic fever in children in delhi.an epidemic of dengue haemorrhagic fever occurred in delhi during 1988. a total of 21 paediatric patients with dengue haemorrhagic fever/dengue shock syndrome were evaluated from september to november 1988. all the patients had fever, restlessness, ecchymotic spots and ascites. pleural effusion occurred in 19 patients (90%), and 18 (86%) exhibited each of the following: vomiting, thrombocytopenia, and haemoconcentration. hepatomegaly was observed in 15 patients (71%) and splenomegaly in three (1 ...19921568274
replication of dengue virus type 2, brazilian strain, in mosquito cell cultures. 19911688183
breakdown of the blood-brain barrier during dengue virus infection of mice.a breakdown of the blood-brain barrier occurred in mice inoculated intracerebrally (i.c.) or intraperitoneally (i.p.) with dengue virus type 2 (den2). this resulted in leakage of protein-bound evans blue dye and 51cr-labelled erythrocytes into the brain tissue. the leakage increased with time after infection and coincided with an increase of a den2-induced cytokine, the cytotoxic factor (cf), in the spleens of such mice. the titres of virus in the brain increased exponentially in i.c. inoculated ...19911707947
geographical clusters of dengue virus type 2 isolates based on analysis of infected cell rna by the chemical cleavage at mismatch method.genetic variation in 12 strains of dengue virus type 2, isolated from several epidemic areas in different years, was studied by chemical cleavage at mismatched cytosine in dna:rna heteroduplexes. end-labelled cdna probes derived from the e and ns2a genes of the new guinea c strain were hybridized to total rna extracted from cells infected by individual isolates. following modification of mismatched cytosine by hydroxylamine and nucleic acid strand cleavage by piperidine, the resulting fragments ...19921452634
processing and localization of dengue virus type 2 polyprotein precursor ns3-ns4a-ns4b-ns5.processing of dengue virus type 2 polyprotein precursor ns3-ns4a-ns4b-ns5 could be mediated by the catalytically active ns3 protease domain and ns2b in trans at the dibasic sites ns3-ns4a and ns4b-ns5. subcellular localization of the unprocessed precursor ns3-ns4a-ns4b-ns5 showed that it was confined to a distinct subcellular organelle in the cytoplasm, which was distinct from the distribution of the mature ns5.19921433530
amplification of dengue 2 virus ribonucleic acid sequence using the polymerase chain reaction.the polymerase chain reaction (pcr) has been adapted to the amplification of dengue type 2 virus (den2) nucleic acid sequences. a pair of 20-mer oligonucleotides were designed and synthesized based on conserved sequence blocks of den2 strains isolated from different geographical areas. rna samples were prepared from two den2 strains, prototype new guinea c (ngc) and local isolate hainan 98 (hn98). the reverse transcription step was performed for cdna synthesis before the standard pcr procedures. ...19921381844
use of recombinant fusion proteins and monoclonal antibodies to define linear and discontinuous antigenic sites on the dengue virus envelope glycoprotein.sixteen overlapping fragments of the dengue-2 virus envelope (e) protein, expressed as trpe-e fusion products in escherichia coli, were used to map the epitopes defined by a panel of 20 monoclonal antibodies (mabs) by immunoblotting. using this technique, the amino acid sequence of six antigenic domains on the e protein was characterized. nonneutralizing mabs were found to define either linear-specific, subcomplex-specific (amino acids 22-58), and complex-specific (amino acids 304-332) epitopes ...19921372140
ns 1 gene sequences from eight dengue-2 viruses and their evolutionary relationships with other dengue-2 viruses.the nucleotide sequences of the ns 1 genes from five thai and three sri lankan dengue-2 viruses were determined by sequencing the viral rna using synthetic oligonucleotide primers. the results were shown to be similar to four published dengue-2 ns 1 sequences and the classification of these genes was compared with the one obtained for the envelope genes of the same viruses. the classification was similar and showed that the thai isolates could be divided into two separate groups and that the sri ...19911829885
production of dimer-specific and dengue virus group cross-reactive mouse monoclonal antibodies to the dengue 2 virus non-structural glycoprotein ns1.a panel of mouse monoclonal antibodies (mabs) raised against the non-structural glycoprotein ns1 of dengue 2 virus (pr159) was studied for cross-reactivity with the ns1 protein of other dengue virus serotypes and other members of the flaviviridae using immunoblotting. most of the 35 anti-ns1 mabs were found to be specific for dengue 2 virus ns1 (some of which were specific for the native, dimeric form of this protein), but others were found to cross-react within the dengue virus group. this latt ...19911849979
dengue 2 virus enhancement in asthmatic and non asthmatic individual.during the 1981 dengue hemorrhagic fever/dengue shock syndrome (dhf/dss) cuban epidemic, bronchial asthma (ba) was frequently found as a personal or family antecedent in dengue hemorrhagic fever patients. considering that antibody dependent enhancement (ade) plays an important role in the etiopathogenic mechanism of dhf/dss, we decide to study the dengue 2 virus (d2v) capability of replication in peripheral blood leukocytes (pbl) from asthmatic patients and healthy persons. in 90% of asthmatic p ...19921343671
envelope protein sequences of dengue virus isolates th-36 and th-sman, and identification of a type-specific genetic marker for dengue and tick-borne flaviviruses.complementary dnas were synthesized from the envelope protein genes of two isolates of dengue virus (th-36 and th-sman, previously suggested as possible dengue virus type 5 and dengue virus type 6 respectively) and amplified by the polymerase chain reaction using sense and antisense primers designed from conserved dengue virus gene sequences. the amplified cdna clones were sequenced in both directions by double-stranded dideoxynucleotide sequencing. alignment with published dengue virus sequence ...19921339466
comparison of a dengue-2 virus and its candidate vaccine derivative: sequence relationships with the flaviviruses and other viruses.a comparison of the sequence of the dengue-2 16681 virus with that of the candidate vaccine strain (16681-pdk53) derived from it identified 53 of the 10,723 nucleotides which differed between the strains. nucleotide changes occurred in genes coding for all virion and nonvirion proteins, and in the 5' and 3' untranslated regions. twenty-seven of the nucleotide changes resulted in amino acid alterations. the greatest amino acid sequence differences in the virion proteins occurred in prm (2.20%; 2/ ...19921312269
nuclear localization of dengue 2 virus core protein detected with monoclonal antibodies.anti-dengue 2 virus core protein monoclonal antibodies (mabs) reacted with antigens in the cytoplasm and in, or on, the nucleus of dengue 2 and dengue 4, but not dengue 1, dengue 3, kunjin or murray valley encephalitis virus-infected cells. these mabs also reacted with the core protein from dengue 1, 2 and 4 virions in western blots. the antigens detected by these mabs could not be detected in uninfected or heat-shocked cells, but were first detected in infected cells approximately 32 h post-inf ...19921279106
variation among geographic strains of aedes albopictus in susceptibility to infection with dengue viruses.the comparative susceptibility to dengue virus infection of 13 geographic strains of aedes albopictus was studied by feeding the mosquitoes on a virus-erythrocyte-sugar suspension. significant variation in susceptibility for each of the four dengue serotypes was observed among the geographic strains. mosquito strains which were more susceptible to infection with one dengue serotype also were more susceptible to the other dengue serotypes. there was a direct relationship between the amount of vir ...19761259091
replication of dengue-2 virus in cultured human lymphoblastoid cells and subpopulations of human peripheral leukocytes.we studied the susceptibility of four human lymphoblastoid cell lines (hcl) and of subpopulations of circulating peripheral human leukocytes to dengue-2 virus infection. hcl with b cell characteristics (raji, wil 2wt, 8866), b-type peripheral lymphocytes, and macrophages were productively infected by dengue-2 virus. in contrast, an hcl with t cell characteristics (molt-4), t type peripheral lymphocytes, and polymorphonuclear (pmn) cells did not become infected and replicate dengue-2 virus. pmn c ...19761085314
endemic dengue virus infection in hispaniola. i. haiti.antibodies to group b arbovirus were common among coastal populations in the haitian part of the caribbean island of hispaniola. antibodies were present in 43% of children one to five years old; prevalence in older persons increased with age. in nine asymptomatic persons serodiagnostic changes indicative of group b arbovirus were detected during six of twelve consecutive months. in port cities where antibodies were common in children, aedes aegypti indices of 50%-70% were observed; in contrast, ...1976993618
isolation of dengue virus type 2 in rio de janeiro. 19902087163
immunization of mice with recombinant vaccinia virus expressing authentic dengue virus nonstructural protein ns1 protects against lethal dengue virus encephalitis.the protective immunity conferred by a set of recombinant vaccinia viruses containing the entire coding sequence of dengue virus type 4 nonstructural glycoprotein ns1 plus various flanking sequences was evaluated by using a mouse encephalitis model. mice immunized with recombinant vns1-ns2a, which expresses authentic ns1, were solidly protected against intracerebral dengue virus challenge. however, mice immunized with recombinants vns1-15%ns2a and vrsvg/ns1-15%ns2a, which express aberrant forms ...19902143542
in vitro processing of dengue virus type 2 nonstructural proteins ns2a, ns2b, and ns3.we have tested the hypothesis that the flavivirus nonstructural protein ns3 is a viral proteinase that generates the termini of several nonstructural proteins by using an efficient in vitro expression system and monospecific antisera directed against the nonstructural proteins ns2b and ns3. a series of cdna constructs was transcribed by using t7 rna polymerase, and the rna was translated in reticulocyte lysates. the resulting protein patterns indicated that proteolytic processing occurred in vit ...19902143543
the influence of arboviral infection on the susceptibility of cultured cells to immune injury in vitro.the susceptibility of llc-mk2 monkey kidney cells to antivirus (antibodies versus viral antigens in the plasma membrane) and anticell (antibodies versus plasma membrane antigens) immune cytolysis in vitro was observed during the course of 100 continuous subcultures of these cells. in that period, llc-mk2 cells infected with the group b arboviruses, japanese encephalitis virus and dengue 2 virus, became progressively refractory to the complement-dependent antivirus immune cytolysis as measured ...1975808137
placental passage of antibodies to dengue virus in persons living in a region of hyperendemic dengue virus infection.maternal and umbilical cord levels of antibodies to dengue 2 and 3 viruses were compared in 54 matched pairs of specimens from subjects in the dominican republic. dengue infection appeared to be hyperendemic; pregnant women experienced a 6% weekly infection rate. titers of antibody to dengue 2 and 3 viruses were considerably higher in cord sera than in maternal sera (p smaller than 0.001 and p smaller 0.01, respectively), especially when maternal levels were low. when maternal and cord sera were ...1975805190
influence of cell type and virus upon virus-specific immune cytolysis.immune cytolysis was measured by release of absorbed radioactive chromium from infected cells that were incubated with antiviral antibody and complement. the presence of virus-specific antigens detected in this manner on the surface of several types of cells infected with japanese encephalitis (je) virus did not correlate in each instance with the maturation of infectious virus. je-infected llc-mk-2 and vero cells could not be lysed until long after the first appearance of released virus, and th ...1975803470
studies on the susceptibility of a large urban population of aedes aegypti to infection with dengue viruses.a large urban population of aedes aegypti in jakarta, indonesia was studied for one year to determine whether it was homogeneous in terms of susceptibility to dengue viruses and whether seasonal changes in susceptibility to dengue viruses occurred. mosquitoes from several districts in jakarta showed a low but homogeneous susceptibility to dengue 2 virus from november 1975 to april 1976. in june 1976, increased susceptibility to dengue 2 virus was observed among some of the subpopulations of ae. ...1978751215
antibodies to dengue 2 virus e-glycoprotein synthetic peptides identify antigenic conformation.eighteen synthetic peptides have now been prepared from dengue (den) 2 virus, representing 80% of the extra-membranal domain of the den envelope (e)-glycoprotein. these peptides were selected based upon our previous results with murray valley encephalitis (mve) virus, computer analysis of the den virus sequence, and the predicted e-glycoprotein secondary structure. six of these peptides were "structural" peptides derived from either nonlinear amino acid sequences or predicted disulfide bridge-st ...19902371772
detection of dengue viral rna in mosquito vectors by mixed phase and solution hybridization.a mixed phase hybridization technique was developed to detect dengue virus type 2 (den-2) rna in pools of infected aedes albopictus mosquitoes using radiolabelled rna probes. this technique used a guanidine thiocyanate extraction procedure to simplify analyte preparation. the probes contained sequences complementary to portions of the ns-1 or ns-5 genes of the den-2 viral genome. one infected mosquito in a pool of 25 could be detected in approximately 48 h. rnas from den serotypes 1-4 were extra ...19902402251
arthropod-borne virus infections in western new guinea (irian jaya): a serological retrospection.a serological investigation, covering many localities throughout western new guinea (irian jaya) in 1958-1961 showed that: a general endemicity of arbovirus infections rather than sporadic epidemics, exists in the southern lowlands--large differences exist in geographical distribution of these viruses especially when comparing coastal areas of the southern, with those of the northern and north western parts of the island--in both arbovirus groups noticeable differences in altitude were observed ...1978749276
cultivation of dengue virus type 2 in baby hamster kidney cells in serum-free medium.propagation of dengue virus type 2 (new guinea c strain) was performed using a shaker culture of baby hamster kidney cells (bhk-21) cultivated in serum-free modified waymouth medium. maximum virus titer varied from 10(8.3) to 10(8.8) plaque forming units/ml after incubation of bhk-21 cells in suspension culture at 37 dgrees c for 40-48 hours post-infection.1979484777
protection of mice against japanese encephalitis virus by passive administration with monoclonal antibodies.we have identified and characterized nine antigenic epitopes on the e envelope of japanese encephalitis virus (jev) by using mab. passive administration of most of the anti-jev mab protected mice from i.v. challenge with 1.5 x 10(3) plaque-forming units of jev, jagar-01 strain. some mab, which possess high neutralization activity in vitro, showed high protection, and jev-specific n mab 503 was found the most protective. even an injection of 2.5 micrograms/mouse of mab 503 protected all mice from ...19882460542
serologically defined linear epitopes in the envelope protein of dengue 2 (jamaica strain 1409).antisera from dengue patients and dengue virus infected rabbits recognized octapeptides corresponding to linear amino acid sequences in the envelope protein of dengue 2 (jamaica 1409). although no peptide was recognized by sera from all dengue infected hosts, two peptides (216lplpwlpg223 and 448fsgvswtm455) were recognized by sera from all dengue 2 infected rabbits. one of these 448fsgvswtm455 was also recognized by sera from both the dengue 2 patients tested. no peptides were identified which r ...19892473720
absence of leukocytes permissive to dengue 2 virus in the acute phase of dengue hemorrhagic fever.patients with primary dengue infection developed dengue 2 virus (d2v) permissive peripheral blood leukocytes (pbl) 2--3 weeks after infection. pbl from healthy individuals with dengue antibody were permissive to d2v in vitro, suggesting that immunologically mediated in vitro d2v permissiveness persists for a relatively long time after recovery from dengue infection. however, pbl obtained from second infection dengue hemorrhagic fever patients did not support d2v growth during the acute phase of ...1979453450
cultivation of dengue virus type 2 in candidate substrates for vaccine production. 1978415061
stimulation of plasminogen activator inhibitor activity in human monocytes infected with dengue virus.human monocytes, in an essentially serum-free culture medium, were infected with dengue 2 virus in the presence of sub-neutralizing concentrations of antibody. changes in procoagulant activity (pca), in the plasminogen activator urokinase (uk), and the plasminogen activator inhibitor-2 (pai-2) were quantitated. one day after exposure to dengue virus, the cell-associated pai-2 activity in the infected monocytes was 562 +/- 9 mu/10(6) cells (mean +/- se) compared to 206 +/- 56 mu/10(6) cells for u ...19892492775
effect of dengue virus on procoagulant and fibrinolytic activities of monocytes.some of the fibrinolytic and coagulation enzymes that monocytes produce are urokinase, a plasminogen activator (pa); a pa-specific inhibitor (pai); and procoagulant activity (pca), which has been characterized as tissue factor. dengue infection in vivo is restricted to monocytes; however, it is unknown if dengue-infected monocytes undergo alterations in the production of pa, pai, and pca. this issue was addressed in studies in which monocytes were infected in vitro with dengue 2 virus in serum-f ...19892501855
virulence and immunogenicity of a temperature-sensitive dengue-2 virus in lower primates.clones of dengue-2 virus were tested for virulence by inoculation of rhesus monkeys and chimpanzees. although primates showed no overt signs of illness, inoculation with the parent virus or a subline of a large-plaque clone resulted in a viremia lasting 1 to 7 days. by these criteria, sublines of a small-plaque clone were significantly less virulent and produced little or no viremia in primate hosts. although they had a substantially reduced viremia, primates inoculated with the small-plaque sub ...1977409682
fluorescent antibody studies on the development of dengue-2 virus in aedes albopictus (diptera: culicidae). 1979396372
effect of passage history on dengue-2 virus replication in subpopulations of human leukocytes.three passage levels of dengue-2 virus strain pr-159, obtained during the course of deriving the attenuated s-1 vaccine, were tested for their ability to replicate in subpopulations of human peripheral blood leukocytes: (i) 6th primary african green monkey kidney (pgmk) cell passage (parent virus); (ii) 19th pgmk cell passage of a small-plaque-forming clone derived from the parent virus (s-1 pgmk virus); and (iii) virus derived by four additional passages of the s-1 pgmk virus in diploid fetal r ...1979121109
nucleotide sequence of the envelope protein gene of a malaysian dengue-2 virus isolated from a patient with dengue haemorrhagic fever. 19892587234
expression of the ns1 gene of dengue virus type 2 using vaccinia virus. dimerisation of the ns1 glycoprotein.a part of the genome of dengue virus type 2 spanning the coding region from the carboxy terminus of the envelope protein e to the beginning of the ns3 protein was expressed using recombinant vaccinia virus. additional constructs which contained open reading frames terminating within the ns1 or ns2a genes were also expressed. ns1 dimers were formed by extended ns1 molecules containing 61 amino acids of ns2a. no dimers were detected when ns1 was shortened by 79 amino acids at its carboxy terminus.19911826827
a serological study of japanese encephalitis virus infections in northern peninsular malaysia.this study describes the status of viral encephalitis in perak, malaysia during the year 1990. in addition, 14 cases selected from penang and perak during the years 1989 and 1990 are presented, with data showing titers of neutralizing antibodies against japanese encephalitis virus (jev) and dengue 2 virus, titers of antibodies against jev and dengue virus antigens as determined by deia, and a comparison of these with the presence of igm to jev and dengue virus. these data show that there probabl ...19911667957
processing of dengue virus type 2 structural proteins containing deletions in hydrophobic domains.the 5' end of the genome of the dengue virus type 2 encoding the structural proteins was expressed using recombinant vaccinia virus. three additional recombinants derived by deletion of selected dengue sequences within the parental construct were also expressed. they were designed to assess the role of hydrophobic domains in the processing of the viral polyprotein in intact cells. the first construct contained a deletion of nucleotides encoding most of the c protein; nucleotides encoding the hyd ...19921729986
[application of the polymerase chain reaction (pcr) to diagnosis in virology].recall of the principle of the pcr and of its advantages: rapidity, possible automatization, high sensitivity allowing the detection of minute amounts of infectious agents, specificity depending on that of the primers used for the detection of the amplified product. but this technic has to be used with care to avoid any contamination which might give false positive results and requires controls. this procedure would allow to analyze the evolution and the variability of infectious agents by their ...19911819420
the sensitivity of cell-associated dengue virus proteins to trypsin and the detection of trypsin-resistant fragments of the nonstructural glycoprotein ns1.extracts of vero cells infected with dengue virus type 2 were digested by trypsin in the presence and absence of detergents. the experiments were designed to test the models proposed for flavivirus translation in which the glycoproteins prm, e, and ns1 are inserted into the endoplasmic reticulum of the cell, whereas certain other nonstructural proteins are not. viral polypeptides were detected by the use of radiolabel, by immunoprecipitation, or by immunoblotting. the results obtained for ns3 an ...19911824904
analysis of inheritance of oral susceptibility of aedes aegypti (diptera: culicidae) to dengue-2 virus using isofemale lines.isofemale lines were compared to determine possible genetic variation in oral susceptibility within the fare strain of aedes aegypti (l.) to dengue-2 (den-2) virus. three groups of 12 isofemale lines each were tested statistically using the sas catmod procedure of analysis of variance. the "isofemale line" effect was highly significant, demonstrating genetic variability in oral susceptibility among females. the length of time eggs were stored before hatching influenced the oral susceptibility of ...19911941912
an improved method for the detection of peroxidase-conjugated antibodies on immunoblots.a sensitive method for the detection of antigen-antibody complexes on immunoblots is described which employs a modified substrate for peroxidase-conjugates. dengue virus proteins were chosen for study and were separated by sds-page followed by electrophoretic transfer onto sheets of nitrocellulose. virus-specific antigens bound to the nitrocellulose paper were then probed with both mouse monoclonal antibodies and human convalescent sera. antigen-antibody complexes were detected with anti-species ...19892668315
sequence analysis of cloned dengue virus type 2 genome (new guinea-c strain).sequences totalling 5472 nucleotides (nt) from four complementary dna (cdna) clones of the dengue virus type 2 (den-2) rna (new guinea strain, ngs-c) have been reported previously [yaegashi et al., gene 46 (1986) 257-267; putnak et al., virology 163 (1988) 93-103]. this report describes the complete nucleotide sequence, with the exception of about 7 nt at the 5'-noncoding region, of this rna genome derived from several cdna clones. it is 10,723 nt in length and contains a single long open readin ...19892714651
dengue-2 virus in kenya. 19901977046
processing, secretion, and immunoreactivity of carboxy terminally truncated dengue-2 virus envelope proteins expressed in insect cells by recombinant baculoviruses.two recombinant baculoviruses were constructed by inserting via the transfer vector pacym1 the genes coding for the structural proteins of dengue (den)-2 virus downstream from the polyhedrin promoter of autographa californica nuclear polyhedrosis virus. the two recombinants differed in truncation of 26 and 71 amino acids, respectively, in the carboxy-terminal sequence of den-specific envelope (e) glycoprotein. recombinant den-2 e glycoproteins were processed and transported to the surface of spo ...19911984665
nucleotide sequence of dengue 2 rna and comparison of the encoded proteins with those of other flaviviruses.we have determined the complete sequence of the rna of dengue 2 virus (s1 candidate vaccine strain derived from the pr-159 isolate) with the exception of about 15 nucleotides at the 5' end. the genome organization is the same as that deduced earlier for other flaviviruses and the amino acid sequences of the encoded dengue 2 proteins show striking homology to those of other flaviviruses. the overall amino acid sequence similarity between dengue 2 and yellow fever virus is 44.7%, whereas that betw ...19882827375
evidence that the mature form of the flavivirus nonstructural protein ns1 is a dimer.evidence is presented which indicates that the dengue-2 virus nonstructural protein ns1 (soluble complement fixing antigen) exists in infected bhk and mosquito cell cultures as part of a stable oligomer. identification of the dissociation products of the isolated oligomer and comparison of the number of n-linked glycans in native and denatured ns1 is consistent with the idea that the high-molecular-weight form of ns1 is a homodimer. by analyzing lysates of bhk cells infected with st. louis encep ...19882827377
outbreak of dengue fever in rural areas of parbhani district of maharashtra (india).outbreak of dengue fever in chikalthana, pimpalgaon and waloor villages in parbhani district of maharashtra (india) were investigated. clinically, the illness was typical of dengue fever except for the absence of maculopapular rash. a total of 42 acute, 14 late acute, 73 convalescent and 19 sera from contacts were collected. of the 15 virus isolates, 12 were identified as dengue virus type 2 and 1 as dengue virus type 1. serological tests confirmed the etiological role of dengue virus in the out ...19912022403
the first epidemic of dengue hemorrhagic fever in the people's republic of china.the first epidemic of dengue in china associated with significant severe and fatal hemorrhagic disease which met the world health organization case definition occurred on hainan island in 1985-1986. the epidemic began in zhan county in september 1985, spread throughout the coastal areas, and ultimately involved 13 counties and cities of the island in 1986. the mosquito vector was aedes aegypti. the morbidity associated with dengue infection on hainan island was 1,913 per 100,000 residents, with ...19912042704
[comparative study of dengue 2 virus replication and isoenzymes in two strains of aedes aegypti].this study, dealing with two strains of aedes aegypti from vietnam and french guiana, shows the variability of the genes coding for 11 isoenzymatic systems and the replication of the dengue 2 virus in parenterally infected mosquitoes. slight differences are observed in the characteristics of viral replication. no clear correlation is shown with enzymatic patterns which appear widely different from one strain to the other with four of the enzymes studied.19902085909
maturation process of japanese encephalitis virus in cultured mosquito cells in vitro and mouse brain cells in vivo.the maturation process of japanese encephalitis (je) virus in c6/36 cells in vitro and in mouse brain cells in vivo was studied by electron microscopy. in the c6/36 cell infection, 500 to 2250 virions per cell were released into the medium during the period of study; yet, no virus budding process was observed at the host cell membranes. je virions at various maturation stages appeared within the cisternae of rough endoplasmic reticulum (rer) of infected cells at 24 hours p.i.; and, although c6/3 ...19872889443
dengue-2 virus infection of human mononuclear cell lines and establishment of persistent infections.twenty three human mononuclear cell lines including ten myelomonocytic cell lines, eight b cell lines and five t cell lines, were examined to determine whether they could be infected with dengue-2 virus. all the cell lines were infected with dengue-2 virus as determined by immunofluorescent staining and by virus titration of culture supernatant fluids. k562, jiyoye and jurkat, respectively, showed the highest percentage of infected cells of these myelomonocytic, b and t cell lines. antibody to d ...19902178591
nucleotide sequence of the envelope glycoprotein gene of a dengue-2 virus isolated during an epidemic of benign dengue fever in tonga in 1974. 19902216784
functional and antigenic domains of the dengue-2 virus nonstructural glycoprotein ns-1.the gene coding for the nonstructural glycoprotein of dengue-2 virus was cloned, sequenced, and expressed in escherichia coli. there was about 70% conservation at the amino acid level with dengue serotypes 1 and 4 suggesting an important common function for this protein. conserved hydrophobic domains were found both before the amino-terminus and at the carboxy-terminus, consistent with transmembrane roles. evidence for at least partial translocation of ns-1 through the inner membrane of e. coli ...19882964755
variation among strains of aedes aegypti in susceptibility to oral infection with dengue virus type 2.we compared 18 aedes aegypti strains for oral susceptibility to dengue virus type 2 (den-2) using a feeding protocol in which all parameters remained constant, including the titer of the infectious bloodmeal. for most strains, no significant variation between replicates was observed. comparisons between pairs of strains showed variation of different degrees, and allowed us to characterize the strains with respect to their oral susceptibility to den-2.19902221225
expression of the structural proteins of dengue 2 virus and yellow fever virus by recombinant vaccinia viruses.vaccinia virus recombinants were constructed which contained cdna sequences encoding the structural region of dengue 2 virus (pr159/s1 strain) or yellow fever virus (17d strain). the flavivirus cdna sequences were expressed under the control of the vaccinia 7.5k early/late promotor. cultured cells infected with these recombinants expressed immunologically reactive flavivirus structural proteins, precursor prm and e. these proteins appeared to be cleaved and glycosylated properly since they comig ...19902260923
geographic classification of dengue-2 virus strains by antigen signature analysis.dengue-2 virus strains from different locations were compared by t1-rnase-resistant oligonucleotide fingerprinting and antigen signature analysis. the latter technique involved construction of radioimmunoassays using monoclonal antibodies that recognize nine distinct dengue-2 type-specific and flavivirus cross-reactive epitopes over a range of antigen concentrations. a statistical method was used to align unknown dengue antigen concentrations in different strain preparations, allowing comparison ...19862429440
topological mapping of unique epitopes on the dengue-2 virus ns1 protein using monoclonal antibodies.monoclonal antibodies were produced against two distinct thai dengue-2 (den-2) virus strains isolated in 1980 from dengue haemorrhagic fever patients. nine of 36 hybridomas produced monoclonal igg antibodies which reacted in radioimmune precipitation assays with the ns1 non-structural protein (42,000 mol. wt.) from den-2-infected c6/36 (aedes albopictus) cells. the virus specificity of ns1-reactive monoclonal antibodies was determined by indirect immunofluorescence assays using llc-mk2 cells inf ...19872434611
dengue virus-specific human t cell clones. serotype crossreactive proliferation, interferon gamma production, and cytotoxic activity.the severe complications of dengue virus infections, hemorrhagic manifestation and shock, are much more commonly observed during secondary infections caused by a different serotype of dengue virus than that which caused the primary infections. it has been speculated, therefore, that dengue hemorrhagic fever (dhf) and dengue shock syndrome (dss) are caused by serotype crossreactive immunopathological mechanisms. we analyzed clones of dengue serotype crossreactive t lymphocytes derived from the pb ...19892475573
partial nucleotide sequence and deduced amino acid sequence of the structural proteins of dengue virus type 2, new guinea c and puo-218 strains.the nucleotide sequence and the deduced amino acid sequence for the genes encoding the structural proteins of two strains of dengue virus type 2 (den-2) were determined from cdna clones. the genes for c, prm(m) and e proteins were sequenced for the prototype den-2 virus, the new guinea c strain. also sequenced were the prm(m) and e genes of puo-218. this strain of den-2 was isolated during 1980 in bangkok and had received a limited number of laboratory passages. comparisons of the newly determin ...19883385407
[antigen signature analysis of dengue-2 viruses strains in hainan china].in this paper, we try to define the extent of antigenic variation between dengue-2 viruses from hainan province, which had been isolated over a period of 3 years (1985-1987). the dengue-2 viruses were compared with the prototype new guinea b strain and were subjected to antigen signature analysis. eight strains of dengue-2 virus were analyzed by three monoclonal antibodies: flavivirus group, subcomplex dengue-2 type-specific reactive epitopes, over a range of antigen concentration. five out of e ...19892479176
newly synthesized dengue-2 virus nonstructural protein ns1 is a soluble protein but becomes partially hydrophobic and membrane-associated after dimerization.in a previous paper (g. winkler, v. b. randolph, g. r. cleaves, t. e. ryan, and v. stollar, 1988, virology 162, 187-196) we showed that the newly synthesized dengue-2 virus nonstructural protein, ns1, exists briefly as a monomer and then undergoes dimerization. we demonstrate here that the dimerization of ns1 is associated with a change in hydrophobicity and sedimentability of this protein. newly synthesized monomeric ns1 is a hydrophilic and water-soluble protein which cannot be pelleted at 75, ...19892525840
nucleotide sequence of the envelope protein gene of a malaysian dengue-2 virus isolated from a patient with dengue shock syndrome. 19892587243
profiles of antibody-dependent enhancement of dengue virus type 2 infection.antibody-dependent infection enhancement (ade) was studied with p-388d1 mouse macrophage-like cells, 21 dengue virus type 2 (den-2) strains, and 8 monoclonal antibodies reactive with flavivirus group-specific or dengue serotype-specific determinants. testing a constant number of virions against serial dilutions of antibody for their ability to infect p-388d1 cells, a reproducible 'enhancement profile' was observed. the profile was characterized by (1) appearance, peak, decline, and disappearance ...19873504546
dengue virus premembrane and membrane proteins elicit a protective immune response.we have constructed recombinant vaccinia viruses that express the premembrane (pre-m), membrane (m), or the cleaved, residual portion of pre-m (non-m) proteins of dengue 4 virus, or the pre-m, non-m, or envelope (e) proteins of dengue 2 virus, to evaluate their ability to induce protective immunity in mice. cells infected with these recombinants make proteins of expected size. mice immunized with recombinants expressing dengue 4 pre-m or m were protected against subsequent dengue 4 encephalitis ...19911926792
genetic variation and microevolution of dengue 2 virus in southeast asia.dengue 2 (den 2) virus strains collected from dengue hemorrhagic fever (dhf) patients and aedes aegypti mosquitoes in thailand, burma, and vietnam over a 25-year period have been analyzed by computer assisted t1-rnase-resistant oligonucleotide fingerprinting. fifty-seven den 2 virus strains of the thailand topotype were separated into four major clusters by phylogenetic analysis of 97 unique oligonucleotides identified in a common well-resolved region of the fingerprints. similarities in the 57 ...19892529700
[transmission cycles of arboviruses in madagascar].some arboviruses are highly pathogenic for men or animals. arboviruses epidemiological patterns in madagascar were determined by entomological, serological, and virological surveys. we listed potentials arboviruses vectors in madagascar. entomological results generated by us during five years, as well as prior to, are shown. we caught more than 150,000 hematophagous arthropods, belonging to 107 species at least. 3 of these species were new. 4183 inoculation pools were done. we studied serollogic ...19892576622
nucleotide sequence of the envelope protein gene of a malaysian dengue-2 virus isolated from a patient with dengue fever. 19892587242
alterations in thrombopoiesis in patients with thrombocytopenia produced by dengue hemorrhagic fever.the causes of thrombocytopenia, one of the most dangerous symptoms in the course of dengue hemorrhagic fever (dhf), are not yet clear. we studied patients with dhf (dengue virus type 2), grouped according to days of illness, platelet counts, serum thrombopoietin (tpo) levels, and bone marrow differential counts. during the thrombocytopenic phase of disease (3rd-8th days) the tpo levels were not increased in spite of low platelet counts. beginning from the 6th-7th day in some patients, a rapid in ...19863808936
[arbovirus transmission cycles in madagascar].some arboviruses are highly pathogenic for men or animals, arboviruses epidemiological patterns in madagascar were determined by entomological, serological, and virological surveys. we listed potentials arboviruses vectors in madagascar. entomological results generated by us during five years, as well as prior to, are shown. we caught more than 150,000 hematophagous arthropods, belonging to 107 species at least. 3 of these species were new. 4183 inoculation pools were done. we studied serologica ...19892751393
rapid chemical mapping of dengue virus variability using rna isolated directly from cells.osmium tetroxide and hydroxylamine (in combination with piperidine) have previously been shown to cleave mismatched t and c bases, respectively, in dna.dna heteroduplexes. in this work we report that mismatched t and c bases were similarly cleaved in dna.rna heteroduplexes of nucleic acids derived from different strains of dengue virus type 2. further, some matched t or c bases one or two bases from mismatches were also chemically reactive and thus cleavable as detected by minor bands. cleavages ...19892592522
the reemergence of dengue in china.in 1978, dengue was reported in china for the first time in 32 years. since then, epidemics involving hundreds of thousands of people have occurred in guangdong and guangxi provinces and on hainan island. these epidemics were caused by all four types of dengue virus. aedes aegypti was the vector in coastal areas, while aedes albopictus was the vector in inland regions. during these epidemics, case rates were very high (greater than 50%) in some areas. case-fatality rates were generally less than ...19892665017
monoclonal antibodies against dengue 2 virus e-glycoprotein protect mice against lethal dengue infection.a panel of 11 murine monoclonal antibodies directed against dengue type 2 was evaluated for antigen specificity by dot immunobinding assay and western blot analysis and for in vitro and in vivo biological activities. nine of the 11 monoclonal antibodies reacted with viral e-glycoprotein based on the western blot analysis; one reacted with a 36 kd protein present in dengue-infected c6/36 mosquito cells. the nine e-glycoprotein-reactive monoclonal antibodies also neutralized dengue 2 virus in a pl ...19873826503
processing of nonstructural proteins ns4a and ns4b of dengue 2 virus in vitro and in vivo.the production, from polyprotein precursors, of two hydrophobic nonstructural proteins of dengue 2 (den2) virus, ns4a and ns4b, was analyzed both in cell-free systems and in infected cells. in den2-infected cells, ns4b is first produced as a peptide of apparent size 30 kda; ns4b is then post-translationally modified, in an unknown way, to produce a polypeptide of apparent size 28 kda. the rate and extent of ns4b modification was found to be cell-dependent; in bhk cells the half-time for the conv ...19911683727
serological evidence of dengue fever among refugees, hargeysa, somalia.epidemics of a malaria-like illness affected several thousand residents of the dam camp, a refugee camp near hargeysa in somalia, during 1985, 1986, and 1987. the disease was characterized by fever, chills, sweats, headache, back and joint pains for as long as 10 days in some patients. blood smears from acutely ill patients were negative for malaria. of 28 acute and 10 convalescent sera tested by the indirect fluorescent antibody (ifa) and by the hemagglutination inhibition (hi) tests, all were ...19892600591
lethal 17d yellow fever encephalitis in mice. i. passive protection by monoclonal antibodies to the envelope proteins of 17d yellow fever and dengue 2 viruses.monoclonal antibodies to the envelope proteins (e) of the 17d vaccine strain of yellow fever virus (17d yf) and to dengue 2 virus were examined for their ability to confer passive protection against lethal 17d yf encephalitis in mice. all 13 igg anti-17d yf antibodies, regardless of neutralizing capacity, conferred solid protection when given in a relatively high dose prior to intracerebral inoculation of virus. three antibodies with high in vitro neutralizing titres were all protective at a low ...19863944585
effect of adjuvant vaccines on dengue virus type 2 immune ascitic fluid production.in a comparison of dengue type 2 immune mouse ascitic fluid immunization schedules, a schedule in which adjuvant vaccines were not used produced neutralizing antibody titers that were specific and a mouse mortality rate that was lower, resulting in a greater yield of ascitic fluids. in the schedules in which emulsified adjuvant vaccines were used, the quality of the emulsion had little effect on antibody titer produced.19853980697
antibody-dependent enhancement of dengue 2 virus in people of white descent in cuba. 19872883360
detection of some dengue-2 virus antigens in infected cells using immuno-microscopy.immunoelectron microscopy was used to detect the distribution of some dengue-2 virus proteins in infected vero and aedes albopictus (c6/36) cells. it was found that the envelope protein (gp 60) was located in clumps on the surface of plasma membrane, and accumulated very little in the infected cytoplasm. however no envelopment of dengue-2 virus nucleocapsids through the plasma membranes was observed. in contrast, the ns 3 (p 67) protein was distributed throughout the whole cytoplasm. no specific ...19892650656
host-induced modification of dengue-2 virus surface antigens in aedes albopictus cells. 19734132537
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