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antibody-dependent enhancement of tick-borne encephalitis virus infectivity.fourteen mouse monoclonal antibodies raised against tick-borne encephalitis virus (tbev) and polyclonal antisera raised against six other flaviviruses, edge hill (ehv), japanese encephalitis (jev), langat (lgtv), louping ill (liv), west nile (wnv) and yellow fever (yfv), were tested for their ability to enhance the replication of tbev in cells of the mouse macrophage-like line p388 d1, and for their reactivity in elisa and haemagglutination inhibition (hi) tests. irrespective of their specificit ...19852991448
viral infections of little blue penguins (eudyptula minor) along the southern coast of australia.serum antibodies to strains of avian paramyxovirus and flavivirus were detected in little blue penguins sampled at port campbell and phillip island, victoria, australia. no antibody to newcastle disease virus (ndv) was detected in 267 sera collected, although one penguin captured for experimental studies had a hemagglutination-inhibition antibody titer of 2(4) to this virus. experimental studies showed that the avian paramyxovirus designated apmv-im and strain v4 of ndv were non-pathogenic for p ...19852993680
conditions for haemolysis by flaviviruses and characterization of the haemolysin.the 17d vaccine strain of yellow fever virus (yf 17d) was used to establish the optimal conditions for lysis of chick erythrocytes. tissue culture-grown, polyethylene glycol-concentrated virus showed peak activity at ph 5.4 in citrate buffer when incubated at 37 degrees c. a further two- to fourfold increase in titre was obtained by pretreatment of the chick erythrocytes with 250 micrograms/ml trypsin. these conditions were also shown to be optimal for japanese encephalitis (je), west nile (wn) ...19852995565
human antibody response to immunization with 17d yellow fever and inactivated tbe vaccine.the antibody response against flaviviruses tick-borne encephalitis (tbe), kyasanur forest disease (kfd), murray valley encephalitis (mve), west nile fever (wnf), japanese b encephalitis (je), dengue 2 (den-2), and yellow fever (yf) was studied in humans after administration of an inactivated tbe virus vaccine. individuals were either prevaccinated with 17d yellow fever (experimental group) or without any previous exposure to flaviviruses (control group). the appearance of serum titres of homolog ...19852995571
premortem isolation of saint louis encephalitis virus: case report and implications for hospital and laboratory personnel. 19852995935
amino-terminal amino acid sequences of structural proteins of three flaviviruses.n-terminal amino acid sequences of structural proteins of three flaviviruses, yellow fever, st. louis encephalitis, and dengue-2 viruses, have been obtained. the glycoproteins of these three viruses are 52-60% conserved in the region sequenced, depending upon which pair of viruses are compared, and 40% of the amino acids are invariant in all three viruses. thus, flaviviruses are closely related and have in all probability descended from a common ancestor. furthermore, residues important in the s ...19852998002
powassan viral encephalitis: a review and experimental studies in the horse and rabbit.powassan virus strain m794, a member of the flavivirus genus known to infect man and animals in canada, was inoculated intracerebrally into rabbits and horses. no clinical signs were observed in rabbits, but widespread encephalitis resulted, characterized by lymphoid perivascular cuffing, lymphocytic meningitis, and lymphocytic choroiditis. in horses, eight days after inoculation, prominent neurological signs occurred and lesions were those of non-suppurative encephalomyelitis, neuronal necrosis ...19852996203
neutralization of yellow fever virus studied using monoclonal and polyclonal antibodies.monoclonal and polyclonal antibodies with known specificity for either the 54k envelope glycoprotein or the 48k non-structural glycoprotein of yellow fever (yf) virus-infected cells were studied in plaque reduction neutralization tests. viruses employed in the tests comprised wild-type and vaccine strains of yf and a selection of other flaviviruses. of 17 monoclonal antibodies examined, six of the 54k-specific antibodies neutralized at least one yf preparation. both vaccine and wild-type yf viru ...19852999305
togaviridae.the family togaviridae comprises four genera: alphavirus (with 26 species), rubivirus (one species), pestivirus (three species), and arterivirus (one species). the main characteristics of the member viruses are: (i) the virus particles are spherical, 50-70 nm in diameter, including an envelope with surface projections that incorporate two or three polypeptides, usually glycosylated; (ii) the nucleocapsid comprises a core protein and a single strand of positive-sense rna, molecular weight about 4 ...19852999027
flaviviridae.the family flaviviridae comprises the genus flavivirus, which contains 65 related species and two possible members. they are small, enveloped rna viruses (diameter 45 nm) with peplomers comprising a single glycoprotein e. other structural proteins are designated c (core) and m (membrane-like). the single strand of rna is infectious and has a molecular weight of about 4 x 10(6) and an m7g 'cap' at the 5' end but no poly(a) tract at the 3' end; it functions as the sole messenger. the gene sequence ...19853000978
[persistence of the tick-borne encephalitis and langat viruses in mouse thymocytes in experimental infection against a background of cyclophosphane-induced immunodepression].the intensity of infection of immunocompetent organ cells with tick-borne encephalitis and langat viruses in mice with temporary immunodeficiency induced by cyclophosphane is characterized. using the method of infectious centres it was shown that at various stages of the infectious process splenocytes, bone marrow cells and thymocytes may be target cells for both viruses tested. the viruses persist for over 6 weeks in brain and thymocytes of clinically normal mice if at the time of inoculation t ...19853000083
site of suppression of banzi viral replication by an antiviral factor released from aedes albopictus cells persistently infected with banzi virus.the ability of the antiviral factor present in culture medium of aedes albopictus cells persistently infected with the flavivirus, banzi virus, to inhibit the replication of banzi virus was examined. the anti-banzi viral factor did not inhibit the uncoating of the virion. levels of viral rna were markedly reduced in mosquito cells treated with the antiviral factor. syntheses of negative-strand and of positive-strand viral rna species were inhibited to approximately the same extent. this inhibiti ...19853002069
stimulation of helper/delayed-type hypersensitivity t cells by flavivirus infection: determination by macrophage procoagulant assay.west nile virus (wnv)-immune spleen cells produced an inducer of macrophage procoagulant activity (mpca) on restimulation with wnv in vitro. this response was specific for wnv and depended on the presence of thy 1+, l3t4+ and also ia+ cells but not lyt 2+ cells. it could be induced by culture with large amounts of non-infectious, u.v.-irradiated virus or with high doses of infectious virus. inoculation of mice with low titres of infectious, but not with u.v.-irradiated, virus primed for this in ...19863003235
classification of barmah forest virus as an alphavirus using cytotoxic t cell assays.barmah forest virus, an arbovirus, does not cross-react convincingly with alpha-, flavi- or bunyavirus immune sera. secondary cytotoxic t cells generated in vitro immune to a number of alphaviruses cross-lyse barmah forest virus-infected target cells. flavivirus (west nile and kunjin)- and bunyamwera virus-immune tc cells lyse homologous virus-infected target cells, but not alphavirus-infected targets. using cytotoxic t cell assays barmah forest virus can be classified as an alphavirus.19863003237
genetic aspects of macrophage involvement in natural resistance to virus infections.macrophages are thought to constitute an important element in the body's natural defense against invasion and dissemination of viruses. possible antiviral mechanisms of macrophages are defined and referred to as intrinsic, i.e. the ability of macrophages to serve as a nonpermissive barrier between the virus and susceptible cells and extrinsic, i.e. the ability of macrophages to affect the virus or virus replication in surrounding cells. most studies on the role of macrophages in natural resistan ...19853002974
antibody enhanced viral growth in macrophages.antiviral antibody can promote viral entry into macrophages by pathways involving cellular receptors for the fc portion of immunoglobulin or for complement components. whether virus taken up through these routes is restricted or results in productive infection depends upon a balance between a number of variables. these include the virus strain and dose, the macrophage source and state of activation, the concentration, class and viral specificity of the antibody, and environmental factors such as ...19853002973
partial nucleotide sequence of the murray valley encephalitis virus genome. comparison of the encoded polypeptides with yellow fever virus structural and non-structural proteins.the sequence of 5400 bases corresponding to the 5'-terminal half of the murray valley encephalitis virus genome has been determined. the genome contains a 5' non-coding region of about 97 nucleotides, followed by a single continuous open reading frame that encodes the structural proteins followed by the non-structural proteins. amino acid sequence homology between the murray valley encephalitis and yellow fever (rice et al., 1985) polyproteins is 42% over the region sequenced. the start points o ...19863009829
experimental infection with murray valley encephalitis virus: galahs, sulphur-crested cockatoos, corellas, black ducks and wild mice.orally infected culex annulirostris or intravenous injections were used to infect 10 galahs, 15 sulphur-crested cockatoos, 12 corellas, 4 black ducks and 10 wild mice with murray valley encephalitis (mve) virus. the birds produced moderate viraemias of titres of log 10(2.0)-10(6.0) suckling mouse intracerebral (smic) ld50/ml for durations of 1-9 d. however, the wild mice developed low grade viraemia for 1-4 d. recipient cx annulirostris feeding on viraemic birds sustained infection rates of 0-10 ...19853004402
arbovirus infections of humans in new south wales. seroepidemiology of the flavivirus group of togaviruses.a seroepidemiological study of 16 842 human sera, collected in 1981 and 1982 from all health regions of new south wales, was carried out using the haemagglutination-inhibition (hi) test and eight australasian flaviviruses: murray valley encephalitis (mve); kunjin (kun); alfuy (alf); stratford (str); kokobera (kok); edge hill (eh); sepik (sep); and saumarez reef (sre). a limited survey was also carried out with two recently discovered flaviviruses, gadgets gully and csiro 946. antibody prevalence ...19853007952
partial n-terminal amino acid sequences of three nonstructural proteins of two flaviviruses.partial n-terminal amino acid sequences for the three largest nonstructural proteins of two flaviviruses, yellow fever virus and st. louis encephalitis virus, have been obtained. the determined sequences of these proteins exhibit significant amino acid sequence homology, and allow the positioning of these three nonstructural proteins in the polyprotein sequence deduced from the nucleotide sequence of yellow fever virus (c. m. rice, e. m. lenches, s. r. eddy, s. j. shin, r. l. sheets, and j. h. s ...19863008425
inhibition of banzi viral rna synthesis in bhk-21 cells by banzi virion matrix protein.treatment of bhk-21 cells with purified matrix (m) protein isolated from banzi virions resulted in decreased production of banzi virus and in reduced levels of virus-specific positive-strand and negative-strand rna. the m protein had no effect on the uncoating of the viral genome. this inhibition was virus-specific since the replication of unrelated togaviruses in bhk-21 cells was not affected. purified m protein inhibited the in vitro activity of the banzi viral rna polymerase; prior treatment ...19863009352
arbovirus infection in a murray valley community.serum antibodies to ross river virus and murray valley encephalitis virus were measured during 1974-1975 in residents of echuca, an urban murray valley community. a representative group of volunteers was obtained by random selection of households. the prevalence of antibodies to both viruses increased progressively with age. prevalence was equal in both sexes for both viruses in all age groups, indicating that the risk of infection was mainly determined by geography rather than by personal activ ...19863010928
analysis of structural properties which possibly are characteristic for the 3'-terminal sequence of the genome rna of flaviviruses.recently we have shown that an open reading frame comprising 10290 nucleotides is present on the infectious, single-stranded genome rna of the west nile flavivirus. we have now isolated cloned cdna representing the 3'-terminal untranslated region of this molecule. the sequence of this region which comprises 571 nucleotides is given in this report. recently, the nucleotide sequence of the genome rna of the yellow fever flavivirus has been described. a comparative analysis of the 3'-terminal untra ...19863011975
genetically controlled resistance to flaviviruses within the house mouse complex of species. 19863015496
arbovirus infections in several ontario mammals, 1975-1980.serological studies for arboviruses were conducted on 725 animal sera collected in 22 ontario townships between 1975 and 1980 including 44 coyote (canis latrans), 277 red fox (vulpes vulpes), 192 raccoon (procyon lotor) and 212 striped skunk (mephitis mephitis). hemagglutination inhibition antibodies to two flaviviruses, namely st. louis encephalitis and powassan were found in 50% of coyote, 47% of skunk, 26% of fox and 10% of raccoon sera. similarly, hemagglutination inhibition antibodies to a ...19863017527
genetically controlled resistance to virus infections of the central nervous system. 19853014607
antigenic analysis of yellow fever virus glycoproteins: use of monoclonal antibodies in enzyme-linked immunosorbent assays.a sensitive enzyme-linked immunosorbent assay with biotin and streptavidin (b/sa elisa) was developed for the specific detection of yellow fever (yf) viruses. monoclonal antibodies (mca) specific for the envelope (e) glycoprotein or the non-structural glycoprotein (nv3) of yf virus-infected cell lysates were tested by antigen and antibody capture b/sa elisa against yf viruses and a large number of other flaviviruses. in an antigen capture assay, with suckling mouse brain antigens, mca directed a ...19863016014
illness caused by a kokobera-like virus in south-eastern australia.three patients who lived in south-eastern australia and who suffered acute polyarticular illnesses in the summer months of 1983-1984 and 1984-1985 are described. two patients lived in the southwestern plains of new south wales and one in bairnsdale in eastern victoria. serological studies implicated kokobera virus, a flavivirus, as the likely causative agent. this would appear to be the first report to indicate the pathogenicity of kokobera virus.19863016489
the 3'-nucleotides of flavivirus genomic rna form a conserved secondary structure.the terminal noncoding regions of viral rna genomes are presumed to contain signal sequences and sometimes also secondary structures involved in regulating viral rna synthesis. such signals would be expected to be highly conserved among related viruses. in order to identify replication signal features for flaviviruses we have compared the 3'-terminal nucleotide sequences of west nile virus (wnv), saint louis encephalitis (sle) virus, and yellow fever virus (yfv) genome rnas. the existence of a s ...19863016981
genetic analysis of kunjin virus isolates using haeiii and taqi restriction digests of single-stranded cdna to virion rna.the genotypic relatedness of 15 kunjin (kun) virus isolates from widely separated geographic regions in australia was examined at the molecular level. haeiii and taqi restriction digest profiles of cdna transcribed from virion rna revealed a close genetic similarity between all isolates. we estimate that the nucleotide sequence divergence between any pair of kun isolates is probably less than 1%. we conclude that a single kun genetic type has existed in enzootic and epizootic areas of virus acti ...19863017278
[results of studying foci of arbovirus infections in the southern maritime territory]. 19863018466
[detection of the koutango virus (flavivirus, togaviridae) in somalia]. 19863018465
mosquito-borne virus diseases of man in southern africa. 19863022406
cloning full-length dengue type 4 viral dna sequences: analysis of genes coding for structural proteins.dna sequences (approximately 11,000 nucleotides) representing the full-length genome of the dengue virus type 4 were cloned. the sequence of the first 2,429 nucleotides at the 5' terminus which includes the coding region for the structural proteins is presented. the virion structural proteins are encoded in one long open reading frame specifying a polyprotein precursor which is apparently proteolytically cleaved by a mechanism resembling that proposed for expression of structural proteins of oth ...19863022479
relevance of detection of immunoglobulin m antibody response in birds used for arbovirus surveillance.young chickens were inoculated with 5,000 pfu of eastern equine encephalitis (eee) virus and bled at intervals thereafter for determinations of hemagglutination-inhibiting (hi), neutralizing (n), immunoglobulin m (igm), and igg antibodies. hi, n, and igm antibodies were first detected 4 days after infection, and igg was detected 7 days after infection. all four antibodies persisted through day 90 after infection. hi, n, and igm antibody titers remained elevated and were not cross-reactive with t ...19863021813
[meningoencephalitis caused by the st. louis encephalitis virus]. 19853022104
post-encephalitic epilepsy and arbovirus infections in an isolated rainforest area of central liberia.among a population of 4.436 bassa, kpelle and mano people in the gbawein and wroughbarh clan region of grand bassa country, liberia, 123 cases of epilepsy could be documented. in 38% of these cases infections involving the central nervous system precipitated the onset of seizures. sera from 67 epilepsy patients, 50 direct healthy relatives and 22 geographically matched controls were tested for antibodies to 16 arboviruses of the togaviridae and bunyaviridae known to occur in africa. antibodies t ...19863018970
[nucleotide sequence of the genome region of the tick-borne encephalitis virus coding for structural virion proteins].rna of a flavivirus-tick-borne encephalitis virus (strain sofjin) was subjected to reverse transcription and the dna copy was transformed into double-stranded dna by action of e. coli dna-polymerase i (klenow's fragment). this dna was annealed with pbr322 plasmid. the recombinant plasmids were cloned in e. coli k802. the nucleotide sequence of the inserts of the clones coding for region of structural proteins c, pre-m, e and nonstructural protein ns1 was determined by the maxam-gilbert method. t ...19863022757
characterization of west nile virus rna-dependent rna polymerase and cellular terminal adenylyl and uridylyl transferases in cell-free extracts.to facilitate further studies of flavivirus transcription, cell extraction methods and in vitro reaction conditions which increased west nile virus (wnv) rna-dependent rna polymerase activity were determined. subcellular fractions from wnv-infected bhk-21/w12 cells were characterized with regard to their protein and rna content and in vitro polymerase activity. in both a cytoplasmic fraction, designated s1, and a fraction enriched for outer nuclear membranes, designated s2, seven virus-specific ...19863023663
flaviviruses in south africa: diagnostic procedures.employing rabbit immune serum, 10 flaviviruses known to be present in south africa could be divided into 5 serological subgroups. the subgroups conform to the general pattern described for the group. sera from experimentally infected calves and lambs were monospecific in neutralization tests, but cross-reacted in haemagglutination inhibition tests. these results suggest that sheep and cattle sera from the field can best be tested by microneutralization tests. the greater sensitivity of embryonat ...19863025791
neutralizing antibody response to japanese encephalitis inactivated mouse brain vaccine among laboratory personnel.among vaccinees given two doses of je nakayama strain liquid vaccine, 41.8% had significant neutralizing (n) antibody response to the p20778 strain and 48.6% to the japanese nakayama strain. among vaccinees who received three doses of the freeze-dried vaccine, the proportion of positive reactors was 53.8% when the sera were tested with the p20778 strain and 47.4% with the nakayama strain. a fairly large proportion of those vaccinees who had responded positively to the latter vaccine were found t ...19863024366
nucleotide sequence and deduced amino acid sequence of the structural proteins of dengue type 2 virus, jamaica genotype.the nucleotide sequence of the 5'-terminal 2469 bases of dengue 2 (jamaica genotype) virus has been determined and the encoded proteins compared with those of yellow fever and west nile viruses, which belong to different flavivirus serogroups. the cdna clone which was sequenced contains a 5'-noncoding region of 96 nucleotides followed by a single open reading frame coding for the structural proteins 5'-c-prm(m)-e-3' and the beginning of the ns1 nonstructural protein. the amino acid sequence homo ...19863024394
flaviviruses in south africa: pathogenicity for sheep.sheep are susceptible to at least 5 of the 10 flaviviruses known to be present in south africa. sheep, 7-9 months of age, injected with wesselsbron, west nile, banzi, uganda-s and ar 5189 (an unidentified virus related to banzi and uganda-s), responded with a moderate febrile reaction, a low grade viraemia of short duration and the production of virus neutralizing antibodies. the most pronounced manifestations of infection were encountered in pregnant ewes. infection with west nile, banzi and ar ...19863025792
[experimental infection of ixodid ticks with karshi virus].the ixodid ticks hyalomma asiaticum, h. anatolicum, dermacentor niveus were infected experimentally with karsha virus. the virus replication has been proved to occur in the tick's organism. the titre of the virus grows gradually in infected ticks. entering the tick's gut during its feeding virus particles penetrate into the gut walls where primary multiplication and accumulation of the virus take place.19863024093
single-radial-haemolysis test for diagnosing flavivirus infections, particularly japanese encephalitis.use of the single-radial-haemolysis (srh) technique for the diagnosis of flavivirus infections is described. a large number of paired and single convalescent serum samples collected from cases of encephalitis during two major outbreaks in kolar district of karnataka state in india during 1977 and 1979 were tested by this technique. the results were compared with those obtained in the haemagglutination inhibition (hi) test in all cases, and the complement fixation (cf) and neutralization tests in ...19863026673
an enzyme-linked immunosorbent assay for detection of flavivirus antibodies in chicken sera.an enzyme-linked immunosorbent assay (elisa) was developed to determine the presence of flavivirus antibodies to murray valley encephalitis (mve) and kunjin viruses in sentinel chicken sera. the development of a quick, reliable assay to detect antibodies to mve was an essential part of a large-scale surveillance programme to monitor arbovirus activity in western australia. this assay was developed for use with alkaline phosphatase conjugated goat anti-mouse igg using mouse anti-chicken globulin ...19873027114
ultrastructural studies of kunjin virus-infected aedes albopictus cells.ultrastructural changes in aedes albopictus cells infected with kunjin virus were characterized from 12 to 72 h post-infection. early in infection (16h), there were no prominent ultrastructural changes except for an increase in the number of vacuoles in the cytoplasm. as the infection progressed the rough endoplasmic reticulum appeared to lengthen and whorls of fibres were observed within some vacuoles. virus particles were observed in small numbers scattered in the cytoplasm between 24 to 30 h ...19873029292
detection of st. louis encephalitis virus antigen in mosquitoes by capture enzyme immunoassay.surveillance methods that measure st. louis encephalitis (sle) virus activity in nature may provide forewarning of its epidemic occurrence in humans. an antigen capture enzyme immunoassay was developed to detect sle virus in infected mosquitoes. the assay detected purified sle viral antigen at a concentration of 62 pg/0.1 ml when antigen was incubated overnight; 250 pg/0.1 ml was detected in a single-day assay (antigen incubated for 3 h). the assay detected 67.9 and 70.8% of laboratory-prepared ...19873029170
characterization of novel viral polyproteins detected in cells infected by the flavivirus kunjin and radiolabelled in the presence of the leucine analogue hydroxyleucine.vero cells were infected by kunjin virus and radiolabelled in the presence of the leucine analogue, threo-beta-hydroxy-dl-leucine (thl). this analogue is known to prevent preprotein processing in cell-free systems when incorporated into signal peptides. novel kunjin virus-specified proteins were detected, namely gp140, p120 and gp92; the designations for the proteins indicate their approximate mr x 10(-3) and whether they are glycosylated. the glycoproteins gp140 and gp92 were observed in cells ...19873029280
partial nucleotide sequence of st. louis encephalitis virus rna: structural proteins, ns1, ns2a, and ns2b.cdna clones of the st. louis encephalitis (sle) virus genome have been obtained and the nucleotide sequence of 4.7 kb corresponding to the 5' terminal half of the genome determined. the genome contains a 5' noncoding region of 98 nucleotides followed by a single continuous open reading frame that encodes three structural proteins in the order capsid (c), membrane precursor (prm)-membrane (m), and envelope (e). immediately following the c-terminus of e are located nonstructural proteins ns1 throu ...19873027980
cross-infection enhancement among african flaviviruses by immune mouse ascitic fluids.cross-infection enhancement of seven african flaviviruses by subneutralising concentrations of antibody in immune ascitic fluids was investigated in p388d1 cell culture. infection by all the seven flaviviruses tested was enhanced by homologous and at least one of six heterologous immune mouse ascitic fluids (imaf) tested. enhancement ratios and enhancing antibody titres were higher in homologous than in heterologous enhancement. zika, wesselsbron, uganda s and west nile viruses were enhanced in ...19873028713
characterization of kunjin virus rna-dependent rna polymerase: reinitiation of synthesis in vitro.rna-dependent rna polymerase (rdrp) activity was characterized in a cytoplasmic extract of kunjin virus-infected vero cells at 24 hr. the activity was influenced, possibly indirectly, by the length of prior treatment of infected cells with actinomycin d; however, 6 micrograms/ml actinomycin d and 10(-5) m alpha-amanitin in the rdrp assay had no effect. the replication complex was membrane-bound and mg2+ was essential for rdrp activity. incorporation was more dependent on exogenous utp and gtp th ...19873029975
[study of immunological mechanisms of action of temperature and emotional stress factors in experimental flavivirus infections].the influence of two stress factors, sharp changes in temperature and hypokinesia, on the course of experimental tick-borne encephalitis and langat virus infections in mice has been studied. the data obtained in this study indicate that both factors produce defects in t- and b-cell-mediated immunity, accompanied by the activation of asymptomatic infection and the decrease of the mean survival time in acute infection. these two stress factors, differing in their intensity and nature (physical and ...19863030031
antibody-mediated enhancement of wesselsbron virus in p388d1 cells.antibody-mediated enhancement of wesselsbron virus was investigated in p388d1 cell cultures. virus infection was enhanced in culture by various dilutions of homologous and heterologous flavivirus antibody. highest enhancement ratios and enhancing antibody titres were obtained with the homologous antibody. enhancement of wesselsbron virus infection in p388d1 cultures was also dependent on the multiplicity of infection (moi) used; cultures infected at the lowest moi produced the highest enhancemen ...19863031959
the neurovirulence of flaviviruses in crab-eating monkeys (macaca fascicularis).the neurovirulent properties of attenuated dengue-2 and yellow fever (yf) vaccines, dengue-2 (den-2) and japanese encephalitis (je) viruses were studied in crab-eating monkeys (macaca fascicularis). number of central nervous system sites (as proportion affected) with neurovirulence (nv) lesions were compared. the results indicate that these monkeys reliably developed nv-lesion when inoculated with either je or yf vaccine viruses (87%). nv-lesions occurred in a minority when inoculated with den-2 ...19863033834
sequence of 3000 nucleotides at the 5' end of japanese encephalitis virus rna.the 5' region of the japanese encephalitis virus (jev) rna was cloned and 3000 nucleotides (nt) were determined by sequencing dna complementary to viral rna, and genomic rna, using oligodeoxynucleotide primers and the dideoxy chain-termination reaction. comparison of the nt sequence and the reduced amino-acid sequence of jev with those of other flaviviruses showed significant homologies, which allowed locations to be assigned for three structural proteins.19863030895
detection of flavivirus rna in infected cells using photobiotin-labelled hybridization probes.ten plasmids containing viral cdna inserts of portions of the dengue virus type 2 (den-2) or kunjin virus (kun) genomes were biotinylated using photobiotin acetate and used as probes for the detection of flavivirus rna in infected vero cells. the viral cdna inserts ranged in length from 0.19 to 2.7 kilobase pairs, and represented segments of the flavivirus genome coding for structural and nonstructural proteins. in spot hybridization assays (hybridization at 60 degrees c) with rna extracted from ...19873031110
[pathogenesis of persistent and chronic forms of tick-borne encephalitis (experimental study)].a long-term experiment was conducted to study various aspects of the pathogenesis of persistent and chronic tick-borne encephalitis (tbe). virological, serological, pathomorphological, electron microscopic and immunofluorescent techniques have been utilized in this study. persistent tbe infection of syrian hamsters examined over the period from 40 days to 2 years was characterized by the presence of virus-specific antigens in the organs and of specific antibodies in the blood serum. the persisti ...19873033955
variation in distribution of the three flavivirus-specified glycoproteins detected by immunofluorescence in infected vero cells.indirect immunofluorescence with rabbit antisera was used to probe the intracellular locations of the antigens of envelope, prm (precursor to structural protein m) and the nonstructural glycoproteins ns 1 (formerly described as nv 3 or scf) specified by the flaviviruses dengue-2 and kunjin. perinuclear staining in various types of foci was prominent for all antigens, and the distribution was influenced by whether cells were fixed with acetone or formaldehyde. staining of golgi-like masses or inc ...19873034209
a comparison of different cloned bluetongue virus genome segments as probes for the detection of virus-specified rna.the seven largest double-stranded (ds) rna genome segments of bluetongue virus (btv) serotype 4 as well as genome segment 8 of btv10 have been cloned into pbr322. the length of the cloned genes indicates that, with the exception of genome segment 1, the entire gene has been cloned in each case. a method is described for isolating different sized cdna transcripts on alkaline sucrose gradients with very good recovery. the eight cloned genes were compared as 32p-labeled probes for the detection of ...19873035788
partial nucleotide sequence of the japanese encephalitis virus genome.approximately 10 kb of the estimated 10.9-kb genome of the japanese encephalitis virus (je; nakayama strain) has been cloned as cdna; the uncloned portion includes 430 bases at the 5'-terminus and 450 bases at the 3'-end. a map of the genome has been developed through nucleotide sequencing and in vivo expression with the escherichia coli expression vector lambda gt11 and immunological identification. sequence results for 4320 nucleotides suggest the je genome organization is very similar to thos ...19873035787
flavivirus replication strategy. 19873035906
a method for predicting murray valley encephalitis in southeast australia using the southern oscillation.clinical cases of murray valley encephalitis in southeast australia have tended to occur in summer and autumn following extended periods of above average rainfall over most of eastern and northern australia. the southern oscillation, an important mode of climatic fluctuations over the indian and pacific oceans, is closely related to eastern and northern australian rainfall. the southern oscillation has been used previously to develop methods for predicting rainfall fluctuations over australia an ...19863036054
experimental infection and horizontal transmission of modoc virus in deer mice (peromyscus maniculatus).deer mice (peromyscus maniculatus) were inoculated with a sublethal dose of a field strain of modoc virus to determine patterns of viral persistence, shedding, and transmission. blood, serum, urine, fecal, and oral swab samples were collected at selected intervals until 63 days postinoculation (pi) after which lung, liver, spleen, kidney, and salivary glands were explanted. viral assays were conducted by intracranial inoculations of suckling mice and antibody titers were determined by the micro- ...19873035240
development of a dot enzyme immunoassay for dengue 3: a sensitive method for the detection of antidengue antibodies.partially purified den3 virus was used as antigen in a sensitive dot enzyme immunoassay (deia) for the detection of antibodies to flavivirus antigens. we describe here the method used to prepare and optimise the antigen-bearing nitrocellulose membranes and present the results obtained from screening 20 acute phase sera from patients shown to have had recent dengue infections by the haemagglutination inhibition (hi) test. sixteen pairs of acute and convalescent sera from dengue-negative patients ...19883058737
the nucleotide sequence of dengue type 4 virus: analysis of genes coding for nonstructural proteins.we recently cloned a full-length dna copy of the dengue type 4 virus genome. analysis of the 5' terminal nucleotide sequence suggested that the three-virion structural proteins are synthesized by proteolytic cleavage of a polyprotein precursor which is encoded in one open reading frame. we now present the remaining sequence of the dengue type 4 virus genome which codes for the nonstructural proteins. the entire genome, which is 10,644 nucleotides in length, contains one long open reading frame w ...19873039728
the experimental infection of horses with murray valley encephalitis and ross river viruses.eleven weanling horses were inoculated with murray valley encephalitis and ross river viruses either by intravenous injection or by the bite of culex annulirostris or aedes vigilax mosquitoes infected orally. five of the 11 horses circulated trace amounts of mve virus for 1 to 5d and they infected 7/408 cx annulirostris which subsequently fed on them. haemagglutination-inhibiting antibody persisted at detectable levels for the 24-week observation period. with ross river virus, only one of 11 hor ...19873038067
[human arbovirus infections in burundi: results of a seroepidemiologic survey, 1980-1982].a serological survey on 623 human sera was conducted in burundi in 1980-1982, in order to evaluate the frequency of arboviral antibodies in the inhabitants of the three main areas: lowlands, central plateau and mountainous ridge. the results show a rather high activity of arboviruses, mainly in the lowlands (34.2% of inhabitants with antibodies). chikungunya virus seems to be the most active arbovirus; the activity of flavivirus is moderate; no trace of activity of yellow fever or west nile viru ...19873038355
separation of functional west nile virus replication complexes from intracellular membrane fragments.flaviviruses encode seven non-structural proteins for which functions have not yet been described. the identification of the viral and possible host proteins which may be involved in flavivirus replication has been impeded by the fact that the viral replication complexes are tightly associated with endoplasmic reticular membranes within infected cells and that in vitro polymerase activity is associated with large membrane fragments. to facilitate further study of flavivirus replication complexes ...19883199103
an enzyme immunoassay to detect australian flaviviruses and identify the encephalitic subgroup using monoclonal antibodies.an antigen-capture enzyme-linked immunosorbent assay (elisa) has been developed to detect antigens of australian flaviviruses in mosquito pools, suckling mouse brain and infected cell culture supernatant fluid. a monoclonal antibody reactive to an epitope on the envelope glycoprotein common to all flaviviruses was used as the capture antibody. purified rabbit igg, produced against murray valley encephalitis (mve) virus, which reacted with eight australian flaviviruses in haemagglutination inhibi ...19873038734
the secondary in vitro murine cytotoxic t cell response to the flavivirus, west nile.a secondary in vitro murine cytotoxic response to the flavivirus, west nile (wnv) is described. cytotoxic activity was obtained from spleen cells of mice primed 7 days previously with 10(6) p.f.u. wnv and boosted in vitro for a further 5 days with wnv-infected stimulator spleen cells. the cells responsible for lysis of wnv-infected target cells were restricted by class 1 h-2 antigens. the k region of the h-2k haplotype and both the k and d regions of the h-2d haplotype were permissive. the cytot ...19883259537
nucleotide sequence of dengue type 3 virus genomic rna encoding viral structural proteins.complementary dnas to the 5' proximal region of the dengue virus type 3 rna were cloned into bacterial plasmids and the nucleotide sequence of 3,000 bases from the 5' terminus of the genome were determined by dna and rna sequencing methods using dideoxy chain-termination reactions. comparison of the nucleotide sequence thus obtained with those of other flavivirus genomes revealed significant homology existing in nucleotide sequence of the flavivirus genomes. when we compared amino acid sequence ...19883227644
prospects for a virus non-structural protein as a subunit vaccine.the design of contemporary vaccines to date has been dependent upon our understanding of the process of stimulation of protective immunity by virion proteins. however, studies with the flaviviruses have demonstrated that protective immunity can be elicited by a non-structural protein, ns1. surprisingly, immunity to infection is stimulated in the absence of neutralizing antibodies. the information concerning ns1-induced immunity is described and is discussed with relevance to the role of the prot ...19883281388
molecular cloning and complete nucleotide sequence of the genome of japanese encephalitis virus beijing-1 strain.the genomic rna of the japanese encephalitis virus (jev) beijing-1 strain was reversely transcribed and the synthesized cdna was molecularly cloned. six continuous cdna clones that cover the entire virus genome were established and sequenced to determine the complete nucleotide sequence of the jev rna. the precise genomic size was estimated as 10,965 bases long. with flanking 95 bases at the 5' and 583 bases at the 3' non-coding regions, one long open reading frame (orf) was revealed encoding a ...19883245133
t cell-mediated cytotoxicity against dengue-infected target cells.a cytotoxic t lymphocyte (ctl) response to dengue virus-infected target cells is described. effector cells were generated in an in vitro secondary culture and appeared to be t cells possessing both the lyt 1.1 and lyt 2.1 surface antigens. a stronger ctl response was noted with the h-2k haplotype compared to h-2d, and h-2 compatibility was required between ctl and target cells. ctl generated showed some cross-reactivity with target cells infected with japanese encephalitis virus (jev), another f ...19883262810
comparative study of various immunomodulators for macrophage and natural killer cell activation and antiviral efficacy against exotic rna viruses.several immunomodulators were compared for immunomodulatory and antiviral activity in b6c3f1 female mice. our results demonstrate that murine recombinant gamma interferon (rifn-g), human recombinant alpha a/d interferon (rifn-a), ampligen (a polyribonucleotide) and cl246,738 modulate nonspecific immunity and are effective antiviral agents in vivo. administration of each of these agents 1 day before cell harvest induced high levels of splenic natural killer (nk) cell activity against yac-1 target ...19883182149
nucleotide sequence and deduced amino acid sequence of the nonstructural proteins of dengue type 2 virus, jamaica genotype: comparative analysis of the full-length genome.the sequence of the 5'-end of the genome of dengue 2 (jamaica genotype) virus has been previously reported (v. deubel, r. m. kinney, and d. w. trent, 1986, virology 155, 365-377). we have now cloned and sequenced the remaining 75% of the genomic rna that encodes the nonstructural proteins. the complete genome is 10,723 bases in length with a single open reading frame extending from nucleotides 97 to 10,269 encoding 3391 amino acids. the 3'-noncoding extremity presents a stem- and loop-structure ...19883388770
association between the ph-dependent conformational change of west nile flavivirus e protein and virus-mediated membrane fusion.the major envelope protein (e) of west nile virus mediates fusion between the membranes of the viral envelope and the target cell at optimum ph values of just below neutrality. the fusion is critical for the entry mechanism, allowing virus to escape from the acidic endosomal compartment. to define the role of the viral e protein in the fusion reaction, the conformational change in e and concomitant change of viral infectivity were studied quantitatively, using protease digestion of the e protein ...19883385406
enhanced neutralization of flavivirus by monoclonal antibodies against negishi virus.ten monoclonal antibodies against negishi virus were classified into 3 groups and 7 types according to the reaction patterns to negishi virus by the hemagglutination inhibition (hi) test and by several kinds of neutralization tests. when kinetic neutralization was applied to these monoclonal antibodies at the same hi titer of 1:64, the initial slope and the persistent fraction of the kinetic curve was varied in each antibody. in the double-kinetic neutralization test, neutralization did not proc ...19883393099
sequence of the structural proteins of tick-borne encephalitis virus (western subtype) and comparative analysis with other flaviviruses.tick-borne encephalitis (tbe) virus (western subtype strain neudoerfl) was cloned and the sequence of 2450 nucleotides of the 5'-terminal region of the genome was determined. by amino acid sequencing and sequence comparisons with other flaviviruses the amino-termini of the structural proteins and protein ns1 were localized. sequence homologies with other flaviviruses were determined and corresponded well to the established serological classification system of the flavivirus family. n-glycosylati ...19883413985
outbreak of febrile illness due to dengue virus type 3 in calcutta during 1983.an epidemic of dengue fever broke out in calcutta between july and august 1983. persons of all age groups were affected with a preponderance of young adults. haemorrhagic manifestations and shock were not observed. virus was isolated from 4 acute phase sera and identified as dengue type 3 (den-3), the first isolation of den-3 virus in calcutta. serotesting with 9 paired blood samples established dengue infection in 7 and a flavivirus group reaction in 2. examination of 36 single sera revealed pr ...19873503397
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
[electron microscopic study of a tick-borne encephalitis virus-infected cell culture exposed to tunicamycin].ultrastructural features of tick-borne encephalitis virus-infected pig embryo cell culture treated with different concentrations of tunicamycin at various intervals after infection were studied electron microscopically. the inhibition of glycosylation did not prevent virion formation in the infected cells. at the same time, treatment with tunicamycin led to marked accumulation of virus particles in cisterns and vacuoles of the golgi complex and to a decrease in the number of virions released int ...19873445587
the primary in vivo murine cytotoxic t cell response to the flavivirus, west nile.a protocol for obtaining cytotoxic t cell responses to the flavivirus west nile (wnv) has been developed in vivo. cba/h (h-2k) mice were immunized with 10(6) p.f.u. wnv intravenously and their spleen cells used directly in cytotoxic assays. this method reliably produced wnv-immune tc cells which showed wnv-specific cytotoxic activity on infected l929 (h-2k) target cells. there was inadequate lysis of infected targets by wnv-immune spleen cells when the m.o.i. was less than 100 p.f.u. wnv, or whe ...19873496425
investigation of a possible yellow fever epidemic and serosurvey for flavivirus infections in northern cameroon, 1984.a cluster of fatal hepatitis cases in northern cameroon in 1984 stimulated a field investigation to rule out an epidemic of yellow fever. a serosurvey of villages in the extreme north of the country, in a sudan savanna (ss) phytogeographical zone, disclosed no evidence of recent yellow fever infection. however, further south, in a guinea savanna (gs) phytogeographical zone, serological evidence was found of endemic yellow fever virus transmission. the results indicate a potential for epidemic sp ...19873501739
analysis of the influence of proteolytic cleavage on the structural organization of the surface of the west nile flavivirus leads to the isolation of a protease-resistant e protein oligomer from the viral surface.in order to analyze the organization of the membrane proteins pre m, m, and e of the west nile (wn) flavivirus we have studied the influence of proteolytic cleavage of intact virus on the structure of these proteins. the amino acid sequence of all proteins is known, all six disulfides present in the viral e protein have been identified, and it has been suggested that the e protein contains regions r1, l1, r2, l2, and r3, which together form the e protein ectodomain followed by a carboxyterminal ...19873629975
a tentative model of formation of structural proteins of tick-borne encephalitis virus (flavivirus).the time course of tick-borne encephalitis virus cell-free protein synthesis was studied by using either [35s]-methionine or formyl[35s]methionyl-trnamet/f as substrates, and the [35s]methionine-labelled products were compared by fingerprinting tryptic peptides. an intermediate in the protein processing, the polypeptide doublet p36/33, was characterized and a tentative model for flavivirus structural protein synthesis and processing was proposed.19863635477
tick-borne encephalitis virus genome. the nucleotide sequence coding for virion structural proteins.rna of a flavivirus, tick-borne encephalitis virus (tbev; strain sofjin), was subjected to reverse transcription and the dna copy was transformed into double-stranded dna by the action of e. coli dna-polymerase i (klenow fragment). this dna was annealed with plasmid pbr322. the recombinant plasmids were cloned in e. coli k802. the nucleotide sequence of the inserts of the clones, coding for region structural proteins c, m, e and nonstructural protein ns1, was determined by the maxam-gilbert meth ...19863709796
sensitive and specific monoclonal immunoassay for detecting yellow fever virus in laboratory and clinical specimens.a solid-phase radioimmunoassay (ria) was developed for the detection of yellow fever (yf) virus in infected cell culture supernatant fluid and clinical samples. the test employed a flavivirus group-reactive monoclonal antibody attached to a polystyrene bead support and a radiolabeled type-specific antibody probe in a simultaneous sandwich ria format. optimal assay conditions specified a 16-h incubation at high temperature (45 degrees c). monoclonal antibody to tetanus toxoid was added to the rad ...19863700596
nucleotide sequence at the 3' end of japanese encephalitis virus genomic rna.japanese encephalitis (je) virus genomic rnas were purified from virions. two hundred nucleotides at the 3' end of je virus genomic rna were directly sequenced by using reverse transcriptase. the nucleotide sequence at the 3' end of the viral rna was conserved among four kinds of je virus strains. the sequence has no au-rich region that is present at the 3' termini of alphavirus rnas. we also compared the nucleotide sequences at the 3' ends of rnas from three different flaviviruses and found sev ...19863727403
[early interaction of the flavivirus west nile virus with mouse macrophage cell line p 388d1: ph-dependent fusion between the virus particles and cell membranes]. 19873672935
a new mechanism for the neutralization of enveloped viruses by antiviral antibody.despite the considerable research that has been carried out into viral neutralization by antiviral antibody, its mechanisms remain poorly understood. cases have been reported in which antiviral antibody can inhibit viral replication without inhibiting the binding and uptake of virus by susceptible cells. it has been shown that many enveloped viruses enter their target cells by endocytosis and are subsequently located in cellular compartments of increasing acidity. with several enveloped viruses ...19863713806
primary structure of the west nile flavivirus genome region coding for all nonstructural proteins.the genome rna of the flavivirus west nile (wn) virus has been transcribed into cdna, the cdna has been cloned, and the nucleotide sequences coding for the structural proteins have been determined (castle et al., 1985; wengler et al., 1985). we have now determined the nucleotide sequence coding for all viral nonstructural proteins which comprises 7929 nucleotides. together with our earlier sequence analyses these data show that a long open reading frame (orf) containing 10,290 nucleotides is pre ...19863753811
the uncoating and infectivity of the flavivirus west nile on interaction with cells: effects of ph and ammonium chloride.infectivity of the west nile virus (wnv; flaviviridae) was inactivated on exposure for brief periods (90 s) to ph 6.6 and below. this inactivation was not due to decreased interaction between cells and acid-treated virus. the rna of [3h]uridine-labelled virus particles prebound to the cell surface before acidic ph treatment underwent rapid uncoating within 1 min at 37 degrees c at the same ph values that inactivated virus particles. the uncoating of [3h]uridine-labelled virus particles was also ...19863746254
protection against yellow fever in monkeys by immunization with yellow fever virus nonstructural protein ns1.immunization of monkeys with yellow fever virus-specified nonstructural protein ns1 resulted in protection against fatal hepatitis as well as marked reduction in the magnitude of viremia after subcutaneous challenge with yellow fever virus. the results may be relevant to the design of possible subunit or recombinant flavivirus vaccines.19863783816
the effect of ph on the early interaction of west nile virus with p388d1 cells.the interaction between the flavivirus west nile virus (wnv) and cells of the mouse macrophage-like cell line, p388d1, was assayed by transmission electron microscopy, by following the association of [35s]methionine-labelled virus with cells, and by using a radiobinding assay with an 125i-labelled f(ab')2 fragment of a monoclonal antibody directed against the major viral envelope surface glycoprotein. using electron microscopy, both fusion and endocytosis were observed at ph 6.4, but at ph 8.0 o ...19863783128
dengue 3 virus transmission in africa.the first known transmission of dengue 3 virus in africa was documented by virus isolation during an epidemic of dengue-like illness in pemba, mozambique, in late 1984 and early 1985. dengue 3 virus was the only serotype isolated. most patients appeared to be experiencing secondary flavivirus infections, but whether this was the result of previous dengue, yellow fever, or other flavivirus infection is not known. two cases of hemorrhagic disease with shock and death were associated with the epide ...19863789276
[encephalitic syndrome caused by flavivirus diagnosed after return from a voyage to south india: probably dengue with neurological manifestations].the authors report the case of a flavivirus encephalitis (probable dengue) in a 70 year old female, occurring twenty days after a fewer of unknown origin, contracted in the south of india. most of the cases of such encephalitis have been reported from children, but they may occur also in adults.19863802313
analysis of disulfides present in the membrane proteins of the west nile flavivirus.recently the primary structure of the structural proteins of the flaviviruses west nile (wn) virus (castle et al., 1985; wengler et al., 1985) and yellow fever (yf) virus (rice et al., 1985) have been determined. as a first step in a further characterization of the organization of the structural proteins we have now studied the disulfide bridges present in the wn virus membrane proteins. all three membrane proteins, pre m, m, and e, were analyzed. the results obtained can be summarized as follow ...19873811228
[synthesis and membrane-dependent processing of a precursor of tick-borne encephalitis virus (flavivirus) structural proteins in cell-free systems].conditions that permitted cell-free synthesis of at least one of the non-structural, in addition to two-structural, polypeptides of tick-borne encephalitis virus have been found. the time course of accumulation of virus-specific polypeptides in extracts of krebs-2 cells and reticulocyte lysates as well as the peptide maps of the products synthesised were studied. a model of generation of viral structural polypeptides has been proposed, according to which a common precursor of these proteins whil ...19863773888
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