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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
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
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
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
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
[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
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
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
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
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
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
genetically controlled resistance to virus infections of the central nervous system. 19853014607
[meningoencephalitis caused by the st. louis encephalitis virus]. 19853022104
replication strategy of kunjin virus: evidence for recycling role of replicative form rna as template in semiconservative and asymmetric replication.only three forms of kunjin virus-specified rna were isolated from cytoplasm early after the latent period (about 15 hr) viz., 44 s genomic-sized single-stranded rna, 20 s double-stranded "replicative form" (rf), and 20-28 s partially ribonuclease-resistant (about 70%) "replicative intermediate" (ri). the rf and ri were resolved by electrophoresis in aqueous-agarose gel only following licl fractionation. the ri did not enter urea-polyacrylamide gels. after denaturation of untreated or rnase-treat ...19852578239
epitopic analysis of antigenic determinants on the surface of dengue-2 virions using monoclonal antibodies.the relative binding sites of dengue serotype-specific, dengue subcomplex-specific, dengue complex-specific, flavivirus subgroup-reactive, and flavivirus group-reactive monoclonal antibody preparations were identified by using competitive antibody binding assays. a dengue complex-specific epitope, capable of mediating infection enhancement, was identified on a 20,000 dalton protein found on intracellular virions. the other epitopes were assigned relative positions on the e glycoprotein by compet ...19852578750
examination of the immunological relationships between flaviviruses using yellow fever virus monoclonal antibodies.monoclonal antibodies prepared against vaccine strains of yellow fever (yf) virus were initially characterized by fluorescence microscopy of vero cells infected with yf virus strain 17d. when similarly tested against representatives of all flavivirus subgroups, the antibodies produced a wide spectrum of reactions ranging from the monospecific to the broadly cross-reactive; at least five antigenic domains in the yf virus envelope glycoprotein were identified. monoclonal antibodies differentiated ...19852410549
temperature-sensitive mutants of japanese encephalitis virus.ten stable temperature-sensitive mutants of japanese encephalitis virus were isolated after mutagenesis by growth of cloned wild-type virus in the presence of the nucleic acid precursor analogs 5-fluorouracil and 5-azacytidine. mutants were selected which grew at least 100-fold better at 33 degrees c than at 41 degrees c. the 5-fluorouracil was found to be more effective at inducing temperature-sensitive mutations than was 5-azacytidine. analysis of the virus-specific rna and proteins synthesize ...19852410633
studies on the antigenic structure of japanese encephalitis virus using monoclonal antibodies.the antigenic relationships among 11 strains of japanese encephalitis (je) virus were analyzed by using monoclonal antibodies (narma) against the nakayama-rfvl strain in hemagglutination-inhibition (hi) and neutralization (nt) tests. of the 14 je virus-specific hi antibodies, all except narma 5 showed nt reactivity with the homologous strain. the hi and nt titers of these antibodies were not parallel. the 14 antibodies included the following characteristic antibodies: narma 3 is a species-specif ...19852419739
multisite monoclonal immunoassay for dengue viruses: detection of viraemic human sera and interference by heterologous antibody.a monoclonal radioimmunoassay (ria) was developed for detection of dengue virus in infected cell culture fluids and blood samples from dengue patients. antibodies used to construct the ria were selected on the basis of high binding avidity, the demonstration of synergism in competitive binding assays and empirical trials with different antibody combinations. optimal binding of all four dengue virus serotypes was achieved by use of a flavivirus group-reactive and a dengue virus complex-reactive a ...19862420923
the cap structure of simian hemorrhagic fever virion rna.the molecular weight of simian hemorrhagic fever virus rna is 4.19 +/- 0.53 x 10(6) as determined by electron microscopy. its base composition is 19.5 +/- 0.3 a, 33.3 +/- 0.3 u, 26.7 +/- 0.9 g, and 19.7 +/- 0.3 c per 100 nucleotides. the rna of simian hemorrhagic fever virus contains a single type i cap per molecule, in the form m7g(5')ppp(5')am.19862421482
epitope mapping of flavivirus glycoproteins. 19862428213
antigenic comparison of envelope protein e between japanese encephalitis virus and some other flaviviruses using monoclonal antibodies.the antigenic relationships between japanese encephalitis (je) virus and several other flaviviruses have been investigated using anti-je virus monoclonal antibodies (mabs). seventeen mabs directed against envelope protein e of je virus were characterized and divided into eight mab groups based on reactivity patterns in haemagglutination inhibition test, neutralization (n) test, elisa and competitive binding assay with je virus. the results suggest the existence of at least eight epitopes on the ...19862432163
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
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
[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
[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
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: 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
genetically controlled resistance to flaviviruses within the house mouse complex of species. 19863015496
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
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
[detection of the koutango virus (flavivirus, togaviridae) in somalia]. 19863018465
[results of studying foci of arbovirus infections in the southern maritime territory]. 19863018466
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
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
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
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
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
mosquito-borne virus diseases of man in southern africa. 19863022406
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
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
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
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
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
[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
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
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
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
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
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
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
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
virus isolations from mosquitoes collected during the 1982 japanese encephalitis epidemic in northern thailand.from 16 june to 15 august, 1982 cdc light traps were used to collect mosquitoes in the province of kamphaengphet, n. thailand. 353,042 mosquitoes comprising 59 species were collected and identified, and 345,173 were placed in pools for attempted virus isolation by inoculation of c6/36 aedes albopictus mosquito cell cultures. viruses were isolated from 63 mosquito pools. these comprised 56 flaviviruses, identified as 35 isolates of japanese encephalitis (je) virus strains, 18 strains of tembusu ( ...19862885948
identification of flaviviruses by the single-radial-haemolysis test. 19862883117
genetic differentiation of murray valley encephalitis virus in australia and papua new guinea.the genetic relatedness of ten murray valley encephalitis virus (mve) isolates from australia has been examined by comparing haeiii and taqi restriction digest profiles of cdna to virion rna. the isolates were from the murray valley region of south-eastern australia and from the ord river region of western australia and spanned a period of 23 years (1951-1974). the isolates generated closely similar restriction digest profiles. the extent of similarity suggested that the level of nucleotide sequ ...19862884985
blood value changes in flavivirus-inoculated macaca fascicularis monkeys.blood values were analysed in eighteen cynomolgus monkeys on pre-and post-neurovirulence testing of dengue-2 and yellow fever vaccine viruses, dengue-2 parental and japanese encephalitis viruses. certain changes between blood chemistry, hematology and serology were observed and briefly discussed.19862874612
changes of natural killer cell activity in different mouse lines by acute and asymptomatic flavivirus infections.effect of certain flaviviruses on the activity of mouse natural killer (nk) cells was investigated using the classical mouse splenocyte system and yac-1 cells for demonstration of nk cell cytotoxicity. infection of mice with langat and west nile (wn) viruses was accompanied by temporary activation of nk cells. in mice infected with tick-borne encephalitis (tbe) virus the stimulation phase of nk cell cytotoxicity on days 2-4 post-infection (p.i.) was followed by suppression of their activity. as ...19862876611
[arbovirus-vector-vertebrate cycles in madagascan forests]. 19862879516
application of enzyme immunoassay on infected cells (eia-ic) for arboviruses.comparative titrations of alpha-, flavi- and bunyamwera viruses were made by eia-ic and according to cytopathic effect (cpe). specific enzymatic reactions appeared earlier and in higher titres than cpe. the titres of dengue type 1, mayaro, powassan and langat viruses measured by eia-ic were comparable to those measured by intracerebral inoculation of mice. the cross-reactivity testing of eia-ic among alphaviruses (chikungunya, sindbis and mayaro), flaviviruses (japanese encephalitis, murray vall ...19862881468
recent advances in the molecular biology of flaviviruses. 19862824939
ph-dependent fusion between the flavivirus west nile and liposomal model membranes.fusion between purified [3h]uridine-labelled west nile virus (wnv) particles and liposomes containing rnase, was assayed by degradation of the viral rna to trichloroacetic acid-soluble material. fusion of virus with liposomes containing phosphatidylcholine, phosphatidylethanolamine, sphingomyelin and cholesterol (at a molar ratio of 1:1:1:1.5) was found to be dependent on ph with maximum fusion occurring at ph 6.7 and below. at ph 6.6 fusion was rapid and was essentially complete within 2 min at ...19863944582
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
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
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
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
[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
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
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
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
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
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
[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
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
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
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
nucleotide sequence of the 5'-terminal untranslated part of the genome of the flavivirus west nile virus.we have determined the nucleotide sequence of the 5'-terminal untranslated region of the 42 s genome rna of the flavivirus west nile virus by primer extension. these analyses make our primary structure determination of this genome, which comprises a total number of 10,960 nucleotides, complete. some implications of our data concerning the structure of flavivirus-specific nucleic acids and the initiation of translation of wn virus-specific rna are discussed.19873813889
william c. reeves and arbovirus research in australia.william c. reeves was invited to australia in 1952 to take part in field studies of murray valley encephalitis. the results of his work led to various hypotheses which directed arbovirus research in australia for a generation. that and the people he influenced in australia made him a major figure in the development of australian arbovirus research.19872825554
involvement of microtubules in kunjin virus replication. brief report.induction of microtubulin paracrystals (pc) by kunjin (kun) virus occurred after 15 hours post-infection and were often associated with convoluted membranes (cm) and virus particles. vinblastine sulphate which disrupts microtubulin, had an inhibitory effect on the virus production when added during the viral latent period. when infected samples were extracted with triton x-100 and analysed by sds-page, four viral proteins were observed.19872825618
california serogroup and powassan virus infection of cats.one hundred and seventy five sera from cats in ontario, canada, were tested for hemagglutination inhibition (hi) antibodies to three arboviruses; namely, powassan (pow) of the flavivirus serogroup, and snowshoe hare (ssh) and jamestown canyon (jc) viruses of the california (cal) serogroup. all sera were negative for antibodies to pow virus. twelve cats possessed cal serogroup antibodies including 3 with antibodies to ssh alone, 6 with antibodies to jc alone, and 3 with antibodies to both ssh and ...19872825952
haemagglutination-inhibiting antibodies against arboviruses of the families togaviridae and bunyaviridae in birds caught in southern moravia, czechoslovakia.a total of 295 birds belonging to 19 species of 7 families of wild passeriformes were examined by haemagglutination-inhibition test. the birds were caught for an international research program "balt" at the time of autumn migration (august-september 1984). their blood sera were examined for antibodies against 6 arbovirus antigens of the genera alphavirus (sindbis-sin) and flavivirus (tick-borne encephalitis-tbe, west nile-wn) and family bunyaviridae (tahyna-tah, calovo-cvo and bhanja-bha). antib ...19872822552
flavivirus-specific murine l3t4+ t cell clones: induction, characterization and cross-reactivity.murine t cell clones specific for the kunjin (kun), west nile (wn) and murray valley encephalitis (mve) flaviviruses were generated in vitro following priming in vivo. clones were isolated by limiting dilution and maintained in culture with antigen stimulation and interleukin-2(il-2). the cells were characterized as having the thy 1+, l3t4+ and lyt 2- phenotype by immunofluorescence. all clones proliferated strongly and secreted high levels of il-2 and il-3 in response to homologous antigen. bot ...19872822843
the effect of gold sodium thiomalate in adult swiss/a2g mice infected with togaviruses and flaviviruses.treatment of adult mice with gold sodium thiomalate made the normally non-lethal semliki forest virus and sindbis virus infections lethal and increased the virulence of langat and west nile viruses. these changes were associated with an enhanced virus invasion of the brain. depression of the humoral antibody response was not observed.19872822844
molecular biology of the flaviviruses.an overview of the molecular biology of the flaviviruses is presented. the members of this virus family are enveloped positive-strand rna viruses capable of causing a number of important human diseases.19872856425
susceptibility of mammalian cell cultures to infection with arbo-togaviruses.six alphaviruses and four flaviviruses were inoculated intracerebrally into 1 to 3 days old suckling mice. all mice developed cns diseases and died 2-5 days post-infection. it appeared that alphaviruses were more virulent than flaviviruses since they brought death to the injected mice earlier than the flaviviruses. the susceptibilities of nine different culture cells to those viruses were also investigated using plaque assay. bhk-21 cells produced clearer plaques and were more sensitive than oth ...19872835211
detection of dengue virus rna using nucleic acid hybridization.conditions for using slot-blot nucleic acid hybridization to quantitatively detect dengue-2 virus using a radiolabelled cdna probe, pvv17, were determined. as little as 11 plaque-forming units of virus were detected using a hybridization mixture without formamide and performing the test at 70 degrees c. while predominantly serotype-specific using stringent (65 degrees c) washing conditions, the probe detected all four dengue virus serotypes using astringent (28 degrees c) washing conditions. no ...19872881940
overwintering mechanisms of mosquito-borne arboviruses in temperate climates.it can be concluded from the data cited that transovarial transmission is a plausible explanation for the overwintering of mosquito-borne bunyaviruses of the california serogroup. vertical transmission of mosquito-borne flaviviruses could explain the overwintering of this group of viruses, but this is far from having been established. at present, the mechanism by which mosquito-borne alphaviruses pass the winter is obscure.19872891312
potiskum virus: enhancement of replication in a macrophage-like cell line.replication of potiskum virus was studied in p388d1 macrophage-like cell line in the presence and absence of subneutralizing concentrations of specific antiviral antibody. the cultures were infected at multiplicities of infection (moi) ranging from 0.4 to 0.0004. the virus replicated to high titres at all moi tested, but there was an enhancement of virus replication in cultures supplemented with the antibody. enhancement of replication was moi dependent, the highest ratios being obtained in cult ...19872894139
formation of autoimmune effectors after transfer of virus-induced autoreactive precursors to syngeneic intact receptor animals.we verified the assumption that autoimmune responses underlie immunosuppression developing in the course of virus infection. it has been shown by adoptive transfer that administration of langat-virus-induced autoreactive lymphocytes (arl) to the syngeneic recipient is followed by accumulation of autoreactive effectors (ae) eliciting a graft-verus-host reaction (gvhr) in the syngeneic system (aegvhr). in addition, cytotoxic t-lymphocytes (aec) appeared against the syngeneic macrophages. this effe ...19872894142
[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
[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
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