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Showing papers on "Dengue virus published in 1986"


Book ChapterDOI
TL;DR: This chapter surveys the historical background to the phenomenon of antibody-dependent enhancement (ADE) of viral infectivity and considers the two mechanisms that are known to exist.
Abstract: Publisher Summary This chapter surveys the historical background to the phenomenon of antibody-dependent enhancement (ADE) of viral infectivity and considers the two mechanisms that are known to exist. It updates the earlier review of Halstead that was concerned solely with enhancement mediated by cellular receptors for the Fc portion of immunoglobulin molecules (FcR), and it extends the mini review of Porterfield and Cardosa that also took note of the second enhancement pathway mediated by receptors for components of the complement system. The first reports of ADE provide convincing documentation that the phenomenon is not an observational artifact. The studies of Halstead and collaborators were conducted against a background of the clinical problem of dengue hemorrhagic fever and the dengue shock syndrome that appeared to be unique. They also put forward the view that ADE of viral replication by non-neutralizing antibody might be a rather general biological phenomenon. The underlying concept is simple. Cells bearing receptors for the Fc portion of immunoglobulin will bind IgG. Complexes of virus and antibody will bind to the Fc receptor. If the antibody is non-neutralizing, the virus will be able to infect the FcR-bearing cell which is normally poorly permissive to viral infection. Observations in several laboratories on a wide range of different viruses have established that the phenomenon of ADE is not confined to dengue viruses. Primary macrophages carry FcR and some observations on ADE in primary macrophages in different states of activation are considered in the chapter.

206 citations


Journal ArticleDOI
01 Nov 1986-Virology
TL;DR: Comparison of sequence homology of structural proteins suggests that dengue virus is more closely related to WN virus than to YF virus or Murray Valley encephalitis virus, and analysis of the extreme 5'- and 3'-terminal nucleotides of the d Dengue virus genome revealed sequences that may be involved in transcription, replication, and packaging of viral RNA.

201 citations


Journal ArticleDOI
TL;DR: Studies in paired sera confirmed the presence of recent infection by dengue virus type 1 in Aedes albopictus cell strain from sera of patients living in the Nova Iguaçu county, by Rio de Janeiro.
Abstract: Dengue virus type 1 has been isolated in Aedes albopictus cell strain, from sera of patients living in the Nova Iguacu county, by Rio de Janeiro. The clinical picture was characterized by fever, headache, retrobulbar pain, backache, pains in the muscles and the joints and prostration. Studies in paired sera confirmed the presence of recent infection by dengue virus type 1. The outbreak reached adjacent areas, including Rio de Janeiro city (May, 1986).

184 citations


Journal ArticleDOI
01 Dec 1986-Virology
TL;DR: 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.

167 citations


Book ChapterDOI
01 Jan 1986
TL;DR: Ultimately, flavivirus biology and pathogenesis will be understood in terms of viral gene expression, virus receptor—host cell membrane interactions, biochemical alterations in host cells, physiological responses, and immune and nonimmune mechanisms that control virus replication and virus spread.
Abstract: Among arthropod-borne and related viruses, the Flaviviridae are medically the most important group and biologically one of the most intriguing. Elucidation of perplexingly complex virus- and host-specified factors that underlie virulence and pathogenesis has lagged behind other areas of virology, and the available information is largely descriptive. Ultimately, flavivirus biology and pathogenesis will be understood in terms of viral gene expression, virus receptor—host cell membrane interactions, biochemical alterations in host cells, physiological responses, and immune and nonimmune mechanisms that control virus replication and virus spread, subjects to which other chapters in this book are devoted. There will remain, however, a need to understand and synthesize this information with observations relating to infection at the level of the intact organism (virus, vector, and host) and of populations of organisms in nature. It is at these levels that the phenomena that require explanation first present themselves.

143 citations


Journal ArticleDOI
01 Jan 1986-Gene
TL;DR: The significant homology between these two viruses in the regions coding for the non-structural proteins NS3 and NS5 suggests an important role for these two proteins in the life cycle of these viruses.

119 citations


Journal ArticleDOI
TL;DR: The clinical presentation and course of patients infected with dengue virus were most consistent with classicdengue fever, and both d Dengue 1 and 2 must be considered causes of acute fever in East Africa.
Abstract: One hundred consecutive patients admitted to the Port Sudan Hospital with a temperature ≥ 100°F were evaluated. Enteric fever was diagnosed in 19 patients and malaria in 13. Virologic studies identified 21 cases of dengue infection. One dengue 1 and 17 dengue 2 infections were diagnosed by viral isolation. Three untyped dengue infections were identified serologically. The clinical presentation and course of patients infected with dengue virus were most consistent with classic dengue fever. There was no evidence of hemorrhagic phenomena or shock in any of the dengue-infected patients. Both dengue 1 and 2 must be considered causes of acute fever in East Africa.

63 citations


Journal ArticleDOI
30 Oct 1986-Virology
TL;DR: Signature analysis provides a more rapid and simpler means than RNA fingerprinting of monitoring changes or new introductions of dengue virus populations in a geographic region and revealed striking antigenic differences.

51 citations


Journal ArticleDOI
TL;DR: Se hace un resumen de las actividades que desarrolla el Laboratorio de Virologia del Instituto Nacional de Salud para apoyar el diagnostico de esta enfermedad en el pais y sobre the actividad del virus de fiebre amarilla en focos selvaticos vecinos a ciudades altamente infestadas.
Abstract: In 1947 the Colombian goverment established a campain for the erradication of Aedes aegypti in the country, following the recomendations of the Pan American Sanitaq Bureau. This campaign caused the disappearance of endemic dengue for approximately 20 years until it reappeared in explosive form with the epidemic of dengue 2 on the Atlantic Coast (1971-1972), followed by two documented large epidemics of dengue 3 (1975-1977) and dengue 1 in 1978. A summary is given of the activities developed by the virus laboratory of the National Institute of Health to aid the diagnosis of this disease in the country, including the first isolation of dengue 4 virus in 1982, the activity of dengue 1 ,- 2 and 4 viruses to the present time, the clinical and virological findings of a hemorragic case associated to dengue virus infection and a short report of the epidemic of Tumaco on the Pacific Coast, in which the simultaneous activity of dengue 1 and dengue 2 viruses was demonstrated. Finally, information is given on the current status of Aedes aegypti infestation in the country and about the activity of yellow fever virus in sylvatic foci close to heavily infected cities, detected in the month of January, 1987 in Colombia.

43 citations


Journal ArticleDOI
Sai Kit Lam1, C.B. Chew1, G.K. Poon1, S. Ramalingam1, S.C. Seow1, T. Pang1 
TL;DR: This work describes a method using intracerebral inoculation of immobilized fourth instar of Toxorhynchites splendens larvae for the isolation of dengue viruses from clinical specimens which yields results within a few days following incubation at 32 degrees C.

38 citations


Journal ArticleDOI
TL;DR: Human peripheral blood lymphocytes (PBL) of non-immune donors produced interferon (IFN) when cultured with dengue virus-infected cells, indicating that PBL produce IFN in response to dengu virus- infected cells and that the production of IFN by PBL is due to stimulation of PBL by denge virus- Infected cells.
Abstract: Summary Human peripheral blood lymphocytes (PBL) of non-immune donors produced interferon (IFN) when cultured with dengue virus-infected cells. IFN was detected as early as 2 h after exposure of PBL to dengue virus-infected cells, and the titres reached a maximum by 16 h of incubation. Dengue virus-infected cells treated with glutaraldehyde, which produced no infectious dengue virus, also induced IFN. These results indicate that PBL produce IFN in response to dengue virus-infected cells and that the production of IFN by PBL is due to stimulation of PBL by dengue virus-infected cells. Characterization of IFN-producing PBL with monoclonal antibodies demonstrated that the predominant producing cells were contained in M1+ and T3- subsets, and that the Leu11+ subset contains some IFN-producing cells. The IFNs that were produced by the PBL exposed to dengue virus-infected cells were analysed by radioimmunoassay employing monoclonal antibodies specifically to detect IFN-α or IFN-γ. IFN-γ as well as IFN-α was produced by PBL exposed to dengue virus-infected cells. Both IFN-α and IFN-γ were predominantly produced by PBL contained in M1+ and T3- subsets. The observation that PBL of non-immune donors produced IFN-γ as well as IFN-α in response to dengue virus-infected cells is of interest in view of the immunoregulatory roles of IFNs and the hypothesis that the complications of dengue virus infection (haemorrhagic fever and shock) may be due to immunopathology.

Journal ArticleDOI
TL;DR: The recognition of unique dengue isolates should allow the selection of reference strains and vaccine candidate strains which will induce antibodies that are equally effective in neutralizing viruses from all geographic areas.
Abstract: Twenty-one dengue (DEN) viruses isolated from the Caribbean (Dominica and Jamaica) during the 1981–1982 epidemic year were distinct serological and genetic variants of DEN-4 virus. These isolates were clearly identified as DEN-4 viruses using type-specific monoclonal antibodies in indirect immunofluorescence assays. However, they either were not neutralized, or were neutralized poorly using hyperimmune mouse ascitic fluids (HMAF) or rhesus monkey serum directed against the H-241 prototype strain of DEN-4 virus isolated in the Philippines in 1956. HMAF prepared against a representative Caribbean isolate, however, neutralized with similar effectiveness the homologous virus, the H-241 prototype strain, and virus strains isolated from the Pacific and Southeast Asian areas from 1973 to 1984. The Caribbean isolate exhibited no more than 30% and 16% oligonucleotide spot homology with the H-241 and Bangkok viruses, respectively, by RNA fingerprint analysis, while demonstrating 82% and 89% homology with the Gilbert and Niue Island isolates, respectively. The isolation of dengue viruses which are serologically and genetically distinct from the prototype virus emphasizes the need for continued dengue virus surveillance. The recognition of unique dengue isolates should allow the selection of reference strains and vaccine candidate strains which will induce antibodies that are equally effective in neutralizing viruses from all geographic areas.

Journal Article
TL;DR: The results of the present study indicate that the PBL that are active in lysing dengue virus-infected cells are heterogeneous and are contained in Leu11+ and T3+ subsets.
Abstract: Non-immune human peripheral blood lymphocytes (PBL) lyse dengue virus-infected cells to a greater degree than uninfected cells. In the present study, the PBL active in lysing dengue virus-infected Raji cells are characterized using monoclonal antibodies and are compared to lymphocytes that lyse K562 cells. Leu11+ cells lyse dengue virus-infected cells and K562 cells. Leu11- cells lyse dengue virus-infected cells, but not K562 cells. In the Leu11+ fraction, Leu11+ Leu7- cells are more active than Leu11+ Leu7+ cells in lysing dengue virus-infected cells. T3+ cells also lyse dengue virus-infected cells, but they do not lyse K562 cells. T3- cells lyse both target cells. These results, along with the observation that Leu11+ cells and T3+ cells are different subsets of PBL, indicate that the PBL that are active in lysing dengue virus-infected cells are heterogeneous and are contained in Leu11+ and T3+ subsets. Leu11+ cells are more active than T3+ cells. Leu11+ cells are active in lysing dengue virus-infected cells by antibody-dependent cell-mediated cytotoxicity, whereas T3+ cells are not active.

Journal Article
TL;DR: During the summer of 1981, an outbreak of dengue occurred on Liouchyou Shiang, an islet about 15 km.
Abstract: During the summer of 1981, an outbreak of dengue occurred on Liouchyou Shiang, an islet about 15 km southwest of Taiwan More than 12, 500 people, approximately 80% of the inhabitants, were estimated to be affected in this epidemic which had been the first dengue outbreak in Taiwan since 1945 Neither shock nor fatal case was found The epidemic subsided in October and there was no confirmed dengue case in Taiwan from 1982 to 1985 All the 21 virus strains isolated from the blood of patients were now identified as type 2 dengue virus and believed to be the first isolation in Taiwan The pathogen was probably introduced from the Philippines

Journal Article
TL;DR: It seems that dengue viruses provoke a transitory alteration in the humoral regulation of thrombopoiesis which possibly may be the consequence of the lymphoid tissue damage and contributes to the appearance of hemorrhagic complications.
Abstract: The causes of thrombocytopenia, one of the most dangerous symptoms in the course of dengue hemorrhagic fever (DHF), are not yet clear. We studied patients with DHF (dengue virus type 2), grouped according to days of illness, platelet counts, serum thrombopoietin (Tpo) levels, and bone marrow differential counts. During the thrombocytopenic phase of disease (3rd-8th days) the Tpo levels were not increased in spite of low platelet counts. Beginning from the 6th-7th day in some patients, a rapid increase in Tpo levels was observed, followed by a rise in the platelet counts. By the 9th-11th days all patients studied were in this phase of convalescence. The bone marrow specimens obtained on the 6th-10th days of illness showed a megakaryocytic hyperplasia in 60% of cases. It seems that dengue viruses provoke a transitory alteration in the humoral regulation of thrombopoiesis which possibly may be the consequence of the lymphoid tissue damage. This extends the thrombocytopenic state and contributes to the appearance of hemorrhagic complications.

Journal ArticleDOI
TL;DR: The antigen capture RIA appears useful as a rapid diagnostic technique for dengue surveillance and was more frequently detected in cases of primary infection than in Cases of superinfection.
Abstract: 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 antibody as radiolabelled probe. A 'simultaneous sandwich' format and prolonged (18 h) incubation at 37 degrees C yielded optimal results. The limit of sensitivity of the RIA for detection of dengue type 2 virus was 2.7 log10 mosquito 50% infectious doses (MID50). The assay was tenfold more sensitive for dengue type 2 than for dengue types 1 and 3 viruses and 100-fold more sensitive than for dengue type 4 virus. Specificity, assessed using over 500 disease control human sera, was increased by addition of monoclonal anti-tetanus blocking antibodies, resulting in a false positive rate of only 0.2%. Heterologous dengue virus antibodies were shown to inhibit the RIA in assays performed with artificial immune complexes. Acute phase human sera containing 10(4.2) to 10(7.6) MID50 but no detectable antigen by RIA, were also shown to inhibit binding of the homologous dengue virus serotype; this effect was attributed to heterologous antibody from a prior infection. Among 116 viraemic sera from dengue patients, the RIA was positive in 43 to 47% of patients with dengue type 1, 2 or 3 infections but in only 10% of the dengue type 4 cases. Virus was more frequently detected in cases of primary infection (54%) than in cases of superinfection (16%). Despite the limitations imposed by immunological interference, the antigen capture RIA appears useful as a rapid diagnostic technique for dengue surveillance.

Journal ArticleDOI
TL;DR: The present experimental system can be used to detect anti‐DEN 2 IgE antibody in mice and it was demonstrated that the antibody was cytophilic and heat‐labile.
Abstract: Mice were immunized with dengue type 2 virus (DEN 2) under a schedule favoring the production of IgE antibody The antibody obtained could sensitize peritoneal resident mast cells both in vitro and in vivo so that the sensitized cells were degranulated and released histamine on challenge with the DEN 2 antigen It was also demonstrated that the antibody was cytophilic and heat-labile The above observations suggest that the present experimental system can be used to detect anti-DEN 2 IgE antibody in mice

Journal ArticleDOI
TL;DR: Seroepidemiologic investigations showed that 74% of healthy individuals in the epidemic area had antibody to d Dengue virus compared to 54% in an area where epidemic dengue had occurred in 1978, and less than or equal to 8% in nonepidemic areas.
Abstract: Virologic and seroepidemiologic studies were carried out during an epidemic of dengue fever on Hainan Island in 1980 Dengue 3 virus was isolated from 46 of 77 acute phase sera and from 1 of 10 pools of adult Aedes aegypti Dengue 1 virus virus was isolated from a single acute phase serum Seroepidemiologic investigations showed that 74% of healthy individuals in the epidemic area had antibody to dengue virus compared to 54% in an area where epidemic dengue had occurred in 1978, and less than or equal to 8% in nonepidemic areas There were no significant differences in antibody prevalence for different sex and age groups

01 Jan 1986
TL;DR: A highly specific, sensitive, and economical hemadsorption immunosorbent technique for the detection of dengue-specific immunoglobulin M (IgM) antibody, which is specific, inexpensive, highly reproducible, and simple to perform.
Abstract: sera fromsecondary dengue infections. Additionally, 32of76single serafrompatients were positive fordengue IgM;these serawerepreviously uninterpretable bythehemagglutination inhibition test, asonly asingle serum specimen was available. No false-positive results were obtained withsera thatwere negative bythe hemagglutination inhibition testfordengue virus. Crudedengue virushemagglutinin preparations couldbe usedwithout purification. Dengue-specific IgGdidnotinterfere withtheresults, nor was thereany cross-reactivity between dengue hemagglutinins andIgMspecific forother viruses. Somecross-reactivity ofthe dengue-specific IgMwas observed withJapanese encephalitis virus hemagglutinins, butthis didnotpresent any problems intheinterpretation ofresults. Thistest isspecific, inexpensive, highly reproducible, andsimple to perform. Denguefever (DF)anddengue hemorrhagic fever (DHF) contribute significantly tomorbidity andmortality inmany parts ofthetropical world. An important factor inthe management ofDF andDHF andintheprevention and control ofoutbreaks istheavailability ofarapid, sensitive, specific, andeconomical laboratory diagnostic test toconfirmdengue infection. However, currently available tests based onvirus isolation andserology arestill unsatisfactory inthis regard. Withregard toserology, mostlaboratories use conventional methods suchashemagglutination inhibition (HAI), thecomplement fixation test, andtheneutralization test todiagnose dengue virus infections. Theseserological tests areofdiagnostic importance ifaseroconversion or fourfold orgreater rise inantibody titers between acute- and convalescent-phase seracanbedemonstrated. Veryoften thecollection ofpaired seraisnotwellspaced toshowarise intiter ofdiagnostic value, oronlyasingle serumspecimen iscollected. Itwouldthusbeofvalue todevelop aspecific andeconomical testwhichwouldbepositive early inthe infection and,preferably, require onlyasingle specimen. Thedetection ofdengue-specific immunoglobulin M (IgM) maybeconsistent withthese considerations. Because IgMgenerally appears early intheonsetof disease andisrelatively transient, its detection wouldbean indication ofanongoing orrecent infection. Conventional methods ofdetecting IgMantibody require thephysical separation ofIgMfromIgG.Thesemethods, besides being costly, aretedious toperform andtime-consuming. A significant advance intherapid diagnosis ofviral infections was thedevelopment ofsolid-phase immunoassays forthedetection ofvirus-specific IgMantibody (4,6,15,16). Thebasis

Journal ArticleDOI
TL;DR: In this article, the authors developed a highly specific, sensitive, and economical hemadsorption immunosorbent technique for the detection of dengue-specific immunoglobulin M (IgM) antibody.
Abstract: We developed a highly specific, sensitive, and economical hemadsorption immunosorbent technique for the detection of dengue-specific immunoglobulin M (IgM) antibody. The technique is based on the reaction of human sera with anti-human IgM immobilized onto a solid phase followed by the detection of dengue-specific IgM by the addition of a known quantity of dengue virus hemagglutinin and goose erythrocytes. Dengue-specific IgM-positive sera showed hemadsorption. IgM antibody specific for dengue virus was detected in 22 of 39 (56%) convalescent-phase sera from primary dengue infections and 8 of 10 (80%) convalescent-phase sera from secondary dengue infections. Additionally, 32 of 76 single sera from patients were positive for dengue IgM; these sera were previously uninterpretable by the hemagglutination inhibition test, as only a single serum specimen was available. No false-positive results were obtained with sera that were negative by the hemagglutination inhibition test for dengue virus. Crude dengue virus hemagglutinin preparations could be used without purification. Dengue-specific IgG did not interfere with the results, nor was there any cross-reactivity between dengue hemagglutinins and IgM specific for other viruses. Some cross-reactivity of the dengue-specific IgM was observed with Japanese encephalitis virus hemagglutinins, but this did not present any problems in the interpretation of results. This test is specific, inexpensive, highly reproducible, and simple to perform.

Journal ArticleDOI
TL;DR: The combined use of end-point IgM ELISA and virus isolation permitted a specific diagnosis in all cases of yellow fever studied during the epidemic in Burkina Faso, and provided a means of rapid diagnosis using a single serum sample, and should be applied in programs of surveillance and epidemic investigation.
Abstract: Summary The complement-fixation (CF) test and IgM antibody-capture enzymelinked immunosorbent assay (ELISA) were compared for the serological diagnosis of medically important flavivirus infections in Africa. The specificity and kinetics of antibody development were studied using serum specimens from humans during investigation of the 1983 yellow fever epidemic in Burkina Faso, from monkeys and young children in eastern Senegal, and from persons with clinical flavivirus infections. IgM antibodies detected by ELISA showed complete specificity in cases of yellow fever, Zika and Wesselsbron infection, whereas extensive crossreactions were noted by ELISA in dengue infections and by the CF test in the case of all flaviviruses. The combined use of end-point IgM ELISA and virus isolation permitted a specific diagnosis in all cases of yellow fever studied during the epidemic in Burkina Faso. These techniques thus provided a means of rapid diagnosis using a single serum sample, and should be applied in programs of surveillance and epidemic investigation. The persistence of IgM antibodies to yellow fever and Zika is relatively brief (1–3 months). Tests on a small number of cases of dengue 2 and 4 also indicated the brief duration of specific IgM compared to CF antibodies. The IgM ELISA has also been applied to the surveillance of sylvatic flavivirus transmission in eastern Senegal. With the successive isolation of yellow fever and Zika viruses in two years, the sensitivity and limits of the serological technique have been elucidated. The best approach for detection of flavivirus transmission is timely serological surveillance of young children; a minimum of one survey should be conducted at the end of the rainy season. Moreover, routine surveillance of wild monkeys for specific IgM antibodies allows early detection of flavivirus activity. This approach is especially useful for the planning and initiation of field studies to assess the occurrence of clinical infections, particularly those due to dengue virus. Two techniques for measurement of IgM antibodies by ELISA were compared. The indirect assay using peroxidase appears to be the most sensitive.

Journal ArticleDOI
TL;DR: No virus budding from the cell surface of the chikungunya- Infected mosquito's salivary glands was found as shown in dengue-infected ones, in contrast to the findings of the mammalian cells infected with chikngunya and/or d Dengue virus(es).
Abstract: Aedes albopictus as well as Aedes aegypti is an important vector of chikungunya and dengue viruses. Electron microscopic observations on the salivary glands of Ae. albopictus infected with chikungunya virus were performed in comparing with those of Ae. aegypti infected with dengue virus. No virus budding from the cell surface of the chikungunya-infected mosquito's salivary glands was found as shown in dengue-infected ones, in contrast to the findings of the mammalian cells such as Vero, KB, IMR, J-111 and BHK-21 cells infected with chikungunya and/or dengue virus(es).

Journal ArticleDOI
TL;DR: Dengue type 3 was the serotype most frequently associated with severe infections and was associated with 27 of the 34 fatal cases in Jakarta, Indonesia.
Abstract: From 1975 to 1983, we clinically studied 1,451 serologically confirmed cases of dengue hemorrhagic fever in Jakarta, Indonesia. Of these cases, 142 were virologically confirmed. Considering these 142 cases, dengue type 3 was the predominant virus type isolated, but all 4 dengue virus serotypes were found. Dengue type 3 was the serotype most frequently associated with severe infections. Whereas 67 (47%) of the 142 patients had a dengue type 3 infection, this serotype was associated with 27 of the 34 fatal cases (79%). Dengue type 3 was found in 42 of the 75 cases with shock (56%), 31 of the 42 cases with encephalopathy (74%), and 19 of the 30 cases with gastrointestinal bleeding (63%).

Patent
23 Oct 1986
TL;DR: In this article, a transformant is screened with the obtained cDNA as a probe to afford a dengue virus 3 type cDNA-containing transformant, which is then cultivated to multiply the cDNA.
Abstract: PURPOSE:To produce a cDNA derived from dengue virus 3 type, by screening a specific transformant to form a transformant containing a dengue virus 3 type cDNA and cultivating the resultant cDNA. CONSTITUTION:Cultivated cells, e.g. cell strain derived from Aedes albopictus Skuse, etc., are infected with dengue virus 3 type and cultivated to multiply the virus, which is then purified RNA is extracted from the purified virus with phenol to give an RNA derived from the virus. The resultant RNA is reacted with dATP, etc., in the presence of a reverse transcriptase to synthesize the corresponding cDNA. RNA is used as a template to prepare a cDNA labeled with a radioisotope and transformants are screened with the obtained cDNA as a probe to afford a dengue virus 3 type cDNA-containing transformant, which is then cultivated to multiply the cDNA. Thereby extraction with phenol, etc., is carried out to provide the aimed cDNA.

Journal Article
TL;DR: This is the first report that cells of mast cell lineage support dengue virus multiplication, and that virus production is enhanced in the presence of anti-dengue antibodies.
Abstract: Dengue type 2 virus (DEN 2) could replicate only to a limited extent in a murine mastocytoma cell line, P815. The viral multiplication was enhanced 10- to 100-fold by mouse anti-DEN 2 antiserum or anti-DEN 2 type-specific monoclonal antibody diluted beyond their neutralizing titers. Cells incubated with virus-antibody mixtures changed morphologically, developing a mature mast cell-like appearance, 4-5 days after infection. The indirect fluorescent antibody technique showed that the enhancement of infection was caused by an increase in the number of DEN 2-infected cells. This is the first report that cells of mast cell lineage support dengue virus multiplication, and that virus production is enhanced in the presence of anti-dengue antibodies.

Journal Article
TL;DR: 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.
Abstract: 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.



Journal Article
TL;DR: I-region gene products were found throughout the dengue virus induced suppressor pathway.
Abstract: We have studied both the cells and the suppressor factors of the dengue virus-induced suppressor pathway for the presence of I-region gene products. The suppressor activity of Ts1, Ts2 and Ts3 cells was abrogated by treatment with anti I-Jk or I-Ak anti-sera and complement. Both the suppressor factors were absorbed out by anti I-Jk and I-Ak immunosorbent columns. The activity of the suppressor factor was abolished by treatment with anti I-Jk antisera. Macrophage presentation of suppressor factor to precursors of Ts2 cells was abolished by treatment with anti I-Ak antisera and complement but not by anti I-Jk antisera. Thus I-region gene products were found throughout the dengue virus induced suppressor pathway.

Journal Article
TL;DR: Treatment of mice with 6-MFA abrogated the DV induced depression of attachment and phagocytosis of opsonized sheep erythrocytes by the peritoneal macrophages, and this effect appears to be mediated by interferon.