(Diagnosis, Diagnostics, Immunodiagnosis, Immunodiagnostics, Pathogenesis, Vaccines & Drugs)


Back To Reference



1622. Bhamarapravati N.  Sutee Y. Live attenuated tetravalent dengue vaccine.  Vaccine.  18 Suppl 2:44-7, 2000 May 26.


The development of a live attenuated tetravalent dengue vaccine is currently the best strategy to obtain a vaccine against dengue viruses. The Mahidol University group developed candidate live attenuated vaccines by attenuation through serial passages in certified primary cell cultures. Dengue serotype 1, 2 and 4 viruses were developed in primary dog kidney cells, whereas dengue serotype 3 was serially passaged in primary African green monkey kidney cells. Tissue culture passaged strain viruses were subjected to biological marker studies. Candidate vaccines have been tested as monovalent (single virus), bivalent (two viruses), trivalent (three viruses) and tetravalent (all four serotype viruses) vaccines in Thai volunteers. They were found to be safe and immunogenic in both adults and children. The Mahidol live attenuated dengue 2 virus was also tested in American volunteers and resulted in good immune response indistinguishable from those induced in Thai volunteers. The master seeds from the four live attenuated virus strains developed were provided to Pasteur Merieux Connaught of France for production on an industrial scale following good manufacturing practice guidelines.


1623. Chaturvedi UC.  Agarwal R.  Elbishbishi EA.  Mustafa AS. Cytokine cascade in dengue hemorrhagic fever: implications for pathogenesis. [Review] [45 refs]  FEMS Immunology & Medical Microbiology.  28(3):183-8, 2000 Jul.


Dengue virus produces a mild acute febrile illness, dengue fever (DF) and a severe illness, dengue hemorrhagic fever (DHF). The characteristic feature of DHF is increased capillary permeability leading to extensive plasma leakage in serous cavities resulting in shock. The pathogenesis of DHF is not fully understood. This paper presents a cascade of cytokines, that in our view, may lead to DHF. The main feature is the early generation of a unique cytokine, human cytotoxic factor (hCF) that initiates a series of events leading to a shift from Th1-type response in mild illness to a Th2-type response resulting in severe DHF. The shift from Th1 to Th2 is regulated by the relative levels of interferon-gamma and interleukin (IL)-10 and between IL-12 and transforming growth factor-beta, which showed an inverse relationship in patients with DF. [References: 45]


1624. Jacobs MG.  Robinson PJ.  Bletchly C.  Mackenzie JM.  Young PR. Dengue virus nonstructural protein 1 is expressed in a glycosyl-phosphatidylinositol-linked form that is capable of signal transduction. FASEB Journal.  14(11):1603-10, 2000 Aug.


Dengue virus nonstructural protein 1 (NS1) is expressed on the surface of infected cells and is a target of human antibody responses to dengue virus infection. We show here that dengue virus uses the cellular glycosyl-phosphatidylinositol (GPI) linkage pathway to express a GPI-anchored form of NS1 and that GPI anchoring imparts a capacity for signal transduction in response to binding of NS1-specific antibody. This study is the first to identify GPI linkage of a virus-encoded protein. The GPI anchor addition signal for NS1 was identified, by transfection of HeLa cells with dengue cDNA constructs, as a downstream hydrophobic domain in NS2A. GPI linkage of NS1 in both transfected and infected cells was demonstrated by cleavage of NS1 from the surface by PI-specific phospholipase C and by metabolic incorporation of the GPI-specific components ethanolamine and inositol. In common with other GPI-anchored proteins, addition of specific antibody resulted in signal transduction, as evidenced by tyrosine phosphorylation of cellular proteins. Antibody-induced signal transduction by GPI-linked NS1 suggests a mechanism of cellular activation that may contribute to the pathogenesis of human dengue disease. Signal transduction by a GPI-anchored viral antigen interacting with a specific antibody that it induces is a new concept in the pathogenesis of viral disease.


1625. King CA.  Marshall JS.  Alshurafa H.  Anderson R.  Release of vasoactive cytokines by antibody-enhanced dengue virus infection of a human mast cell/basophil line. Journal of Virology.  74(15):7146-50, 2000 Aug.


We report here the first demonstration of dengue virus infection and vasoactive cytokine response of a cell of the mast cell/basophil lineage. Infection of KU812 cells was dependent on dengue-specific antibody and gave rise to infectious virions. This antibody-enhanced dengue virus infection triggered a four- to fivefold increase in the release of interleukin-1beta (IL-1beta) and a modest increase for IL-6 but not for an alternate cytokine, granulocyte-macrophage colony-stimulating factor. The results suggest a potential role for mast cells/basophils in the pathogenesis of dengue virus-induced disease.


1626. Lucas GN.  Amerasinghe A.  Sriranganathan S. Dengue haemorrhagic fever in Sri Lanka. Indian Journal of Pediatrics.  67(7):503-4, 2000 Jul.


This is a retrospective study of 354 suspected cases of dengue haemorrhagic fever (DHF), admitted to Lady Ridgeway Hospital (LRH), Colombo during 1996. The objective of the study was to determine the correlation between clinical, laboratory, radiological and serological diagnosis of DHF. Diagnosis was based on the haemagglutination inhibition test. Serologically, 177 cases had dengue infection and, of these, 143 children had DHF. There was only a 50% correlation between clinical suspicion of DHF and positive serology. There was 100% correlation between laboratory and radiological diagnosis of DHF and positive serology.


1627. McBride WJ.  Bielefeldt-Ohmann H. Dengue viral infections; pathogenesis and epidemiology. [Review] [97 refs] Microbes & Infection.  2(9):1041-50, 2000 Jul.


Dengue viral infections affect up to 100 million individuals per year. Dengue haemorrhagic fever is a clinical form of disease characterised by intravascular fluid loss. There has been a marked increase in the incidence of this form of the disease over the last few decades, associated with significant mortality, particularly in the paediatric population. A number of theories relating to the pathogenesis of dengue haemorrhagic fever exist that have evolved from the analysis of the epidemiology of this disease. Virological and immunopathological factors are both important but the exact mechanisms for the disease are unknown.

[References: 97]


1628. Wali JP.  Biswas A.  Aggarwal P.  Wig N.  Handa R. Validity of tourniquet test in dengue haemorrhagic fever. Journal of the Association of Physicians of India.  47(2):203-4, 1999 Feb.


OBJECTIVE: Dengue haemorrhagic fever (DHF), a public problem in most of the tropical countries of South-East Asia, is diagnosed on the basis of demonstrating an increased capillary permeability and thrombocytopenia with concurrent haemoconcentration. Tourniquet test has been recommended as the initial screening procedure of patients with suspected DHF, particularly grade I DHF. The objective of the present study was to study the value of this test as an indicator of haemorrhagic tendencies in patients of DHF. METHODS: One hundred and ten adult patients hospitalized with DHF during outbreak of DHF in 1996 in north India were prospectively studied. The diagnosis of DHF was considered on the basis of haemoconcentration > 20%, evidence of transudation, or presence of shock along with thrombocytopenia. A tourniquet test was conducted in these cases in the standard method. RESULTS: Of the 110 patients of DHF studied, 62 patients (56.4%) had bleeding but tourniquet test was positive in only half of these patients. Forty eight patients (43.6%) did not have any bleeding and the tourniquet test was positive in only 27% cases. CONCLUSIONS: The tourniquet test was positive in only 39.1% of all DHF cases. It is concluded that a negative tourniquet test may not be sufficient to exclude a diagnosis of DHF in a febrile patient. This necessitates the need for the re-defining the clinical criteria for the diagnosis of DHF, particularly grade I DHF.


1629. Wu SJ.  Grouard-Vogel G.  Sun W.  Mascola JR.  Brachtel E.  Putvatana R. Louder MK.  Filgueira L.  Marovich MA.  Wong HK.  Blauvelt A.  Murphy GS.  Robb ML.  Innes BL.  Birx DL.  Hayes CG.  Frankel SS. Human skin Langerhans cells are targets of dengue virus infection [see comments]. Nature Medicine.  6(7):816-20, 2000 Jul.


Dengue virus (DV), an arthropod-borne flavivirus, causes a febrile illness for which there is no antiviral treatment and no vaccine. Macrophages are important in dengue pathogenesis; however, the initial target cell for DV infection remains unknown. As DV is introduced into human skin by mosquitoes of the genus Aedes, we undertook experiments to determine whether human dendritic cells (DCs) were permissive for the growth of DV. Initial experiments demonstrated that blood-derived DCs were 10-fold more permissive for DV infection than were monocytes or macrophages. We confirmed this with human skin DCs (Langerhans cells and dermal/interstitial DCs). Using cadaveric human skin explants, we exposed skin DCs to DV ex vivo. Of the human leukoctye antigen DR-positive DCs that migrated from the skin, emigrants from both dermis and epidermis, 60-80% expressed DV antigens. These observations were supported by histologic findings from the skin rash of a human subject who received an attenuated tetravalent dengue vaccine. Immunohistochemistry of the skin showed CD1a-positive DCs double-labeled with an antibody against DV envelope glycoprotein. These data demonstrate that human skin DCs are permissive for DV infection, and provide a potential mechanism for the transmission of DV into human skin.


1630. Yoshida M.  Igarashi A.  Suwendra P.  Inada K.  Maha MS.  Kari K.  Suda H.  Antonio MT.  Arhana BNP.  Takikawa Y.  Maesawa S.  Yoshida H.  Chiba M. The first report on human cases serologically diagnosed as Japanese encephalitis in Indonesia. Southeast Asian Journal of Tropical Medicine & Public Health.   30(4):698-706, 1999 Dec.


Although Japanese encephalitis (JE) virus was isolated from mosquitos in 1974, human JE cases have never been reported in Indonesia in spite of the prevalence of anti-JE antibodies among human and pig populations as well as abundant JE vector mosquitos. In this report, we describe serological diagnosis of JE cases in Bali. Indonesia. using IgM-capture ELISA both on serum and cerebrospinal fluid (CSF) of the patients. In the first series of our investigation (Series 1), we examined serum specimens from 12 patients with clinical diagnosis of viral encephalitis, meningitis or dengue hemorrhagic fever (DHF), and found 2 possible JE cases. In the next series (Series 2), we examined both serum and CSF from encephalitis patients and gave laboratory diagnosis of JE. One of them was suspected to have concomitant or recent infection with dengue virus, probably type 3. These results strongly indicated that JE has been prevalent in Bali,




2116. No abstract

2117. No abstract

2118. No abstract

2119. No abstract

2120. No abstract


2121. Ho LJ.  Wang JJ.  Shaio MF.  Kao CL.  Chang DM.  Han SW.  Lai JH. Infection of human dendritic cells by dengue virus causes cell maturation and cytokine production. Journal of Immunology.  166(3):1499-506, 2001 Feb 1.


  Dengue virus (DV) infection is a major problem in public health. It can  cause fatal diseases such as Dengue hemorrhagic fever and Dengue shock syndrome. Dendritic cells (DC) are professional APCs required for establishing a primary immune response. Here, we investigated the role of human PBMC-derived DC in DV infection. Using different techniques, including plaque assay, flow cytometry analysis, nested RT-PCR, and confocal microscope and electron microscope examinations, we show that DV can enter cultured human DC and produce virus particles. After entrance, DV could be visualized in cystic vesicles, vacuoles, and the endoplasmic reticulum. The DV-infected DC also showed proliferation and hypertrophy of the endoplasmic reticulum as well as the swollen mitochondria. In addition, the DV-stimulated DC could express maturation markers such as B7-1, B7-2, HLA-DR, CD11b, and CD83. Furthermore, the infection of DC by DV induced production of TNF-alpha and IFN-alpha, but not IL-6 and IL-12. Although DC underwent spontaneous apoptosis in the absence of feeding cytokines, this process appeared to be delayed after DV infection. Our observations provide important information in understanding the pathogenesis of DV infection.


2122. Lin CF.  Lei HY.  Liu CC.  Liu HS.  Yeh TM.  Wang ST.  Yang TI.  Sheu FC. Kuo CF.  Lin YS. Generation of IgM anti-platelet autoantibody in dengue patients. Journal of Medical Virology.  63(2):143-9, 2001 Feb.


  Dengue virus infection causes a wide range of diseases from dengue fever to life-threatening dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS). The mechanisms involved in DHF/DSS pathogenesis remain unclear. Patient sera collected from an outbreak in southern Taiwan from November 1998 to January 1999 were studied. The presence of antibodies which cross-reacted with platelets could be detected in patient sera, and the isotype of these autoantibodies was IgM. The anti-platelet IgM levels were higher in DHF/DSS than in dengue fever patient sera in disease acute phase. These autoantibodies were still detectable in convalescent stage (1-3 weeks after acute phase) and even eight to nine months after illness. The platelet binding activity was not observed in other virus-infected patient sera tested. Further investigation showed that dengue patient sera caused platelet lysis in the presence of complement. The platelet cytotoxicity induced by DHF/DSS patient sera was higher than that by dengue fever sera. Dengue patient sera also inhibited platelet aggregation which, however, appeared to be not related to DHF/DSS development. Copyright 2001 Wiley-Liss, Inc.


2123 No abstract

2124 No abstract


2125. Shurtleff AC.  Beasley DW.  Chen JJ.  Ni H.  Suderman MT.  Wang H.  Xu R. Wang E.  Weaver SC.  Watts DM.  Russell KL.  Barrett AD. Genetic variation in the 3' non-coding region of dengue viruses. Virology.  281(1):75-87, 2001 Mar 1.


  The 3' non-coding region (3'NCR) of strains of dengue 1 (DEN 1), DEN 2, DEN 3, and DEN 4 viruses, isolated in different geographical regions, was sequenced and compared to published sequences of the four dengue viruses. A total of 50 DEN 2 strains was compared: 7 West African strains, 3 Indonesian mosquito strains, 1 Indonesian macaque isolate, and 39 human isolates from Southeast Asia, the South Pacific, and the Caribbean and Americas. Nucleotide sequence alignment revealed few deletions and no repeat sequences in the 3' NCR of DEN 2 viruses and showed that much of the 3' NCR was well conserved. The strains could be divided into two groups, sylvatic and human/mosquito/macaque, based on nucleotide sequence homology. A hypervariable region was identified immediately following the NS5 stop codon, which involved a 2-10 nucleotide deletion in human, mosquito, and macaque isolates compared with the sylvatic strains. The DEN 2 3'NCR was also compared with 3'NCR sequences from strains of DEN 1, DEN 3, and DEN 4 viruses. DEN 1 was found to have four copies of an eight nucleotide imperfect repeat following the NS5 stop codon, while DEN 4 virus had a deletion of 75 nucleotides in the 3'NCR. We propose that the variation in nucleotide sequence in the 3'NCR may have evolved as a function of DEN virus transmission and replication in different mosquito and non-human primate/human host cycles. The results from this study are consistent with the hypothesis that DEN viruses arose from sylvatic progenitors and evolved into human epidemic strains. However, the data do not support the hypothesis that variation in the 3'NCR correlates with DEN virus pathogenesis. Copyright 2001 Academic Press.


2126 No abstract


2127. Sudiro TM.  Zivny J.  Ishiko H.  Green S.  Vaughn DW.  Kalayanarooj S. Nisalak A.  Norman JE.  Ennis FA.  Rothman AL. Analysis of plasma viral RNA levels during acute dengue virus infection using quantitative competitor reverse transcription-polymerase chain reaction. Journal of Medical Virology.  63(1):29-34, 2001 Jan.


  There is increasing recognition of the potential importance of viral burden in the pathogenesis of dengue hemorrhagic fever (DHF). There is little data available, however, describing the kinetics of viral replication in humans with natural dengue virus (DV) infection. Standard procedures for measuring titers of infectious virus in clinical specimens are either laborious or insensitive. We developed a method for measurement of DV RNA in plasma samples based on reverse transcription-polymerase chain reaction (RT-PCR) using a mutant RNA target as a competitor. This technique was reproducible and accurate for samples containing any of the four DV serotypes, and could be applied to samples containing as few as 250 copies of RNA per reaction. We examined plasma viral RNA levels in 80 children with acute DV infection; sequential plasma samples were tested in 34 of these children. Plasma viral RNA levels ranged as high as 10(9) RNA copies/ml, and correlated with titers of infectious virus measured in mosquitoes (r= 0.69). Plasma viral RNA levels fell rapidly during the last several days of the febrile period. We did not find a significant difference in maximal plasma viral RNA levels between children with DHF and children with dengue fever, but peak viral RNA levels were identified in only 16 subjects. We conclude that this quantitative RT-PCR method will be valuable for further studies of natural DV infections.


2128. No abstract



2594. Alvarez M.  Guzman MG.  Pupo M.  Morier L.  Bravo J.  Rodriguez R. Study of biologic attributes of Cuban dengue 2 virus after serial passage in primary dog kidney cells. International Journal of Infectious Diseases.  5(1):35-9, 2001.


  OBJECTIVE: The serial passage of dengue viruses in primary dog kidney (PDK) cells has resulted in selection of attenuated viruses. However, the molecular changes responsible for loss of virulence are not well characterized. This article describes the isolation and biologic attributes of one dengue 2 virulent strain as a first step to allow the study of determinants of virulence at the molecular level. METHODS: A15 dengue 2 Cuban strain was isolated from the viremic plasma of a patient with uncomplicated dengue fever during the 1981 epidemic. This was then subjected to serial passage in PDK cells. Viruses resulting from several PDK passages were compared to the parent strain for plaque size and temperature sensitivity, neurovirulence in newborn mice, and cytopathogenic effects on LLC-MK(2) and C6/36-HT cell lines. RESULTS: A15 dengue 2 Cuban strain was successfully propagated in PDK cells. Primary dog kidney 52 to 53 viruses exhibited several biologic attributes, such as small plaques, temperature sensitivity, reduced mouse neurovirulence, and cytopathic effect in permissive cell lines. CONCLUSIONS: These results represent the first step to allow attenuation of this strain of dengue 2 virus.


2595. Libraty DH.  Pichyangkul S.  Ajariyakhajorn C.  Endy TP.  Ennis FA. Human dendritic cells are activated by dengue virus infection: enhancement by gamma interferon and implications for disease pathogenesis. Journal of Virology.  75(8):3501-8, 2001 Apr.


  The ability of dendritic cells (DCs) to shape the adaptive immune response to viral infection is mediated largely by their maturation and activation state as determined by the surface expression of HLA molecules, costimulatory molecules, and cytokine production. Dengue is an emerging arboviral disease where the severity of illness is influenced by the adaptive immune response to the virus. In this report, we have demonstrated that dengue virus infects and replicates in immature human myeloid DCs. Exposure to live dengue virus led to maturation and activation of both the infected and surrounding, uninfected DCs and stimulated production of tumor necrosis factor alpha (TNF-alpha) and alpha interferon (IFN-alpha). Activation of the dengue virus-infected DCs was blunted compared to the surrounding, uninfected DCs, and dengue virus infection induced low-level release of interleukin-12 p70 (IL-12 p70), a key cytokine in the development of cell-mediated immunity (CMI). Upon the addition of IFN-gamma, there was enhanced activation of dengue virus-infected DCs and enhanced dengue virus-induced IL-12 p70 release. The data suggest a model whereby DCs are the early, primary target of dengue virus in natural infection and the vigor of CMI is modulated by the relative presence or absence of IFN-gamma in the microenvironment surrounding the virus-infected DCs. These findings are relevant to understanding the pathogenesis of dengue hemorrhagic fever and the design of new vaccination and therapeutic strategies.



Back To Reference