Life Sciences Commons^™

Viral Replication And Paracrine Effects Result In Distinct, Functional Responses Of Dendritic Cells Following Infection With Dengue 2 Virus, Zachary Nightingale, Chinmay Patkar, Alan Rothman

Alan Rothman

Dengue virus (DENV), a re-emerging arbovirus, readily infects dendritic cells (DC) in culture and in vivo. However, there have been contradictory reports regarding the effect of DENV infection on DC activation and maturation. DC undergo a series of functional changes following exposure to infectious agents, including cytokine production and costimulatory and MHC molecule induction, culminating in stimulation of adaptive immune responses. Immunological memory to primary DENV infection critically influences disease severity during subsequent infections with heterologous serotypes. To explore these phenomena, we examined DENV infection-dependent and -independent effects on DC secretory, phenotypic, and allostimulatory functions. DENV infection of DC resulted …

Multiple Specificities In The Murine Cd4+ And Cd8+ T-Cell Response To Dengue Virus, Alan Rothman, Ichiro Kurane, Francis Ennis

Alan Rothman

The target epitopes, serotype specificity, and cytolytic function of dengue virus-specific T cells may influence their theoretical roles in protection against secondary infection as well as the immunopathogenesis of dengue hemorrhagic fever. To study these factors in an experimental system, we isolated dengue virus-specific CD4+ and CD8+ T-cell clones from dengue-2 virus-immunized BALB/c mice. The T-cell response to dengue virus in this mouse strain was heterogeneous; we identified at least five different CD4+ phenotypes and six different CD8+ phenotypes. Individual T-cell clones recognized epitopes on the dengue virus pre-M, E, NSl/NS2A, and NS3 proteins and were restricted by the I-Ad, …

Impaired T Cell Proliferation In Acute Dengue Infection, Anuja Mathew, Ichiro Kurane, Sharone Green, David Vaughn, Siripen Kalayanarooj, Saroj Suntayakorn, Francis Ennis, Alan Rothman

Alan Rothman

Decreased proliferative responses to mitogens and recall Ags have been observed in PBMC obtained during several acute human viral infections. To determine whether cell-mediated responses are altered during acute dengue infection, we examined the proliferative responses of PBMC from children enrolled in a prospective study of dengue infections in Thailand. All responses of PBMC during acute illness were compared with the same patients' PBMC obtained at least 6 mo after their infection. Proliferative responses to PHA, anti-CD3, tetanus toxoid, and dengue Ags were decreased significantly in PBMC obtained during the acute infection. The proliferative responses to PHA were restored by …

Intracellular Cytokine Production By Dengue Virus-Specific T Cells Correlates With Subclinical Secondary Infection, Steven Hatch, Timothy Endy, Stephen Thomas, Anuja Mathew, James Potts, Pamela Pazoles, Daniel Libraty, Robert Gibbons, Alan Rothman

Alan Rothman

The pathophysiology of dengue virus infection remains poorly understood, although secondary infection is strongly associated with more severe disease. In the present study, we performed a nested, case-control study comparing the responses of pre-illness peripheral blood mononuclear cells between children who would subsequently develop either subclinical or symptomatic secondary infection 6-11 months after the baseline blood samples were obtained and frozen. We analyzed intracellular cytokine production by CD4(+) and CD8(+) cells in response to stimulation with dengue antigen. We found higher frequencies of dengue virus-specific TNFalpha, IFNgamma-, and IL-2-producing T cells among schoolchildren who subsequently developed subclinical infection, compared with …

Dengue Virus Protein Recognition By Virus-Specific Murine Cd8+ Cytotoxic T Lymphocytes, Alan L. Rothman, Ichiro Kurane, Ching-Juh Lai, Michael Bray, Barry Falgout, Ruhe Men, Francis A. Ennis

Alan Rothman

The identification of the protein targets for dengue virus-specific T lymphocytes may be useful for planning the development of subunit vaccines against dengue. We studied the recognition by murine dengue virus-specific major histocompatibility complex class I-restricted, CD8+ cytotoxic T lymphocytes (CTL) of dengue virus proteins using recombinant vaccinia viruses containing segments of the dengue virus genome. CTL from H-2k mice recognized a single serotype-cross-reactive epitope on the nonstructural (NS) protein NS3. CTL from H-2b mice recognized a serotype-cross-reactive epitope that was localized to NS4a or NS4b. CTL from H-2d mice recognized at least three epitopes: a serotype-specific epitope on one …

Cross-Reactive Memory Cd8(+) T Cells Alter The Immune Response To Heterologous Secondary Dengue Virus Infections In Mice In A Sequence-Specific Manner, Coreen Beaumier, Anuja Mathew, Hema Bashyam, Alan Rothman

Alan Rothman

Dengue virus is the causative agent of dengue fever and the more-severe dengue hemorrhagic fever (DHF). Human studies suggest that the increased risk of DHF during secondary infection is due to immunopathology partially mediated by cross-reactive memory T cells from the primary infection. To model T cell responses to sequential infections, we immunized mice with different sequences of dengue virus serotypes and measured the frequency of peptide-specific T cells after infection. The acute response after heterologous secondary infections was enhanced compared with the acute or memory response after primary infection. Also, the hierarchy of epitope-specific responses was influenced by the …

Dengue: Defining Protective Versus Pathologic Immunity, Alan Rothman

Alan Rothman

Dengue is an expanding public health problem, and an effective vaccine remains elusive. This review discusses how the significant influence of sequential infection with different dengue virus serotypes on the severity of disease can be viewed in terms of beneficial and detrimental effects of heterologous immunity. A more complete understanding of these effects is likely to be critical for predicting optimal vaccine-induced immune responses.

Dengue Virus Nonstructural Protein Ns5 Induces Interleukin-8 Transcription And Secretion, Carey L. Medin, Katherine A. Fitzgerald, Alan L. Rothman

Alan Rothman

Elevated circulating levels of chemokines have been reported in patients with dengue fever and are proposed to contribute to the pathogenesis of dengue disease. To establish in vitro models for chemokine induction by dengue 2 virus (DEN2V), we studied a variety of human cell lines and primary cells. DEN2V infection of HepG2 and primary dendritic cells induced the production of interleukin-8 (IL-8), RANTES, MIP-1alpha, and MIP-1beta, whereas only IL-8 and RANTES were induced following dengue virus infection of HEK293 cells. Chemokine secretion was accompanied by an increase in steady-state mRNA levels. No chemokine induction was observed in HEK293 cells treated …

Determinants Of Inapparent And Symptomatic Dengue Infection In A Prospective Study Of Primary School Children In Kamphaeng Phet, Thailand, Timothy Endy, Kathryn Anderson, Ananda Nisalak, In-Kyu Yoon, Sharone Green, Alan Rothman, Stephen Thomas, Richard Jarman, Daniel Libraty, Robert Gibbons

Alan Rothman

BACKGROUND: Dengue viruses are a major cause of morbidity in tropical and subtropical regions of the world. Inapparent dengue is an important component of the overall burden of dengue infection. It provides a source of infection for mosquito transmission during the course of an epidemic, yet by definition is undetected by health care providers. Previous studies of inapparent or subclinical infection have reported varying ratios of symptomatic to inapparent dengue infection.

METHODOLOGY/PRINCIPAL FINDINGS: In a prospective study of school children in Northern Thailand, we describe the spatial and temporal variation of the symptomatic to inapparent (S:I) dengue illness ratio. Our …

Virus-Induced Decline In Soluble Vascular Endothelial Growth Receptor 2 Is Associated With Plasma Leakage In Dengue Hemorrhagic Fever, Anon Srikiatkhachorn, Chuanpis Ajariyakhajorn, Timothy Endy, Siripen Kalayanarooj, Daniel Libraty, Sharone Green, Francis Ennis, Alan Rothman

Alan Rothman

Some individuals infected with dengue virus develop dengue hemorrhagic fever (DHF), a viral hemorrhagic disease characterized by a transient period of localized plasma leakage. To determine the importance of vascular endothelial growth factor A (VEGF-A) in this syndrome, we compared plasma levels of VEGF-A and the soluble forms of its receptors in patients with DHF to patients with dengue fever (DF), a milder form of dengue virus infection without plasma leakage. We observed a rise in the plasma levels of free, but not total VEGF-A in DHF patients at the time of plasma leakage. This was associated with a decline …

Cell Type-Specific Mechanisms Of Interleukin-8 Induction By Dengue Virus And Differential Response To Drug Treatment, Carey Medin, Alan Rothman

Alan Rothman

In vitro infection with dengue virus induces interleukin (IL)-8 secretion, which increases endothelial cell permeability; this has been proposed as a mechanism for plasma leakage in dengue hemorrhagic fever. We studied the mechanisms of IL-8 induction, using luciferase reporter constructs, and the effect of pharmacological inhibitors of either IL-8 secretion or nuclear factor- kappa B (NF-kappa B) activation on IL-8 induction by dengue 2 virus (DEN2V) infection. IL-8 induction by DEN2V infection was associated with activation of NF- kappa B and activator protein-1 (AP-1) in HEK293A cells but only with activation of AP-1 in HepG2 cells. Treatment with SB203580, a …

Efficient Dengue Virus (Denv) Infection Of Human Muscle Satellite Cells Upregulates Type I Interferon Response Genes And Differentially Modulates Mhc I Expression On Bystander And Denv-Infected Cells, Rajas Warke, Aniuska Becerra, Agatha Zawadzka, Diane Schmidt, Katherine Martin, Krisanthi Giaya, Jonathan Dinsmore, Marcia Woda, Gregory Hendricks, Tracy Levine, Alan Rothman, Irene Bosch

Alan Rothman

Dengue virus (DENV) is a mosquito-borne flavivirus that causes an acute febrile disease in humans, characterized by musculoskeletal pain, headache, rash and leukopenia. The cause of myalgia during DENV infection is still unknown. To determine whether DENV can infect primary muscle cells, human muscle satellite cells were exposed to DENV in vitro. The results demonstrated for the first time high-efficiency infection and replication of DENV in human primary muscle satellite cells. Changes in global gene expression were also examined in these cells following DENV infection using Affymetrix GeneChip analysis. The differentially regulated genes belonged to two main functional categories: cell …

Altered Cytokine Responses Of Dengue-Specific Cd4+ T Cells To Heterologous Serotypes, Maloy Mangada, Alan Rothman

Alan Rothman

The interplay of different inflammatory cytokines induced during a dengue (DEN) virus infection plays a role in either protection or increased disease severity. We measured the frequencies and characterized the cytokine responses of DEN virus-specific memory CD4+ T cells in PBMC of six volunteers who received experimental live attenuated monovalent DEN vaccines. IFN-gamma and TNF-alpha responses to inactivated DEN Ags were detected in up to 0.54 and 1.17% of total circulating CD4+ T cells, respectively. Ags from the homologous serotype elicited the highest IFN-gamma response. The ratio of TNF-alpha- to IFN-gamma-producing CD4+ T cells was higher after stimulation with Ags …

Analysis Of Murine Cd8(+) T-Cell Clones Specific For The Dengue Virus Ns3 Protein: Flavivirus Cross-Reactivity And Influence Of Infecting Serotype, Anne C. Spaulding, Ichiro Kurane, Francis A. Ennis, Alan L. Rothman

Alan Rothman

Serotype-cross-reactive dengue virus-specific cytotoxic T lymphocytes (CTL) induced during a primary dengue virus infection are thought to play a role in the immunopathogenesis of dengue hemorrhagic fever (DHF) during a secondary dengue virus infection. Although there is no animal model of DHF, we previously reported that murine dengue virus-specific CTL responses are qualitatively similar to human dengue virus-specific CTL responses. We used BALB/c mice to study the specificity of the CTL response to an immunodominant epitope on the dengue virus NS3 protein. We mapped the minimal H-2Kd-restricted CTL epitope to residues 298 to 306 of the dengue type 2 virus …

Dengue Virus Induces Novel Changes In Gene Expression Of Human Umbilical Vein Endothelial Cells, Rajas Warke, Kris Xhaja, Katherine Martin, Marcia Fournier, Sunil Shaw, Nathaly Brizuela, Norma De Bosch, David Lapointe, Francis Ennis, Alan Rothman, Irene Bosch

Alan Rothman

Endothelial cells are permissive to dengue virus (DV) infection in vitro, although their importance as targets of DV infection in vivo remains a subject of debate. To analyze the virus-host interaction, we studied the effect of DV infection on gene expression in human umbilical vein endothelial cells (HUVECs) by using differential display reverse transcription-PCR (DD-RTPCR), quantitative RT-PCR, and Affymetrix oligonucleotide microarrays. DD identified eight differentially expressed cDNAs, including inhibitor of apoptosis-1, 2'-5' oligoadenylate synthetase (OAS), a 2'-5' OAS-like (OASL) gene, galectin-9, myxovirus protein A (MxA), regulator of G-protein signaling, endothelial and smooth muscle cell-derived neuropilin-like protein, and phospholipid scramblase 1. …

Dengue Virus Infection And Virus-Specific Hla-A2 Restricted Immune Responses In Humanized Nod-Scid Il2rgammanull Mice, Smita Jaiswal, Todd Pearson, Heather Friberg, Leonard D. Shultz, Dale L. Greiner, Alan L. Rothman, Anuja Mathew

Alan Rothman

BACKGROUND: The lack of a suitable animal model to study viral and immunological mechanisms of human dengue disease has been a deterrent to dengue research.

METHODOLOGY/PRINCIPAL FINDINGS: We sought to establish an animal model for dengue virus (DENV) infection and immunity using non-obese diabetic/severe combined immunodeficiency interleukin-2 receptor gamma-chain knockout (NOD-scid IL2rgamma(null)) mice engrafted with human hematopoietic stem cells. Human CD45(+) cells in the bone marrow of engrafted mice were susceptible to in vitro infection using low passage clinical and established strains of DENV. Engrafted mice were infected with DENV type 2 by different routes and at multiple time points …

Partial Agonist Effect Influences The Ctl Response To A Heterologous Dengue Virus Serotype, Jaroslav Zivny, Matthew Defronzo, William Jarry, Julie Jameson, John Cruz, Francis Ennis, Alan Rothman

Alan Rothman

Activation of dengue serotype-cross-reactive memory CTL during secondary dengue virus (DV) infection is thought to be important in the pathogenesis of dengue hemorrhagic fever. To model this effect, we studied the CTL responses to DV types 2 (D2V) and 3 (D3V) in PBMC from an individual previously infected with D3V. DV-specific CD8+ CTL from this donor recognized two HLA-B62-restricted epitopes on the NS3 protein, aa 71-79 (SVKKDLISY) and 235-243 (AMKGLPIRY). Both D3V-specific and D2V/D3V-cross-reactive CTL clones were detected for each epitope; all D2V-reactive CTL clones could lyse D2V-infected autologous cells. CTL responses to both epitopes were detected in bulk cultures …

Bystander Target Cell Lysis And Cytokine Production By Dengue Virus-Specific Human Cd4(+) Cytotoxic T-Lymphocyte Clones, Susan Gagnon, Francis Ennis, Alan Rothman

Alan Rothman

Dengue hemorrhagic fever, the severe form of dengue virus infection, is believed to be an immunopathological response to a secondary infection with a heterologous serotype of dengue virus. Dengue virus capsid protein-specific CD4(+) cytotoxic T-lymphocyte (CTL) clones were shown to be capable of mediating bystander lysis of non-antigen-presenting target cells. After activation by anti-CD3 or in the presence of unlabeled antigen-presenting target cells, these clones could lyse both Jurkat cells and HepG2 cells as bystander targets. Lysis of HepG2 cells suggests a potential role for CD4(+) CTL in the liver involvement observed during dengue virus infection. Three CD4(+) CTL clones …

Increased Production Of Interleukin-8 In Primary Human Monocytes And In Human Epithelial And Endothelial Cell Lines After Dengue Virus Challenge, Irene Bosch, Kris Xhaja, Luis Estevez, Gregory Raines, Heather Melichar, Rajas Warke, Marcia Fournier, Francis Ennis, Alan Rothman

Alan Rothman

The more severe form of dengue virus infection, dengue hemorrhagic fever, is characterized by plasma leakage and derangements in hemostasis. As elevated interleukin-8 (IL-8) levels have been observed in sera from patients with more severe disease manifestations, a study was initiated to look at the effect of dengue virus infection in vitro on proinflammatory cytokine secretion and expression. A significant increase in IL-8 levels in the culture supernatant of primary human monocytes infected with dengue 2 virus (D2V) New Guinea C (NGC) was found by enzyme-linked immunosorbent assay. Additionally, by reverse transcriptase PCR, the mRNA was also augmented. Among the …

Predominance Of Hla-Restricted Cytotoxic T-Lymphocyte Responses To Serotype-Cross-Reactive Epitopes On Nonstructural Proteins Following Natural Secondary Dengue Virus Infection, Anuja Mathew, Ichiro Kurane, Sharone Green, Henry Stephens, David Vaughn, Siripen Kalayanarooj, Saroj Suntayakorn, Dasnayanee Chandanayingyong, Francis Ennis, Alan Rothman

Alan Rothman

We examined the memory cytotoxic T-lymphocytic (CTL) responses of peripheral blood mononuclear cells (PBMC) obtained from patients in Thailand 12 months after natural symptomatic secondary dengue virus infection. In all four patients analyzed, CTLs were detected in bulk culture PBMC against nonstructural dengue virus proteins. Numerous CD4+ and CD8+ CTL lines were generated from the bulk cultures of two patients, KPP94-037 and KPP94-024, which were specific for NS1.2a (NS1 and NS2a collectively) and NS3 proteins, respectively. All CTL lines derived from both patients were cross-reactive with other serotypes of dengue virus. The CD8+ NS1.2a-specific lines from patient KPP94-037 were HLA …

Dominant Recognition By Human Cd8+ Cytotoxic T Lymphocytes Of Dengue Virus Nonstructural Proteins Ns3 And Ns1.2a, Anuja Mathew, Ichiro Kurane, Alan Rothman, Lingling Zeng, Margo Brinton, Francis Ennis

Alan Rothman

A severe complication of dengue virus infection, dengue hemorrhagic fever (DHF), is hypothesized to be immunologically mediated and virus-specific cytotoxic T lymphocytes (CTLs) may trigger DHF. It is also likely that dengue virus-specific CTLs are important for recovery from dengue virus infections. There is little available information on the human CD8+ T cell responses to dengue viruses. Memory CD8+CTL responses were analyzed to determine the diversity of the T cell response to dengue virus and to identify immunodominant proteins using PBMC from eight healthy adult volunteers who had received monovalent, live-attenuated candidate vaccines of the four dengue serotypes. All the …

B-Cell Responses During Primary And Secondary Dengue Virus Infections In Humans, Anuja Mathew, Kim West, Siripen Kalayanarooj, Robert Gibbons, Anon Srikiatkhachorn, Sharone Green, Daniel Libraty, Smita Jaiswal, Alan Rothman

Alan Rothman

Low-avidity serotype-cross-reactive antibodies are hypothesized to play a key role in triggering severe disease in patients with secondary dengue virus (DENV) infection. However, there is little systematic information about the frequency, avidity, and cross-reactivity of DENV-specific B cells in individuals experiencing primary instead of secondary infection. We compared DENV-specific B-cell responses in a cohort of Thai children with primary or secondary DENV infection. B cells specific for DENV precursor membrane protein, envelope (E) protein, and nonstructural protein 1 were detectable in immune peripheral blood mononuclear cells with the highest frequencies of DENV E-specific B cells detected in patients experiencing primary …

Dengue Virus-Reactive Cd8+ T Cells Display Quantitative And Qualitative Differences In Their Response To Variant Epitopes Of Heterologous Viral Serotypes, Hema Bashyam, Sharone Green, Alan Rothman

Alan Rothman

Reactivation of serotype cross-reactive CD8+ memory T lymphocytes is thought to contribute to the immunopathogenesis of dengue disease during secondary infection by a heterologous serotype. Using cytokine flow cytometry, we have defined four novel HLA-A*02-restricted dengue viral epitopes recognized by up to 1.5% of circulating CD8+ T cells in four donors after primary vaccination. All four donors had the highest cytokine response to the epitope NS4b 2353. We also studied the effect of sequence differences in heterologous dengue serotypes on dengue-reactive CD8+ memory T cell cytokine and proliferative responses. The D3 variant of a different NS4b epitope 2423 and the …

Trail Is A Novel Antiviral Protein Against Dengue Virus, Rajas Warke, Katherine Martin, Krisanthi Giaya, Sunil Shaw, Alan Rothman, Irene Bosch

Alan Rothman

Dengue fever is an important tropical illness for which there is currently no virus-specific treatment. To shed light on mechanisms involved in the cellular response to dengue virus (DV), we assessed gene expression changes, using Affymetrix GeneChips (HG-U133A), of infected primary human cells and identified changes common to all cells. The common response genes included a set of 23 genes significantly induced upon DV infection of human umbilical vein endothelial cells (HUVECs), dendritic cells (DCs), monocytes, and B cells (analysis of variance, P < 0.05). Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), one of the common response genes, was identified as a …

Dengue Virus-Specific Murine T-Lymphocyte Proliferation: Serotype Specificity And Response To Recombinant Viral Proteins, Alan L. Rothman, Ichiro Kurane, Yi-Ming Zhang, Ching-Juh Lai, Francis A. Ennis

Alan Rothman

Definition of the T-lymphocyte responses to dengue viruses should aid in the development of safe and effective vaccines and help to explain the pathophysiology of dengue hemorrhagic fever and dengue shock syndrome. In this study, we demonstrated that dengue virus-specific T lymphocytes were detected in spleen cells from dengue virus-immune mice using an in vitro proliferation assay. Following immunization with a single dose of infectious dengue virus, murine lymphocytes showed increased proliferation when incubated in the presence of viral antigens of the same serotype but not in the presence of control antigens. Depletion experiments with antibody and complement showed that …

Dengue Virus-Specific Human Cd4+ T-Lymphocyte Responses In A Recipient Of An Experimental Live-Attenuated Dengue Virus Type 1 Vaccine: Bulk Culture Proliferation, Clonal Analysis, And Precursor Frequency Determination, Sharone Green, Ichiro Kurane, Robert Edelman, Carol 0. Tacket, Kenneth H. Eckels, David W. Vaughn, Charles H. Hoke, Francis A. Ennis

Sharone Green

We analyzed the CD4+ T-lymphocyte responses to dengue, West Nile, and yellow fever viruses 4 months after immunization of a volunteer with an experimental live-attenuated dengue virus type 1 vaccine (DEN-1 45AZ5). We examined bulk culture proliferation to noninfectious antigens, determined the precursor frequency of specific CD4+ T cells by limiting dilution, and established and analyzed CD4+ T-cell clones. Bulk culture proliferation was predominantly dengue virus type 1 specific with a lesser degree of cross-reactive responses to other dengue virus serotypes, West Nile virus, and yellow fever virus. Precursor frequency determination by limiting dilution in the presence of noninfectious dengue …

Impaired T Cell Proliferation In Acute Dengue Infection, Anuja Mathew, Ichiro Kurane, Sharone Green, David Vaughn, Siripen Kalayanarooj, Saroj Suntayakorn, Francis Ennis, Alan Rothman

Sharone Green

Decreased proliferative responses to mitogens and recall Ags have been observed in PBMC obtained during several acute human viral infections. To determine whether cell-mediated responses are altered during acute dengue infection, we examined the proliferative responses of PBMC from children enrolled in a prospective study of dengue infections in Thailand. All responses of PBMC during acute illness were compared with the same patients' PBMC obtained at least 6 mo after their infection. Proliferative responses to PHA, anti-CD3, tetanus toxoid, and dengue Ags were decreased significantly in PBMC obtained during the acute infection. The proliferative responses to PHA were restored by …

Predominance Of Hla-Restricted Cytotoxic T-Lymphocyte Responses To Serotype-Cross-Reactive Epitopes On Nonstructural Proteins Following Natural Secondary Dengue Virus Infection, Anuja Mathew, Ichiro Kurane, Sharone Green, Henry Stephens, David Vaughn, Siripen Kalayanarooj, Saroj Suntayakorn, Dasnayanee Chandanayingyong, Francis Ennis, Alan Rothman

Sharone Green

We examined the memory cytotoxic T-lymphocytic (CTL) responses of peripheral blood mononuclear cells (PBMC) obtained from patients in Thailand 12 months after natural symptomatic secondary dengue virus infection. In all four patients analyzed, CTLs were detected in bulk culture PBMC against nonstructural dengue virus proteins. Numerous CD4+ and CD8+ CTL lines were generated from the bulk cultures of two patients, KPP94-037 and KPP94-024, which were specific for NS1.2a (NS1 and NS2a collectively) and NS3 proteins, respectively. All CTL lines derived from both patients were cross-reactive with other serotypes of dengue virus. The CD8+ NS1.2a-specific lines from patient KPP94-037 were HLA …

Determinants Of Inapparent And Symptomatic Dengue Infection In A Prospective Study Of Primary School Children In Kamphaeng Phet, Thailand, Timothy P. Endy, Kathryn B. Anderson, Ananda Nisalak, In-Kyu Yoon, Sharone Green, Alan L. Rothman, Stephen J. Thomas, Richard G. Jarman, Daniel H. Libraty, Robert V. Gibbons

Sharone Green

BACKGROUND: Dengue viruses are a major cause of morbidity in tropical and subtropical regions of the world. Inapparent dengue is an important component of the overall burden of dengue infection. It provides a source of infection for mosquito transmission during the course of an epidemic, yet by definition is undetected by health care providers. Previous studies of inapparent or subclinical infection have reported varying ratios of symptomatic to inapparent dengue infection. METHODOLOGY/PRINCIPAL FINDINGS: In a prospective study of school children in Northern Thailand, we describe the spatial and temporal variation of the symptomatic to inapparent (S:I) dengue illness ratio. Our …

B-Cell Responses During Primary And Secondary Dengue Virus Infections In Humans, Anuja Mathew, Kim West, Siripen Kalayanarooj, Robert Gibbons, Anon Srikiatkhachorn, Sharone Green, Daniel Libraty, Smita Jaiswal, Alan Rothman

Sharone Green

Low-avidity serotype-cross-reactive antibodies are hypothesized to play a key role in triggering severe disease in patients with secondary dengue virus (DENV) infection. However, there is little systematic information about the frequency, avidity, and cross-reactivity of DENV-specific B cells in individuals experiencing primary instead of secondary infection. We compared DENV-specific B-cell responses in a cohort of Thai children with primary or secondary DENV infection. B cells specific for DENV precursor membrane protein, envelope (E) protein, and nonstructural protein 1 were detectable in immune peripheral blood mononuclear cells with the highest frequencies of DENV E-specific B cells detected in patients experiencing primary …