Human primary macrophages infected with dengue virus serotype 2, strain 16681, and antibody-dependent enhancement of infection
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ABSTRACT: Human primary monocytes were differentiated for 6days in the presence of M-CSF. The resulting macrophages were infected with dengue virus serotype 2, strain 16681 under the following conditions: Mock, Multiplicity of infection (MOI) 1 without antibodies, MOI 1 with 40ng/mL of irrelevant human antibody, MOI 1 with infection enhancing antibody (40ng/mL of a human monoclonal antibody against dengue), and either MOI 5 or MOI 2.5. Total cell RNA was isolated at 2h post infection or 24h post infection.
Project description:MicroRNAs have emerged as relevant players in resistance to infection. We aimed to identify miRNAs involved in natural resistance to dengue infection. Two groups of people living in dengue endemic area were classified as susceptible (SD) or resistant (RD) to dengue virus (DENV) infection according to their anti-DENV antibody status. We hypothesized that anti-DENV seronegative individuals may represent a population resistant to DENV infection. The miRNome from monocytes of 7 individuals of each group was assessed upon mock- or DENV-2 infection.Dysregulated miRNAs were chosen as candidates for functional studies.
Project description:Dengue virus is the most common arbovirus worldwide and represents a significant public health concern. To date, chronic Dengue infections have not been previously reported. While investigating the etiology of central nervous system (CNS) disease in a patient presenting with progressive dementia, we elucidated a chronic dengue infection within the CNS. Comprehensive viral immune responses in both serum and cerebrospinal fluid (CSF) were profiled by a phage-display assay (VirScan). Enrichment of Dengue viral antibodies were detected in the CSF as compared to the serum. No virus was detected in serum or CSF, but post-mortem analysis confirmed Dengue virus in the brain by quantitative polymerase chain reaction (PCR), immunohistochemistry, RNAscope and sequencing. Dengue virus was detectable by PCR and sequencing from brain biopsy tissue collected 33 months ante-mortem, confirming a chronic infection. Comprehensive antibody profiling assays can aid in the diagnosis of encephalitis of unknown etiologies. Our findings suggest that Dengue virus infections may persist in the CNS and should be considered in patients with progressive dementia in endemic regions or with relevant travel history.
Project description:Healthy flavivirus-naive volunteers (n=11) were infected with the live attenuated dengue serotype 2 challenge virus (rDEN2delta30) as the control arm of a dengue vaccine challenge trial. Whole blood RNA was collected in Paxgene tubes for expression profiling prior to infection (day 0), and on days 8, and 28 after rDEN2delta30 infection. Whole blood RNA was depleted of globin-and rRNA transcripts and equal amounts of depleted RNAs were used to generate libraries for SE 100 RNA sequencing per sample on by Illumina. To generate technical replicates, each library was run in different flow cells/lanes and aggregated to an average of approximately 26 million reads total per sample with <1% variation in counts across lanes in a given sample. Comparisons of gene expression in count-normalized samples were focused on analysis of grouping data by timepoint as well as by examining consensus intra-subject timepoint-associated gene expression changes after rDEN2delta30 infection, focusing on pairwise comparisons (Day 8 vs Day 0, Day 28 vs Day 8, and Day 28 vs,. Day 0).
Project description:Whole blood from patients with acute dengue infection (as determined with PCR) were assessed for global transcriptional changes during different stages of the disease with reference to dengue virus IgG status at study inclusion Whole blood collected in PAX-gene tubes and extracted for total RNA
Project description:Dengue virus is an + strand RNA virus. We have carried our infections of human cells with Dengue and analyzed the translation, replication, and localization of the Dengue RNA. This allowed for clear definition of the life cycle of the Dengue virus inside a host cell. We also assessed the host response to Dengue virus, finding that a large fraction of the translational response is due to Interferon function. Translational and transcriptional analysis of the cellular response to Dengue virus infection
Project description:DNA microarrays and specific RT-PCR assays were used to reveal transcriptional patterns in the blood of children presenting with dengue shock syndrome (DSS) and well-matched patients with uncomplicated dengue. The transcriptome of patients with acute uncomplicated dengue was characterized by a metabolically demanding "host defense" profile; transcripts related to oxidative metabolism, interferon signaling, protein ubiquination, apoptosis and cytokines were prominent. In contrast, the transcriptome of DSS patients was surprisingly benign, particularly with regard to transcripts derived from apoptotic and type I interferon pathways. These data highlight significant heterogeneity in the type or timing of host transcriptional immune responses precipitated by DENV infection independent of the duration of illness. In particular, they suggest that if transcriptional events in the blood compartment contribute to capillary leakage leading to hypovolemic shock, they occur before cardiovascular decompensation occurs, a finding that has implications for rational adjuvant therapy in this syndrome. Whole blood transcriptional profiles of children infected with dengue virus with different clinical outcomes were compared. The subjects including 9 acute dengue shock samples, 9 acute uncomplicated dengue samples, 6 autologous follow up dengue samples and 6 autologous follow up uncomplicated dengue patients. Microarray data was normalised using Genespring GX7 software, statistical analysis was performed in Multiexperiment viewer software. Pathway analysis was performed using Ingenuity Pathway analysis online software.
Project description:Our hypothesis is that dengue induces different innate immune responses in patients with mild respective severe dengue. We further hypothesize that severe dengue infection is a consequence of an over reactive inflammatory response which could be inhibited in an early stage by immune suppressants. We hypothesize that the drugs used in this study induce a down regulated inflammatory response; VP-16 by triggering apoptosis and Rosiglitazone by inhibiting NFkB related cytokine production In-vitro dengue infected U937, transcriptional assessment
Project description:Clinical symptoms of dengue virus (DENV) infection, the most prevalent arthropod-borne viral disease, range from classical mild dengue fever to severe, life-threatening dengue shock syndrome. However, most DENV infections cause few or no symptoms. Asymptomatic DENV-infected patients provide a unique opportunity to decipher the host immune responses leading to virus elimination without negative impact on an individual’s health. We used an integrated approach of transcriptional profiling and immunological analysis to compare a Cambodian population of strictly asymptomatic viremic individuals with clinical dengue patients. Whereas inflammatory pathways and innate immune response pathways were similar between asymptomatic individuals and clinical dengue patients, expression of proteins related to antigen presentation and subsequent T and B cell activation pathways were differentially regulated, independent of viral load and previous DENV infection history. Feedback mechanisms controlled the immune response in asymptomatic viremic individuals, as demonstrated by increased activation of T cell apoptosis-related pathways and FcγRIIB signaling associated with decreased anti-DENV specific antibody concentrations. Taken together, our data illustrate that symptom-free DENV infection in children is associated with determined by increased activation of the adaptive immune compartment and proper control mechanisms, leading to elimination of viral infection without excessive immune activation, with implications for novel vaccine development strategies
Project description:Dengue virus (DENV) can hijack non-neutralizing IgG antibodies to facilitate its uptake into target cells expressing Fc gamma receptors (FcgR) - a process known as antibody-dependent enhancement (ADE) of infection. Beyond a requirement for FcgR, host dependency factors for this non-canonical infection route remain unknown. To identify cellular factors exclusively required for ADE, here, we performed CRISPR knockout screens in an in vitro system permissive to infection only in the presence of IgG antibodies. Validating our approach, a top hit was FcgRIIa, which facilitates binding and internalization of IgG-bound DENV but is not required for canonical infection. Additionally, we identified host factors with no previously described role in DENV infection, including TBC1D24 and SV2B, both of which have known functions in regulated secretion. Using genetic knockout and trans-complemented cells, we validated a functional requirement for these host factors in ADE assays performed with monoclonal antibodies and polyclonal sera in multiple cell lines and using all four DENV serotypes. We show that TBC1D24 and SV2B promote binding of IgG-DENV complexes to cells without affecting FcgRIIa expression levels. Thus, we identify cellular factors beyond FcgR that are required for ADE of DENV infection. Our findings represent a first step towards advancing fundamental knowledge behind the biology of ADE that can ultimately be exploited to inform vaccination and therapeutic approaches.