scholarly journals Chimeric flavivirus enables evaluation of antibodies against dengue virus envelope protein in vitro and in vivo

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Takeshi Kurosu ◽  
Keiko Hanabara ◽  
Azusa Asai ◽  
Sabar Pambudi ◽  
Supranee Phanthanawiboon ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Mammalian Cells ◽  
Neutralizing Antibodies ◽  
Evaluation Process ◽  
Denv Infection ◽  
Interferon Α ◽  
Double Knockout ◽  
Virus Envelope

AbstractIn a secondary dengue virus (DENV) infection, the presence of non-neutralizing antibodies (Abs), developed during a previous infection with a different DENV serotype, is thought to worsen clinical outcomes by enhancing viral production. This phenomenon is called antibody-dependent enhancement (ADE) of infection, and it has delayed the development of therapeutic Abs and vaccines against DENV, as they must be evaluated for the potential to induce ADE. Unfortunately, limited replication of DENV clinical isolates in vitro and in experimental animals hinders this evaluation process. We have, therefore, constructed a recombinant chimeric flavivirus (DV2ChimV), which carries premembrane (prM) and envelope (E) genes of type 2 DENV (DENV-2) R05-624 clinical (Thai) isolate in a backbone of Japanese encephalitis virus (Nakayama strain). DENV E-protein is the most important viral target, not only for neutralizing Abs, but also for infection-enhancing Abs. In contrast to DENV-2 R05-624, DV2ChimV replicated efficiently in cultured mammalian cells and was lethal in interferon-α/β–γ-receptor double-knockout mice. With DV2ChimV, we were able to perform neutralization assays, in vitro and in vivo ADE assays, and in vivo protection assays. These results suggest that the chimeric virus is a powerful tool for evaluation of Abs against DENV.

scholarly journals An affinity-matured human monoclonal antibody targeting fusion loop epitope of dengue virus with in vivo therapeutic potency

2020 ◽  
Author(s):  
Tomohiro Kotaki ◽  
Takeshi Kurosu ◽  
Ariadna Grinyo ◽  
Edgar Davidson ◽  
Siti Churrotin ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Neutralizing Antibodies ◽  
Human Monoclonal Antibody ◽  
Variable Region ◽  
Cross Reactivity ◽  
Affinity Maturation ◽  
Interferon Α ◽  
Fusion Loop

AbstractDengue virus (DENV), from the genus flavivirus of the family flaviviridae, causes serious health problems globally. Human monoclonal antibodies (HuMAb) can be used to elucidate the mechanisms of neutralization and antibody-dependent enhancement (ADE) of DENV infections, leading to the development of a vaccine or therapeutic antibodies. Here, we generated eight HuMAb clones from an Indonesian patient infected with DENV. These HuMAbs exhibited the typical characteristics of weak neutralizing antibodies including high cross-reactivity with other flaviviruses and targeting of the fusion loop epitope (FLE). However, one of the HuMAbs, 3G9, exhibited strong neutralization ability (NT50 < 0.1 µg/ml) and possessed a high somatic hyper-mutation rate of the variable region, indicating affinity-maturation. Administration of this antibody significantly improved the survival rate of interferon-α/β/γ receptor knockout C57BL/6 mice after a lethal DENV challenge. Additionally, Fc-modified 3G9 molecules that had lost their in vitro ADE activity showed significantly enhanced therapeutic potency in vivo and competed strongly with an ADE-prone antibody in vitro. Taken together, the affinity-matured FLE-targeting antibody 3G9 exhibits several promising features for therapeutic application including a low NT50 value, potential for pan-flavivirus infection treatment, and suppression of ADE. This study demonstrates the therapeutic potency of affinity-matured FLE-targeting antibodies.

scholarly journals An affinity-matured human monoclonal antibody targeting fusion loop epitope of dengue virus with in vivo therapeutic potency

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomohiro Kotaki ◽  
Takeshi Kurosu ◽  
Ariadna Grinyo-Escuer ◽  
Edgar Davidson ◽  
Siti Churrotin ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Neutralizing Antibodies ◽  
Human Monoclonal Antibody ◽  
Variable Region ◽  
Cross Reactivity ◽  
Affinity Maturation ◽  
Interferon Α ◽  
Fusion Loop

AbstractDengue virus (DENV), from the genus flavivirus of the family flaviviridae, causes serious health problems globally. Human monoclonal antibodies (HuMAb) can be used to elucidate the mechanisms of neutralization and antibody-dependent enhancement (ADE) of DENV infections, leading to the development of a vaccine or therapeutic antibodies. Here, we generated eight HuMAb clones from an Indonesian patient infected with DENV. These HuMAbs exhibited the typical characteristics of weak neutralizing antibodies including high cross-reactivity with other flaviviruses and targeting of the fusion loop epitope (FLE). However, one of the HuMAbs, 3G9, exhibited strong neutralization (NT50 < 0.1 μg/ml) and possessed a high somatic hyper-mutation rate of the variable region, indicating affinity-maturation. Administration of this antibody significantly prolonged the survival of interferon-α/β/γ receptor knockout C57BL/6 mice after a lethal DENV challenge. Additionally, Fc-modified 3G9 that had lost their in vitro ADE activity showed enhanced therapeutic potency in vivo and competed strongly with an ADE-prone antibody in vitro. Taken together, the affinity-matured FLE-targeting antibody 3G9 exhibits promising features for therapeutic application including a low NT50 value, potential for treatment of various kinds of mosquito-borne flavivirus infection, and suppression of ADE. This study demonstrates the therapeutic potency of affinity-matured FLE-targeting antibodies.

scholarly journals Viperin is anti-viral in vitro but is dispensable for restricting dengue virus replication or induction of innate and inflammatory responses in vivo

2021 ◽  
Vol 102 (10) ◽  
Author(s):  
Wisam-Hamzah Al Shujairi ◽  
Luke P. Kris ◽  
Kylie van der Hoek ◽  
Evangeline Cowell ◽  
Gustavo Bracho-Granado ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Denv Infection ◽  
Brain Morphology ◽  
Moderate Increase ◽  
Tnf Α ◽  
Significant Difference

Viperin has antiviral function against many viruses, including dengue virus (DENV), when studied in cells in culture. Here, the antiviral actions of viperin were defined both in vitro and in a mouse in vivo model of DENV infection. Murine embryonic fibroblasts (MEFs) derived from mice lacking viperin (vip−/−) showed enhanced DENV infection, accompanied by increased IFN-β and induction of ISGs; IFIT1 and CXCL-10 but not IRF7, when compared to wild-type (WT) MEFs. In contrast, subcutaneous challenge of immunocompetent WT and vip−/− mice with DENV did not result in enhanced infection. Intracranial infection with DENV resulted in body weight loss and neurological disease with a moderate increase in mortality in vip−/− compared with WT mice, although this was not accompanied by altered brain morphology, immune cell infiltration or DENV RNA level in the brain. Similarly, DENV induction of IFN-β, IFIT1, CXCL-10, IRF7 and TNF-α was not significantly different in WT and vip−/− mouse brain, although there was a modest but significant increase in DENV induction of IL-6 and IfI27la in the absence of viperin. NanoString nCounter analysis confirmed no significant difference in induction of a panel of inflammatory genes in WT compared to vip−/− DENV-infected mouse brains. Further, polyI:C stimulation of bone marrow-derived macrophages (BMDMs) induced TNF-α, IFN-β, IL-6 and Nos-2, but responses were not different in BMDMs generated from WT or vip−/− mice. Thus, while there is significant evidence of anti-DENV actions of viperin in some cell types in vitro, for DENV infection in vivo a lack of viperin does not affect systemic or brain susceptibility to DENV or induction of innate and inflammatory responses.

scholarly journals Epitope Determinants of a Chimpanzee Dengue Virus Type 4 (DENV-4)-Neutralizing Antibody and Protection against DENV-4 Challenge in Mice and Rhesus Monkeys by Passively Transferred Humanized Antibody

2007 ◽  
Vol 81 (23) ◽  
pp. 12766-12774 ◽  
Author(s):  
Ching-Juh Lai ◽  
Ana P. Goncalvez ◽  
Ruhe Men ◽  
Claire Wernly ◽  
Olivia Donau ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Virus Type ◽  
High Titer ◽  
Neutralizing Antibody ◽  
Denv Infection ◽  
Passive Transfer ◽  
Escape Mutant ◽  
Protective Capacity

ABSTRACT The chimpanzee monoclonal antibody (MAb) 5H2 is specific for dengue virus type 4 (DENV-4) and neutralizes the virus at a high titer in vitro. The epitope detected by the antibody was mapped by sequencing neutralization escape variants of the virus. One variant contained a Lys174-Glu substitution and another contained a Pro176-Leu substitution in domain I of the DENV-4 envelope protein (E). These mutations reduced binding affinity for the antibody 18- to >100-fold. Humanized immunoglobulin G (IgG) 5H2, originally produced from an expression vector, has been shown to be a variant containing a nine-amino-acid deletion in the Fc region which completely ablates antibody-dependent enhancement of DENV replication in vitro. The variant MAb, termed IgG 5H2 ΔD, is particularly attractive for exploring its protective capacity in vivo. Passive transfer of IgG 5H2 ΔD at 20 μg/mouse afforded 50% protection of suckling mice against challenge with 25 50% lethal doses of mouse neurovirulent DENV-4 strain H241. Passive transfer of antibody to monkeys was conducted to demonstrate proof of concept for protection against DENV challenge. Monkeys that received 2 mg/kg of body weight of IgG 5H2 ΔD were completely protected against 100 50% monkey infectious doses (MID50) of DENV-4, as indicated by the absence of viremia and seroconversion. A DENV-4 escape mutant that contained a Lys174-Glu substitution identical to that found in vitro was isolated from monkeys challenged with 106 MID50 of DENV-4. This substitution was also present in all naturally occurring isolates belonging to DENV-4 genotype III. These studies have important implications for possible antibody-mediated prevention of DENV infection.

scholarly journals Discovery of Dengue Virus NS4B Inhibitors

2015 ◽  
Vol 89 (16) ◽  
pp. 8233-8244 ◽  
Author(s):  
Qing-Yin Wang ◽  
Hongping Dong ◽  
Bin Zou ◽  
Ratna Karuna ◽  
Kah Fei Wan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dengue Virus ◽  
Transmembrane Protein ◽  
Selective Inhibition ◽  
Denv Infection ◽  
Viral Pathogens ◽  
Replication Complex ◽  
First Time

ABSTRACTThe four serotypes of dengue virus (DENV-1 to -4) represent the most prevalent mosquito-borne viral pathogens in humans. No clinically approved vaccine or antiviral is currently available for DENV. Here we report a spiropyrazolopyridone compound that potently inhibits DENV bothin vitroandin vivo. The inhibitor was identified through screening of a 1.8-million-compound library by using a DENV-2 replicon assay. The compound selectively inhibits DENV-2 and -3 (50% effective concentration [EC50], 10 to 80 nM) but not DENV-1 and -4 (EC50, >20 μM). Resistance analysis showed that a mutation at amino acid 63 of DENV-2 NS4B (a nonenzymatic transmembrane protein and a component of the viral replication complex) could confer resistance to compound inhibition. Genetic studies demonstrate that variations at amino acid 63 of viral NS4B are responsible for the selective inhibition of DENV-2 and -3. Medicinal chemistry improved the physicochemical properties of the initial “hit” (compound 1), leading to compound 14a, which has goodin vivopharmacokinetics. Treatment of DENV-2-infected AG129 mice with compound 14a suppressed viremia, even when the treatment started after viral infection. The results have proven the concept that inhibitors of NS4B could potentially be developed for clinical treatment of DENV infection. Compound 14a represents a potential preclinical candidate for treatment of DENV-2- and -3-infected patients.IMPORTANCEDengue virus (DENV) threatens up to 2.5 billion people and is now spreading in many regions in the world where it was not previously endemic. While there are several promising vaccine candidates in clinical trials, approved vaccines or antivirals are not yet available. Here we describe the identification and characterization of a spiropyrazolopyridone as a novel inhibitor of DENV by targeting the viral NS4B protein. The compound potently inhibits two of the four serotypes of DENV (DENV-2 and -3) bothin vitroandin vivo. Our results validate, for the first time, that NS4B inhibitors could potentially be developed for antiviral therapy for treatment of DENV infection in humans.

scholarly journals Differential replication of dengue virus serotypes 2 and 3 in coinfections of C6/36 cells and Aedes aegypti mosquitoes

2014 ◽  
Vol 8 (07) ◽  
pp. 876-884 ◽  
Author(s):  
Diana Carolina Quintero-Gil ◽  
Marta Ospina ◽  
Jorge Emilio Osorio-Benitez ◽  
Marlen Martinez-Gutierrez
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Cell Viability ◽  
Denv Infection ◽  
Replication Capacity ◽  
Denv Serotypes ◽  
Viral Genomes ◽  
Diphenyltetrazolium Bromide

Introduction: Different dengue virus (DENV) serotypes have been associated with greater epidemic potential. In turn, the increased frequency in cases of severe forms of dengue has been associated with the cocirculation of several serotypes. Because Colombia is a country with an endemic presence of all four DENV serotypes, the aim of this study was to evaluate the in vivo and in vitro replication of the DENV-2 and DENV-3 strains under individual infection and coinfection conditions. Methodology: C6/36HT cells were infected with the two strains individually or simultaneously (coinfection). Replication capacity was evaluated by RT-qPCR, and the effects on cell viability were assessed with an MTT (3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Additionally, Aedes aegypti mosquitoes were artificially fed the two strains of each serotype individually or simultaneously. The viral genomes were quantified by RT-qPCR and the survival of the infected mosquitoes was compared to that of uninfected controls. Results: In single infections, three strains significantly affected C6/36HT cell viability, but no significant differences were found in the replication capacities of the strains of the same serotype. In the in vivo infections, mosquito survival was not affected, and no significant differences in replication between strains of the same serotype were found. Finally, in coinfections, serotype 2 replicated with a thousandfold greater efficiency than serotype 3 did both in vitro and in vivo. Conclusions: Due to the cocirculation of serotypes in endemic regions, further studies of coinfections in a natural environment would further an understanding of the transmission dynamics that affect DENV infection epidemiology.

Immobilization and neutralization of Treponema pallidum attached to cultured mammalian cells

1985 ◽  
Vol 31 (12) ◽  
pp. 1152-1156
Author(s):  
Thomas Fitzgerald
Keyword(s):  
Mammalian Cells ◽  
Neutralizing Antibodies ◽  
Cultured Cells ◽  
Treponema Pallidum ◽  
Immune Serum ◽  
Immune Reactivity ◽  
Complex Environment ◽  
In Vitro Effects

The in vitro effects of antibodies, complement, and (or) macrophages on Treponema pallidum have been previously characterized using relatively simple systems of organisms incubated with the immune components. In vivo, the more complex environment may alter immune reactivity. Experiments were performed to determine whether immobilizing and neutralizing antibodies retained their effectiveness in a more complex environment involving cultured mammalian cells. Two different protocols were used. In protocol A treponemes and normal or immune serum were mixed and added immediately to the cultured cells. In protocol B treponemes were preincubated for 18 h with cultured cells to maximize treponemal attachment; then normal or immune serum was added. With both protocols, attachment of organisms resulted in less effecient immobilization and neutralization. In further experiments, cultured cells were disrupted with Triton X, leaving cytoskeletal remnants on the vessel surface. Identical immobilization and neutralization experiments were performed in the presence of these remnants. In contrast to the findings with viable cultured cells, treponemal attachment to these nonviable remnants did not effect either antibody reaction. Attached organisms were immobilized or neutralized just as efficiently as unattached organisms. Results are discussed in terms of the altered immune reactivity in more complex in vitro environments.

scholarly journals Infectious clone construction of dengue virus type 2, strain Jamaican 1409, and characterization of a conditional E6 mutation

2006 ◽  
Vol 87 (8) ◽  
pp. 2263-2268 ◽  
Author(s):  
Dennis J. Pierro ◽  
Ma Isabel Salazar ◽  
Barry J. Beaty ◽  
Ken E. Olson
Keyword(s):  
Cell Culture ◽  
Dengue Virus ◽  
Virus Type ◽  
Mammalian Cells ◽  
Infectious Clone ◽  
Cell Types ◽  
Dengue Virus Type 2

A full-length infectious cDNA clone (ic) was constructed from the genome of the dengue virus type 2 (DENV-2) Jamaica83 1409 strain, pBAC1409ic, by using a bacterial artifical chromosome plasmid system. Infectious virus was generated and characterized for growth in cell culture and for infection in Aedes aegypti mosquitoes. During construction, an isoleucine to methionine (Ile→Met) change was found at position 6 in the envelope glycoprotein sequence between low- and high-passage DENV-2 1409 strains. In vitro-transcribed genomic RNA of 1409ic with E6-Ile produced infectious virions following electroporation in mosquito cells, but not mammalian cells, while 1409ic RNA with an E6-Met mutation produced virus in both cell types. Moreover, DENV-2 1409 with the E6-Ile residue produced syncytia in C6/36 cell culture, whereas viruses with E6-Met did not. However, in vitro cell culture-derived growth-curve data and in vivo mosquito-infection rates revealed that none of the analysed DENV-2 strains differed from each other.

scholarly journals Aedes aegypti SNAP and a calcium transporter ATPase influence dengue virus dissemination

2020 ◽  
Author(s):  
Alejandro Marin-Lopez ◽  
Junjun Jiang ◽  
Yuchen Wang ◽  
Yongguo Cao ◽  
Tyler MacNeil ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Aedes Aegypti ◽  
Dengue Virus ◽  
Denv Infection ◽  
Infected Mosquito ◽  
Viral Dissemination ◽  
Protein Components ◽  
Calcium Transporter

AbstractDengue virus (DENV) is a flavivirus that causes marked human morbidity and mortality worldwide, being transmitted to humans by Aedes aegypti mosquitoes. Habitat expansion of Aedes, mainly due to climate change and increasing overlap between urban and wild habitats, places nearly half of the world’s population at risk for DENV infection. After a bloodmeal from a DENV-infected host, the virus enters the mosquito midgut. Next, the virus migrates to, and replicates in, other tissues, like salivary glands. Successful viral transmission occurs when the infected mosquito takes another blood meal on a susceptible host and DENV is released from the salivary gland via saliva into the skin. During viral dissemination in the mosquito and transmission to a new mammalian host, DENV interacts with a variety of vector proteins, which are uniquely important during each phase of the viral cycle. Our study focuses on the interaction between DENV particles and protein components in the A. aegypti vector. We performed a mass spectrometry assay where we identified a set of A aegypti salivary gland proteins which potentially interact with the DENV virion. Using dsRNA to silence gene expression, we analyzed the role of these proteins in viral infectivity. Two of these candidates, a synaptosomal-associated protein (AeSNAP) and a calcium transporter ATPase (ATPase) appear to play a role in viral replication both in vitro and in vivo. These findings suggest that AeSNAP plays a protective role during DENV infection of mosquitoes and that ATPase protein is required for DENV during amplification within the vector.ImportanceAedes aegypti mosquitoes are the major vector of different flaviviruses that cause human diseases, including dengue virus. There is a great need for better therapeutics and preventive vaccines against flaviviruses. Flaviviruses create complex virus-host and virus-vector interactions. The interactions between viral particles and protein components in the vector is not completely understood. In this work we characterize how two mosquito proteins, “AeSNAP” and “ATPase”, influence DENV viral dissemination within A. aegypti, using both in vitro and in vivo models. These results elucidate anti-vector measures that may be potentially be used to control dengue virus spread in the mosquito vector.

scholarly journals Delivery of antiviral small interfering RNA with gold nanoparticles inhibits dengue virus infection in vitro

2014 ◽  
Vol 95 (8) ◽  
pp. 1712-1722 ◽  
Author(s):  
Amber M. Paul ◽  
Yongliang Shi ◽  
Dhiraj Acharya ◽  
Jessica R. Douglas ◽  
Amanda Cooley ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Dengue Virus ◽  
Sirna Delivery ◽  
Vero Cells ◽  
Denv Infection ◽  
Small Interfering Rnas ◽  
Virion Release ◽  
Life Threatening

Dengue virus (DENV) infection in humans can cause flu-like illness, life-threatening haemorrhagic fever or even death. There is no specific anti-DENV therapeutic or approved vaccine currently available, partially due to the possibility of antibody-dependent enhancement reaction. Small interfering RNAs (siRNAs) that target specific viral genes are considered a promising therapeutic alternative against DENV infection. However, in vivo, siRNAs are vulnerable to degradation by serum nucleases and rapid renal excretion due to their small size and anionic character. To enhance siRNA delivery and stability, we complexed anti-DENV siRNAs with biocompatible gold nanoparticles (AuNPs) and tested them in vitro. We found that cationic AuNP–siRNA complexes could enter Vero cells and significantly reduce DENV serotype 2 (DENV-2) replication and infectious virion release under both pre- and post-infection conditions. In addition, RNase-treated AuNP–siRNA complexes could still inhibit DENV-2 replication, suggesting that AuNPs maintained siRNA stability. Collectively, these results demonstrated that AuNPs were able to efficiently deliver siRNAs and control infection in vitro, indicating a novel anti-DENV strategy.

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