scholarly journals Cryo-EM structure of an antibody that neutralizes dengue virus type 2 by locking E protein dimers

Science ◽  
2015 ◽  
Vol 349 (6243) ◽  
pp. 88-91 ◽  
Author(s):  
Guntur Fibriansah ◽  
Kristie D. Ibarra ◽  
Thiam-Seng Ng ◽  
Scott A. Smith ◽  
Joanne L. Tan ◽  
...  

There are four closely-related dengue virus (DENV) serotypes. Infection with one serotype generates antibodies that may cross-react and enhance infection with other serotypes in a secondary infection. We demonstrated that DENV serotype 2 (DENV2)–specific human monoclonal antibody (HMAb) 2D22 is therapeutic in a mouse model of antibody-enhanced severe dengue disease. We determined the cryo–electron microscopy (cryo-EM) structures of HMAb 2D22 complexed with two different DENV2 strains. HMAb 2D22 binds across viral envelope (E) proteins in the dimeric structure, which probably blocks the E protein reorganization required for virus fusion. HMAb 2D22 “locks” two-thirds of or all dimers on the virus surface, depending on the strain, but neutralizes these DENV2 strains with equal potency. The epitope defined by HMAb 2D22 is a potential target for vaccines and therapeutics.

2016 ◽  
Vol 90 (10) ◽  
pp. 5090-5097 ◽  
Author(s):  
William B. Messer ◽  
Boyd L. Yount ◽  
Scott R. Royal ◽  
Ruklanthi de Alwis ◽  
Douglas G. Widman ◽  
...  

ABSTRACTThe four dengue virus (DENV) serotypes, DENV1 through 4, are endemic throughout tropical and subtropical regions of the world. While first infection confers long-term protective immunity against viruses of the infecting serotype, a second infection with virus of a different serotype carries a greater risk of severe dengue disease, including dengue hemorrhagic fever and dengue shock syndrome. Recent studies demonstrate that humans exposed to DENV infections develop neutralizing antibodies that bind to quaternary epitopes formed by the viral envelope (E) protein dimers or higher-order assemblies required for the formation of the icosahedral viral envelope. Here we show that the quaternary epitope target of the human DENV3-specific neutralizing monoclonal antibody (MAb) 5J7 can be partially transplanted into a DENV1 strain by changing the core residues of the epitope contained within a single monomeric E molecule. MAb 5J7 neutralized the recombinant DENV1/3 strain in cell culture and was protective in a mouse model of infection with the DENV1/3 strain. However, the 5J7 epitope was only partially recreated by transplantation of the core residues because MAb 5J7 bound and neutralized wild-type (WT) DENV3 better than the DENV1/3 recombinant. Our studies demonstrate that it is possible to transplant a large number of discontinuous residues between DENV serotypes and partially recreate a complex antibody epitope, while retaining virus viability. Further refinement of this approach may lead to new tools for measuring epitope-specific antibody responses and new vaccine platforms.IMPORTANCEDengue virus is the most important mosquito-borne pathogen of humans worldwide, with approximately one-half the world's population living in regions where dengue is endemic. Dengue immunity following infection is robust and thought to be conferred by antibodies raised against the infecting virus. However, the specific viral components that these antibodies recognize and how they neutralize the virus have been incompletely described. Here we map a region on dengue virus serotype 3 recognized by the human neutralizing antibody 5J7 and then test the functional significance of this region by transplanting it into a serotype 1 virus. Our studies demonstrate a region on dengue virus necessary for 5J7 binding and neutralization. Our work also demonstrates the technical feasibility of engineering dengue viruses to display targets of protective antibodies. This technology can be used to develop new dengue vaccines and diagnostic assays.


Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 913
Author(s):  
Aryati Aryati ◽  
Billy J. Wrahatnala ◽  
Benediktus Yohan ◽  
May Fanny ◽  
Faradila K. N. Hakim ◽  
...  

Outbreaks of dengue virus (DENV) in Indonesia have been mainly caused by the DENV serotype-1; -2; or -3. The DENV-4 was the least-reported serotype in Indonesia during the last five decades. We recently conducted a molecular epidemiology study of dengue in the Jember regency, East Java province, Indonesia. Dengue is endemic in the region and outbreaks occur annually. We investigated the clinical characteristics and etiology of dengue-like febrile illness in this regency to understand the disease dynamics. A total of 191 patients with clinical symptoms similar to dengue were recruited during an 11-month study in 2019–2020. Children accounted for the majority of cases and dengue burden was estimated in 41.4% of the cases based on NS1 antigen, viral RNA, and IgG/IgM antibody detection with the majority (73.4%) being primary infections. Secondary infection was significantly associated with a higher risk of severe dengue manifestation. All four DENV serotypes were detected in Jember. Strikingly, we observed the predominance of DENV-4, followed by DENV-3, DENV-1, and DENV-2. Genotype determination using Envelope gene sequence revealed the classification into Genotype I, Cosmopolitan Genotype, Genotype I, and Genotype II for DENV-1, -2, -3, and -4, respectively. The predominance of DENV-4 in Jember may be associated with a new wave of DENV infections and spread in a non-immune population lacking a herd-immunity to this particular serotype.


2007 ◽  
Vol 81 (23) ◽  
pp. 12816-12826 ◽  
Author(s):  
Soila Sukupolvi-Petty ◽  
S. Kyle Austin ◽  
Whitney E. Purtha ◽  
Theodore Oliphant ◽  
Grant E. Nybakken ◽  
...  

ABSTRACT Neutralization of flaviviruses in vivo correlates with the development of an antibody response against the viral envelope (E) protein. Previous studies demonstrated that monoclonal antibodies (MAbs) against an epitope on the lateral ridge of domain III (DIII) of the West Nile virus (WNV) E protein strongly protect against infection in animals. Based on X-ray crystallography and sequence analysis, an analogous type-specific neutralizing epitope for individual serotypes of the related flavivirus dengue virus (DENV) was hypothesized. Using yeast surface display of DIII variants, we defined contact residues of a panel of type-specific, subcomplex-specific, and cross-reactive MAbs that recognize DIII of DENV type 2 (DENV-2) and have different neutralizing potentials. Type-specific MAbs with neutralizing activity against DENV-2 localized to a sequence-unique epitope on the lateral ridge of DIII, centered at the FG loop near residues E383 and P384, analogous in position to that observed with WNV-specific strongly neutralizing MAbs. Subcomplex-specific MAbs that bound some but not all DENV serotypes and neutralized DENV-2 infection recognized an adjacent epitope centered on the connecting A strand of DIII at residues K305, K307, and K310. In contrast, several MAbs that had poor neutralizing activity against DENV-2 and cross-reacted with all DENV serotypes and other flaviviruses recognized an epitope with residues in the AB loop of DIII, a conserved region that is predicted to have limited accessibility on the mature virion. Overall, our experiments define adjacent and structurally distinct epitopes on DIII of DENV-2 which elicit type-specific, subcomplex-specific, and cross-reactive antibodies with different neutralizing potentials.


2016 ◽  
Vol 113 (3) ◽  
pp. 728-733 ◽  
Author(s):  
Leah C. Katzelnick ◽  
Magelda Montoya ◽  
Lionel Gresh ◽  
Angel Balmaseda ◽  
Eva Harris

The four dengue virus serotypes (DENV1–4) are mosquito-borne flaviviruses that infect ∼390 million people annually; up to 100 million infections are symptomatic, and 500,000 cases progress to severe disease. Exposure to a heterologous DENV serotype, the specific infecting DENV strains, and the interval of time between infections, as well as age, ethnicity, genetic polymorphisms, and comorbidities of the host, are all risk factors for severe dengue. In contrast, neutralizing antibodies (NAbs) are thought to provide long-lived protection against symptomatic infection and severe dengue. The objective of dengue vaccines is to provide balanced protection against all DENV serotypes simultaneously. However, the association between homotypic and heterotypic NAb titers and protection against symptomatic infection remains poorly understood. Here, we demonstrate that the titer of preinfection cross-reactive NAbs correlates with reduced likelihood of symptomatic secondary infection in a longitudinal pediatric dengue cohort in Nicaragua. The protective effect of NAb titers on infection outcome remained significant when controlled for age, number of years between infections, and epidemic force, as well as with relaxed or more stringent criteria for defining inapparent DENV infections. Further, individuals with higher NAb titers immediately after primary infection had delayed symptomatic infections compared with those with lower titers. However, overall NAb titers increased modestly in magnitude and remained serotype cross-reactive in the years between infections, possibly due to reexposure. These findings establish that anti-DENV NAb titers correlate with reduced probability of symptomatic DENV infection and provide insights into longitudinal characteristics of antibody-mediated immunity to DENV in an endemic setting.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4021 ◽  
Author(s):  
Subenya Injampa ◽  
Nataya Muenngern ◽  
Chonlatip Pipattanaboon ◽  
Surachet Benjathummarak ◽  
Khwanchit Boonha ◽  
...  

Background Dengue disease is a leading cause of illness and death in the tropics and subtropics. Most severe cases occur among patients secondarily infected with a different dengue virus (DENV) serotype compared with that from the first infection, resulting in antibody-dependent enhancement activity (ADE). Our previous study generated the neutralizing human monoclonal antibody, D23-1B3B9 (B3B9), targeting the first domain II of E protein, which showed strong neutralizing activity (NT) against all four DENV serotypes. However, at sub-neutralizing concentrations, it showed ADE activity in vitro. Methods In this study, we constructed a new expression plasmid using the existing IgG heavy chain plasmid as a template for Fc modification at position N297Q by site-directed mutagenesis. The resulting plasmid was then co-transfected with a light chain plasmid to produce full recombinant IgG (rIgG) in mammalian cells (N297Q-B3B9). This rIgG was characterized for neutralizing and enhancing activity by using different FcγR bearing cells. To produce sufficient quantities of B3B9 rIgG for further characterization, CHO-K1 cells stably secreting N297Q-B3B9 rIgG were then established. Results The generated N297Q-B3B9 rIgG which targets the conserved N-terminal fusion loop of DENV envelope protein showed the same cross-neutralizing activity to all four DENV serotypes as those of wild type rIgG. In both FcγRI- and RII-bearing THP-1 cells and FcγRII-bearing K562 cells, N297Q-B3B9 rIgG lacked ADE activity against all DENV serotypes at sub-neutralizing concentrations. Fortunately, the N297Q-B3B9 rIgG secreted from stable cells showed the same patterns of NT and ADE activities as those of the N297Q-B3B9 rIgG obtained from transient expression against DENV2. Thus, the CHO-K1 stably expressing N297Q-B3B9 HuMAb can be developed as high producer stable cells and used to produce sufficient amounts of antibody for further characterization as a promising dengue therapeutic candidate. Discussion Human monoclonal antibody, targeted to fusion loop of envelope domainII (EDII), was generated and showed cross-neutralizing activity to 4 serotypes of DENV, but did not cause any viral enhancement activity in vitro. This HuMAb could be further developed as therapeutic candidates.


Viruses ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1346
Author(s):  
Madhumati Sevvana ◽  
Thomas F. Rogers ◽  
Andrew S. Miller ◽  
Feng Long ◽  
Thomas Klose ◽  
...  

Zika virus (ZIKV), a mosquito-borne human flavivirus that causes microcephaly and other neurological disorders, has been a recent focus for the development of flavivirus vaccines and therapeutics. We report here a 4.0 Å resolution structure of the mature ZIKV in complex with ADI-30056, a ZIKV-specific human monoclonal antibody (hMAb) isolated from a ZIKV infected donor with a prior dengue virus infection. The structure shows that the hMAb interactions span across the E protein dimers on the virus surface, inhibiting conformational changes required for the formation of infectious fusogenic trimers similar to the hMAb, ZIKV-117. Structure-based functional analysis, and structure and sequence comparisons, identified ZIKV residues essential for neutralization and crucial for the evolution of highly potent E protein crosslinking Abs in ZIKV. Thus, this epitope, ZIKV’s “Achilles heel”, defined by the contacts between ZIKV and ADI-30056, could be a suitable target for the design of therapeutic antibodies.


2011 ◽  
Vol 51 (184) ◽  
Author(s):  
S B Pun

Dengue is an acute infectious disease caused by dengue viruses and transmitted by the Aedes species of mosquito. The rapid global spread of the dengue virus into new areas has begun to attract more research attention. A series of dengue fever outbreaks in several districts of Nepal has been recently observed. The evidence of all four serotypes (DEN – 1 - 4) could be a consequence of a sudden resurgence of a more severe dengue disease in Nepal. Health care providers need to become familiar with the disease to prevent or control the possibility of future outbreaks. The clinical features, diagnosis, treatment, epidemiological patterns and challenges of dengue virus infection in Nepal will be discussed here. Keywords: Dengue, epidemiological patterns, Nepal.


2014 ◽  
Vol 95 (3) ◽  
pp. 591-600 ◽  
Author(s):  
Meng Ling Moi ◽  
Tomohiko Takasaki ◽  
Tsutomu Omatsu ◽  
Shinichiro Nakamura ◽  
Yuko Katakai ◽  
...  

There are four dengue virus (DENV) serotypes. Primary infection with one does not confer protective immunity against the others. We have reported previously that the marmoset (Callithrix jacchus) is a useful primary DENV infection model. It has been reported that secondary DENV infection with a heterotypic serotype induces viraemia kinetics and antibody responses that differ from those in primary infection. Thus, it is important to determine the utility of the marmoset as a model for secondary DENV infection. Marmosets were infected with heterologous DENV by secondary inoculation, and viraemia kinetics and antibody responses were analysed. The marmosets consistently developed high levels of viraemia after the secondary inoculation with heterologous DENV serotypes. IgM responses were lower compared with primary inoculation responses, whilst IgG responses were rapid and high. Neutralizing activities, which possessed serotype cross-reactive activities, were detected as early as 4 days after inoculation. In addition, infectious viraemia titres were higher when assayed with Fcγ receptor-expressing baby hamster kidney (BHK) cells than when assayed with conventional BHK cells, suggesting the presence of infectious virus–antibody immune complexes. After secondary infection with heterotypic DENV, the marmosets demonstrated viraemia kinetics, IgM and IgG responses, and high levels of serotype cross-reactive neutralizing antibody responses, all of which were consistent with secondary DENV infection in humans. The results indicate the marmoset as a useful animal for studying secondary, as well as primary, DENV infection.


2010 ◽  
Vol 84 (11) ◽  
pp. 5730-5740 ◽  
Author(s):  
Maofu Liao ◽  
Claudia Sánchez-San Martín ◽  
Aihua Zheng ◽  
Margaret Kielian

ABSTRACT The flavivirus dengue virus (DV) infects cells through a low-pH-triggered membrane fusion reaction mediated by the viral envelope protein E. E is an elongated transmembrane protein with three domains and is organized as a homodimer on the mature virus particle. During fusion, the E protein homodimer dissociates, inserts the hydrophobic fusion loop into target membranes, and refolds into a trimeric hairpin in which domain III (DIII) packs against the central trimer. It is clear that E refolding drives membrane fusion, but the steps in hairpin formation and their pH requirements are unclear. Here, we have used truncated forms of the DV E protein to reconstitute trimerization in vitro. Protein constructs containing domains I and II (DI/II) were monomeric and interacted with membranes to form core trimers. DI/II-membrane interaction and trimerization occurred efficiently at both neutral and low pH. The DI/II core trimer was relatively unstable and could be stabilized by binding exogenous DIII or by the formation of mixed trimers containing DI/II plus E protein with all three domains. The mixed trimer had unoccupied DIII interaction sites that could specifically bind exogenous DIII at either low or neutral pH. Truncated DV E proteins thus reconstitute hairpin formation and define properties of key domain interactions during DV fusion.


Vaccines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 88 ◽  
Author(s):  
Jisang Park ◽  
Hyun-Young Lee ◽  
Ly Tuan Khai ◽  
Nguyen Thi Thu Thuy ◽  
Le Quynh Mai ◽  
...  

Dengue virus (DENV) comprises four serotypes in the family Flaviviridae and is a causative agent of dengue-related diseases, including dengue fever. Dengue fever is generally a self-limited febrile illness. However, secondary infection of patients with a suboptimal antibody (Ab) response provokes life-threatening severe dengue hemorrhagic fever or dengue shock syndrome. To develop a potent candidate subunit vaccine against DENV infection, we developed the EDII-cEDIII antigen, which contains partial envelope domain II (EDII) including the fusion loop and BC loop epitopes together with consensus envelope domain III (cEDIII) of all four serotypes of DENV. We purified Ab from mice after immunization with EDII-cEDIII or cEDIII and compared their virus neutralization and Ab-dependent enhancement of DENV infection. Anti-EDII-cEDIII Ab showed stronger neutralizing activity and lower Ab-dependent peak enhancement of DENV infection compared with anti-cEDIII Ab. Following injection of Ab-treated DENV into AG129 mice, anti-EDII-cEDIII Ab ameliorated DENV infection in tissues with primary and secondary infection more effectively than anti-cEDIII Ab. In addition, anti-EDII-cEDIII Ab protected against DENV1, 2, and 4 challenge. We conclude that EDII-cEDIII induces neutralizing and protective Abs, and thus, shows promise as a candidate subunit vaccine for DENV infection.


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