ABSTRACT
The human monoclonal antibody (HmAb) C10 potently cross-neutralizes Zika virus (ZIKV) and dengue virus. Analysis of antibody fragment (Fab) C10 interactions with ZIKV and dengue virus serotype 2 (DENV2) particles by cryoelectron microscopy (cryo-EM) and amide hydrogen/deuterium exchange mass spectrometry (HDXMS) shows that Fab C10 binding decreases overall ZIKV particle dynamics, whereas with DENV2, the same Fab causes increased dynamics. Testing of different Fab C10:DENV2 E protein molar ratios revealed that, at higher Fab ratios, especially at saturated concentrations, the Fab enhanced viral dynamics (detected by HDXMS), and observation under cryo-EM showed increased numbers of distorted particles. Our results suggest that Fab C10 stabilizes ZIKV but that with DENV2 particles, high Fab C10 occupancy promotes E protein dimer conformational changes leading to overall increased particle dynamics and distortion of the viral surface. This is the first instance of a broadly neutralizing antibody eliciting virus-specific increases in whole virus particle dynamics.
Subject(s)
Antibodies, Neutralizing , Dengue Virus , Dengue , Viral Envelope Proteins , Zika Virus Infection , Zika Virus , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/metabolism , Antibodies, Viral/immunology , Cross Reactions , Dengue/immunology , Dengue/virology , Dengue Virus/immunology , Dengue Virus/physiology , Humans , Protein Binding , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/immunology , Viral Envelope Proteins/metabolism , Zika Virus/immunology , Zika Virus/physiology , Zika Virus Infection/immunology , Zika Virus Infection/virologyABSTRACT
The human monoclonal antibody C10 exhibits extraordinary cross-reactivity, potently neutralizing Zika virus (ZIKV) and the four serotypes of dengue virus (DENV1-DENV4). Here we describe a comparative structure-function analysis of C10 bound to the envelope (E) protein dimers of the five viruses it neutralizes. We demonstrate that the C10 Fab has high affinity for ZIKV and DENV1 but not for DENV2, DENV3, and DENV4. We further show that the C10 interaction with the latter viruses requires an E protein conformational landscape that limits binding to only one of the three independent epitopes per virion. This limited affinity is nevertheless counterbalanced by the particle's icosahedral organization, which allows two different dimers to be reached by both Fab arms of a C10 immunoglobulin. The epitopes' geometric distribution thus confers C10 its exceptional neutralization breadth. Our results highlight the importance not only of paratope/epitope complementarity but also the topological distribution for epitope-focused vaccine design.
Subject(s)
Antibodies, Neutralizing , Dengue Virus , Dengue , Viral Envelope Proteins , Zika Virus Infection , Zika Virus , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/metabolism , Antibodies, Viral/immunology , Cell Line , Chlorocebus aethiops , Cross Reactions/immunology , Dengue/immunology , Dengue/virology , Dengue Virus/immunology , Dengue Virus/physiology , Drosophila melanogaster , HEK293 Cells , Humans , Protein Binding , Protein Conformation , Vero Cells , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/immunology , Viral Envelope Proteins/metabolism , Zika Virus/immunology , Zika Virus/physiology , Zika Virus Infection/immunology , Zika Virus Infection/virologyABSTRACT
Antibody-dependent enhancement (ADE) is an important safety concern for vaccine development against dengue virus (DENV) and its antigenically related Zika virus (ZIKV) because vaccine may prime deleterious antibodies to enhance natural infections. Cross-reactive antibodies targeting the conserved fusion loop epitope (FLE) are known as the main sources of ADE. We design ZIKV immunogens engineered to change the FLE conformation but preserve neutralizing epitopes. Single vaccination conferred sterilizing immunity against ZIKV without ADE of DENV-serotype 1-4 infections and abrogated maternal-neonatal transmission in mice. Unlike the wild-type-based vaccine inducing predominately cross-reactive ADE-prone antibodies, B cell profiling revealed that the engineered vaccines switched immunodominance to dispersed patterns without DENV enhancement. The crystal structure of the engineered immunogen showed the dimeric conformation of the envelope protein with FLE disruption. We provide vaccine candidates that will prevent both ZIKV infection and infection-/vaccination-induced DENV ADE.
Subject(s)
Antibody-Dependent Enhancement/immunology , Antigens, Viral/immunology , Cross Reactions/immunology , Dengue Vaccines/immunology , Dengue/prevention & control , Zika Virus/immunology , Aedes , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , B-Lymphocytes/immunology , Chlorocebus aethiops , Cricetinae , Dengue Virus/immunology , HEK293 Cells , Humans , Mice , Mice, Inbred BALB C , Mice, Knockout , Receptor, Interferon alpha-beta/genetics , Vaccination , Vero Cells , Zika Virus Infection/immunology , Zika Virus Infection/prevention & controlABSTRACT
Dengue virus (DENV) is a mosquito-borne member of the Flavivirus genus and includes four serotypes (DENV-1, DENV-2, DENV-3, and DENV-4), each of which is capable of causing dengue fever and dengue hemorrhagic fever/dengue shock syndrome. Serious disease can be seen during primary infection but is more frequent following second infection with a serotype different from that of a previous infection. Infection with wild-type DENV induces high-titered neutralizing antibody that can provide long-term immunity to the homotypic virus and can provide short-term immunity (only several months duration) to a heterotypic DENV. The high level of virus replication seen during both secondary infection with a heterotypic virus and during primary DENV infection in late infancy is a direct consequence of antibody-dependent enhancement of replication. This enhanced virus replication is mediated primarily by preexisting, nonneutralizing, or subneutralizing antibodies to the virion surface antigens that enhance access of the virion-antibody complex to FcγR-bearing cells. Vaccines will need to provide long-term protection against each of the four DENV serotypes by inducing neutralizing antibodies, and live, attenuated and various nonliving virus vaccines are in development.
Subject(s)
Dengue Vaccines/immunology , Dengue Virus/immunology , Dengue/immunology , Dengue/prevention & control , Adaptive Immunity , Animals , Antigens, Viral/immunology , HumansABSTRACT
Dengue virus is a major pathogen, and severe infections can lead to life-threatening dengue hemorrhagic fever. Dengue virus exists as four serotypes, and dengue hemorrhagic fever is often associated with secondary heterologous infections. Antibody-dependent enhancement (ADE) may drive higher viral loads in these secondary infections and is purported to result from antibodies that recognize dengue virus but fail to fully neutralize it. Here we characterize two antibodies, 2C8 and 3H5, that bind to the envelope protein. Antibody 3H5 is highly unusual as it not only is potently neutralizing but also promotes little if any ADE, whereas antibody 2C8 has strong capacity to promote ADE. We show that 3H5 shows resilient binding in endosomal pH conditions and neutralizes at low occupancy. Immunocomplexes of 3H5 and dengue virus do not efficiently interact with Fcγ receptors, which we propose is due to the binding mode of 3H5 and constitutes the primary mechanism of how ADE is avoided.
Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antibody-Dependent Enhancement/immunology , Dengue Virus/immunology , HumansABSTRACT
Dengue virus (DENV) is a mosquito-transmitted RNA virus that infects an estimated 390 million humans each year. Here, we review recent advances in our understanding of the biology of DENV and describe knowledge gaps that have impacted the development of effective vaccines and therapeutics.
Subject(s)
Dengue Virus/physiology , Dengue/virology , Animals , Dengue/immunology , Dengue/prevention & control , Dengue/therapy , Dengue Vaccines/immunology , Dengue Virus/immunology , Humans , Immune EvasionABSTRACT
Dengue is the most common vector-borne viral disease, causing nearly 400 million infections yearly. Currently there are no approved therapies. Antibody epitopes that elicit weak humoral responses may not be accessible by conventional B cell panning methods. To demonstrate an alternative strategy to generating a therapeutic antibody, we employed a non-immunodominant, but functionally relevant, epitope in domain III of the E protein, and engineered by structure-guided methods an antibody directed to it. The resulting antibody, Ab513, exhibits high-affinity binding to, and broadly neutralizes, multiple genotypes within all four serotypes. To assess therapeutic relevance of Ab513, activity against important human clinical features of dengue was investigated. Ab513 mitigates thrombocytopenia in a humanized mouse model, resolves vascular leakage, reduces viremia to nearly undetectable levels, and protects mice in a maternal transfer model of lethal antibody-mediated enhancement. The results demonstrate that Ab513 may reduce the public health burden from dengue.
Subject(s)
Antibodies, Neutralizing/administration & dosage , Antibodies, Neutralizing/chemistry , Dengue Virus/physiology , Dengue/therapy , Immunodominant Epitopes/chemistry , Amino Acid Sequence , Animals , Dengue/immunology , Dengue/virology , Dengue Virus/immunology , Disease Models, Animal , Mice , Models, Molecular , Molecular Sequence Data , Phagocytosis , Protein Engineering , Receptors, Fc/immunology , Sequence AlignmentABSTRACT
The Zika virus (ZIKV) epidemic has resulted in congenital abnormalities in fetuses and neonates. Although some cross-reactive dengue virus (DENV)-specific antibodies can enhance ZIKV infection in mice, those recognizing the DENV E-dimer epitope (EDE) can neutralize ZIKV infection in cell culture. We evaluated the therapeutic activity of human monoclonal antibodies to DENV EDE for their ability to control ZIKV infection in the brains, testes, placentas, and fetuses of mice. A single dose of the EDE1-B10 antibody given 3 d after ZIKV infection protected against lethality, reduced ZIKV levels in brains and testes, and preserved sperm counts. In pregnant mice, wild-type or engineered LALA variants of EDE1-B10, which cannot engage Fcg receptors, diminished ZIKV burden in maternal and fetal tissues, and protected against fetal demise. Because neutralizing antibodies to EDE have therapeutic potential against ZIKV, in addition to their established inhibitory effects against DENV, it may be possible to develop therapies that control disease caused by both viruses.
Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Viral/immunology , Dengue Virus/immunology , Epitopes/immunology , Viral Envelope Proteins/immunology , Zika Virus Infection/immunology , Animals , Brain/immunology , Brain/virology , Chlorocebus aethiops , Cross Reactions/immunology , Dengue Virus/classification , Dengue Virus/metabolism , Female , Fetus/immunology , Fetus/virology , Host-Pathogen Interactions/immunology , Humans , Male , Mice , Neutralization Tests , Pregnancy , Protein Multimerization/immunology , Testis/immunology , Testis/virology , Vero Cells , Viral Envelope Proteins/chemistry , Viral Load/immunology , Zika Virus/immunology , Zika Virus/physiology , Zika Virus Infection/virologyABSTRACT
Adaptive immune responses protect against infection with dengue virus (DENV), yet cross-reactivity with distinct serotypes can precipitate life-threatening clinical disease. We found that clonotypes expressing the T cell antigen receptor (TCR) ß-chain variable region 11 (TRBV11-2) were 'preferentially' activated and mobilized within immunodominant human-leukocyte-antigen-(HLA)-A*11:01-restricted CD8+ T cell populations specific for variants of the nonstructural protein epitope NS3133 that characterize the serotypes DENV1, DENV3 and DENV4. In contrast, the NS3133-DENV2-specific repertoire was largely devoid of such TCRs. Structural analysis of a representative TRBV11-2+ TCR demonstrated that cross-serotype reactivity was governed by unique interplay between the variable antigenic determinant and germline-encoded residues in the second ß-chain complementarity-determining region (CDR2ß). Extensive mutagenesis studies of three distinct TRBV11-2+ TCRs further confirmed that antigen recognition was dependent on key contacts between the serotype-defined peptide and discrete residues in the CDR2ß loop. Collectively, these data reveal an innate-like mode of epitope recognition with potential implications for the outcome of sequential exposure to heterologous DENVs.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , Cross Reactions/immunology , Dengue Virus/immunology , Germ-Line Mutation/immunology , Receptors, Antigen, T-Cell, alpha-beta/immunology , Adaptive Immunity/genetics , Adaptive Immunity/immunology , Amino Acid Sequence , CD8-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/virology , Complementarity Determining Regions/genetics , Complementarity Determining Regions/immunology , Dengue/genetics , Dengue/immunology , Dengue/virology , Dengue Virus/classification , Dengue Virus/genetics , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/genetics , Epitopes, T-Lymphocyte/immunology , HLA-A Antigens/chemistry , HLA-A Antigens/genetics , HLA-A Antigens/immunology , Humans , Models, Molecular , Protein Structure, Tertiary , Receptors, Antigen, T-Cell, alpha-beta/chemistry , Receptors, Antigen, T-Cell, alpha-beta/genetics , Serine Endopeptidases/genetics , Serine Endopeptidases/immunology , Serotyping , Surface Plasmon ResonanceABSTRACT
Zika virus (ZIKV) has recently been associated with birth defects and pregnancy loss after maternal infection. Because dengue virus (DENV) and ZIKV co-circulate, understanding the role of antibody-dependent enhancement in the context of pregnancy is critical. Here, we showed that the presence of DENV-specific antibodies in ZIKV-infected pregnant mice significantly increased placental damage, fetal growth restriction, and fetal resorption. This was associated with enhanced viral replication in the placenta that coincided with an increased frequency of infected trophoblasts. ZIKV-infected human placental tissues also showed increased replication in the presence of DENV antibodies, which was reversed by FcγR blocking antibodies. Furthermore, ZIKV-mediated fetal pathogenesis was enhanced in mice in the presence of a DENV-reactive monoclonal antibody, but not in the presence of the LALA variant, indicating a dependence on FcγR engagement. Our data suggest a possible mechanism for the recent increase in severe pregnancy outcomes after ZIKV infection in DENV-endemic areas.
Subject(s)
Dengue Virus/immunology , Immunity/immunology , Zika Virus Infection/immunology , Zika Virus/immunology , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antibody-Dependent Enhancement/immunology , Cell Line, Tumor , Chlorocebus aethiops , Cross Reactions/immunology , Female , Humans , K562 Cells , Mice , Pregnancy , Vero CellsABSTRACT
T cells play important multifaceted roles during dengue infection, and understanding their responses is important for defining correlates of protective immunity and identifying effective vaccine antigens. Using mass cytometry and a highly multiplexed peptide-HLA (human leukocyte antigen) tetramer staining strategy, we probed T cells from dengue patients-a total of 430 dengue and control candidate epitopes-together with key markers of activation, trafficking, and differentiation. During acute disease, dengue-specific CD8+ T cells expressed a distinct profile of activation and trafficking receptors that distinguished them from non-dengue-specific T cells. During convalescence, dengue-specific T cells differentiated into two major cell fates, CD57+ CD127--resembling terminally differentiated senescent memory cells and CD127+ CD57--resembling proliferation-capable memory cells. Validation in an independent cohort showed that these subsets remained at elevated frequencies up to one year after infection. These analyses aid our understanding of the generation of T cell memory in dengue infection or vaccination.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , Dengue Virus/immunology , Dengue/immunology , HLA Antigens/immunology , Adult , B-Lymphocytes/immunology , CD57 Antigens/metabolism , Cell Differentiation/immunology , Cell Proliferation/physiology , Epitopes, T-Lymphocyte/immunology , Female , HLA Antigens/classification , Humans , Immunologic Memory/immunology , Interleukin-7 Receptor alpha Subunit/metabolism , Killer Cells, Natural/immunology , Lymphocyte Activation/immunology , Male , Middle AgedABSTRACT
BACKGROUND: Butantan-Dengue Vaccine (Butantan-DV) is an investigational, single-dose, live, attenuated, tetravalent vaccine against dengue disease, but data on its overall efficacy are needed. METHODS: In an ongoing phase 3, double-blind trial in Brazil, we randomly assigned participants to receive Butantan-DV or placebo, with stratification according to age (2 to 6 years, 7 to 17 years, and 18 to 59 years); 5 years of follow-up is planned. The objectives of the trial were to evaluate overall vaccine efficacy against symptomatic, virologically confirmed dengue of any serotype occurring more than 28 days after vaccination (the primary efficacy end point), regardless of serostatus at baseline, and to describe safety up to day 21 (the primary safety end point). Here, vaccine efficacy was assessed on the basis of 2 years of follow-up for each participant, and safety as solicited vaccine-related adverse events reported up to day 21 after injection. Key secondary objectives were to assess vaccine efficacy among participants according to dengue serostatus at baseline and according to the dengue viral serotype; efficacy according to age was also assessed. RESULTS: Over a 3-year enrollment period, 16,235 participants received either Butantan-DV (10,259 participants) or placebo (5976 participants). The overall 2-year vaccine efficacy was 79.6% (95% confidence interval [CI], 70.0 to 86.3) - 73.6% (95% CI, 57.6 to 83.7) among participants with no evidence of previous dengue exposure and 89.2% (95% CI, 77.6 to 95.6) among those with a history of exposure. Vaccine efficacy was 80.1% (95% CI, 66.0 to 88.4) among participants 2 to 6 years of age, 77.8% (95% CI, 55.6 to 89.6) among those 7 to 17 years of age, and 90.0% (95% CI, 68.2 to 97.5) among those 18 to 59 years of age. Efficacy against DENV-1 was 89.5% (95% CI, 78.7 to 95.0) and against DENV-2 was 69.6% (95% CI, 50.8 to 81.5). DENV-3 and DENV-4 were not detected during the follow-up period. Solicited systemic vaccine- or placebo-related adverse events within 21 days after injection were more common with Butantan-DV than with placebo (58.3% of participants, vs. 45.6%). CONCLUSIONS: A single dose of Butantan-DV prevented symptomatic DENV-1 and DENV-2, regardless of dengue serostatus at baseline, through 2 years of follow-up. (Funded by Instituto Butantan and others; DEN-03-IB ClinicalTrials.gov number, NCT02406729, and WHO ICTRP number, U1111-1168-8679.).
Subject(s)
Dengue Vaccines , Dengue Virus , Dengue , Vaccines, Attenuated , Adult , Child , Child, Preschool , Humans , Antibodies, Viral , Dengue/prevention & control , Dengue Vaccines/adverse effects , Dengue Vaccines/therapeutic use , Dengue Virus/immunology , Double-Blind Method , Vaccination , Vaccines , Vaccines, Attenuated/adverse effects , Vaccines, Attenuated/therapeutic use , Brazil , Vaccine Efficacy , Adolescent , Young Adult , Middle Aged , Follow-Up StudiesABSTRACT
Dengue is a rapidly emerging, mosquito-borne viral infection, with an estimated 400 million infections occurring annually. To gain insight into dengue immunity, we characterized 145 human monoclonal antibodies (mAbs) and identified a previously unknown epitope, the envelope dimer epitope (EDE), that bridges two envelope protein subunits that make up the 90 repeating dimers on the mature virion. The mAbs to EDE were broadly reactive across the dengue serocomplex and fully neutralized virus produced in either insect cells or primary human cells, with 50% neutralization in the low picomolar range. Our results provide a path to a subunit vaccine against dengue virus and have implications for the design and monitoring of future vaccine trials in which the induction of antibody to the EDE should be prioritized.
Subject(s)
Antibodies, Neutralizing/isolation & purification , Dengue Virus/immunology , Dengue/immunology , Viral Envelope Proteins/immunology , Animals , Antibodies, Monoclonal/blood , Antibodies, Monoclonal/isolation & purification , Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/blood , Biological Assay , Cell Line , Dengue/blood , Enzyme-Linked Immunosorbent Assay , Humans , Immunoblotting , Viral Envelope Proteins/metabolismABSTRACT
The incidence of dengue virus disease has increased globally across the past half-century, with highest number of cases ever reported in 2019 and again in 2023. We analyzed climatological, epidemiological, and phylogenomic data to investigate drivers of two decades of dengue in Cambodia, an understudied endemic setting. Using epidemiological models fit to a 19-y dataset, we first demonstrate that climate-driven transmission alone is insufficient to explain three epidemics across the time series. We then use wavelet decomposition to highlight enhanced annual and multiannual synchronicity in dengue cycles between provinces in epidemic years, suggesting a role for climate in homogenizing dynamics across space and time. Assuming reported cases correspond to symptomatic secondary infections, we next use an age-structured catalytic model to estimate a declining force of infection for dengue through time, which elevates the mean age of reported cases in Cambodia. Reported cases in >70-y-old individuals in the 2019 epidemic are best explained when also allowing for waning multitypic immunity and repeat symptomatic infections in older patients. We support this work with phylogenetic analysis of 192 dengue virus (DENV) genomes that we sequenced between 2019 and 2022, which document emergence of DENV-2 Cosmopolitan Genotype-II into Cambodia. This lineage demonstrates phylogenetic homogeneity across wide geographic areas, consistent with invasion behavior and in contrast to high phylogenetic diversity exhibited by endemic DENV-1. Finally, we simulate an age-structured, mechanistic model of dengue dynamics to demonstrate how expansion of an antigenically distinct lineage that evades preexisting multitypic immunity effectively reproduces the older-age infections witnessed in our data.
Subject(s)
Dengue Virus , Dengue , Phylogeny , Cambodia/epidemiology , Dengue/epidemiology , Dengue/virology , Dengue/immunology , Dengue/transmission , Humans , Dengue Virus/genetics , Dengue Virus/immunology , Climate , Incidence , DemographyABSTRACT
The obligate endosymbiont Wolbachia induces pathogen interference in the primary disease vector Aedes aegypti, facilitating the utilization of Wolbachia-based mosquito control for arbovirus prevention, particularly against dengue virus (DENV). However, the mechanisms underlying Wolbachia-mediated virus blockade have not been fully elucidated. Here, we report that Wolbachia activates the host cytoplasmic miRNA biogenesis pathway to suppress DENV infection. Through the suppression of the long noncoding RNA aae-lnc-2268 by Wolbachia wAlbB, aae-miR-34-3p, a miRNA upregulated by the Wolbachia strains wAlbB and wMelPop, promoted the expression of the antiviral effector defensin and cecropin genes through the Toll pathway regulator MyD88. Notably, anti-DENV resistance induced by Wolbachia can be further enhanced, with the potential to achieve complete virus blockade by increasing the expression of aae-miR-34-3p in Ae. aegypti. Furthermore, the downregulation of aae-miR-34-3p compromised Wolbachia-mediated virus blockade. These findings reveal a novel mechanism by which Wolbachia establishes crosstalk between the cytoplasmic miRNA pathway and the Toll pathway via aae-miR-34-3p to strengthen antiviral immune responses against DENV. Our results will aid in the advancement of Wolbachia for arbovirus control by enhancing its virus-blocking efficiency.
Subject(s)
Aedes , Dengue Virus , Dengue , MicroRNAs , Wolbachia , Wolbachia/physiology , Aedes/microbiology , Aedes/virology , Aedes/immunology , Animals , MicroRNAs/genetics , MicroRNAs/metabolism , Dengue Virus/immunology , Dengue/immunology , Dengue/virology , Toll-Like Receptors/metabolism , Toll-Like Receptors/immunology , Mosquito Vectors/virology , Mosquito Vectors/microbiology , Mosquito Vectors/immunology , Signal Transduction , RNA, Long Noncoding/genetics , RNA, Long Noncoding/immunology , Immunity, Innate , SymbiosisABSTRACT
Dengue virus (DENV) is a medically important flavivirus causing an estimated 50-100 million dengue cases annually, some of whom progress to severe disease. DENV non-structural protein 1 (NS1) is secreted from infected cells and has been implicated as a major driver of dengue pathogenesis by inducing endothelial barrier dysfunction. However, less is known about how DENV NS1 interacts with immune cells and what role these interactions play. Here we report that DENV NS1 can trigger activation of inflammasomes, a family of cytosolic innate immune sensors that respond to infectious and noxious stimuli, in mouse and human macrophages. DENV NS1 induces the release of IL-1ß in a caspase-1 dependent manner. Additionally, we find that DENV NS1-induced inflammasome activation is independent of the NLRP3, Pyrin, and AIM2 inflammasome pathways, but requires CD14. Intriguingly, DENV NS1-induced inflammasome activation does not induce pyroptosis and rapid cell death; instead, macrophages maintain cellular viability while releasing IL-1ß. Lastly, we show that caspase-1/11-deficient, but not NLRP3-deficient, mice are more susceptible to lethal DENV infection. Together, these results indicate that the inflammasome pathway acts as a sensor of DENV NS1 and plays a protective role during infection.
Subject(s)
Dengue Virus , Dengue , Inflammasomes , Macrophages , Viral Nonstructural Proteins , Viral Nonstructural Proteins/metabolism , Viral Nonstructural Proteins/immunology , Animals , Inflammasomes/metabolism , Inflammasomes/immunology , Dengue/immunology , Dengue/virology , Dengue/metabolism , Mice , Dengue Virus/immunology , Humans , Macrophages/immunology , Macrophages/metabolism , Macrophages/virology , Interleukin-1beta/metabolism , Interleukin-1beta/immunology , Mice, Inbred C57BL , Mice, Knockout , Caspase 1/metabolismABSTRACT
Anti-Dengue virus (DENV) antibodies can be either protective or pathogenic in humans with prior DENV infection. In a recent issue of Science, Bardina et al. (2017) demonstrated that passive transfer of immune plasma against DENV and West Nile virus (WNV) can enhance Zika virus (ZIKV) infection and pathogenesis in mice.
Subject(s)
Dengue Virus/immunology , Dengue/virology , Animals , Antibodies, Viral/immunology , Humans , Mice , West Nile virus/immunology , Zika Virus InfectionABSTRACT
Antibody-dependent enhancement (ADE) of disease is a general concern for the development of vaccines and antibody therapies because the mechanisms that underlie antibody protection against any virus have a theoretical potential to amplify the infection or trigger harmful immunopathology. This possibility requires careful consideration at this critical point in the pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here we review observations relevant to the risks of ADE of disease, and their potential implications for SARS-CoV-2 infection. At present, there are no known clinical findings, immunological assays or biomarkers that can differentiate any severe viral infection from immune-enhanced disease, whether by measuring antibodies, T cells or intrinsic host responses. In vitro systems and animal models do not predict the risk of ADE of disease, in part because protective and potentially detrimental antibody-mediated mechanisms are the same and designing animal models depends on understanding how antiviral host responses may become harmful in humans. The implications of our lack of knowledge are twofold. First, comprehensive studies are urgently needed to define clinical correlates of protective immunity against SARS-CoV-2. Second, because ADE of disease cannot be reliably predicted after either vaccination or treatment with antibodies-regardless of what virus is the causative agent-it will be essential to depend on careful analysis of safety in humans as immune interventions for COVID-19 move forward.
Subject(s)
Antibodies, Viral/adverse effects , Antibodies, Viral/immunology , Antibody-Dependent Enhancement/immunology , Betacoronavirus/immunology , Betacoronavirus/pathogenicity , Coronavirus Infections/immunology , Coronavirus Infections/virology , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Animals , Antibodies, Neutralizing/adverse effects , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/therapeutic use , COVID-19 , COVID-19 Vaccines , Coronavirus Infections/prevention & control , Dengue Virus/immunology , Disease Models, Animal , HEK293 Cells , Humans , Immunoglobulin Fab Fragments/immunology , Immunoglobulin Fc Fragments/immunology , Immunoglobulin G/immunology , Macaca mulatta , Mice , Middle East Respiratory Syndrome Coronavirus/immunology , Orthomyxoviridae/immunology , Pandemics , Rats , Severe acute respiratory syndrome-related coronavirus/immunology , SARS-CoV-2 , Viral Vaccines/adverse effects , Viral Vaccines/immunologyABSTRACT
The flavivirus genus consists of several major human pathogens including dengue (DENV) and Zika viruses. The flavivirus nonstructural protein 1 (NS1) plays an important role in disease progression, for example, in the development of severe dengue disease. Anti-NS1 antibodies have been shown to confer protection, and two new studies by Biering et al. and Modhiran et al. on the structure of NS1:antibody complexes reveal their mechanism of neutralization.
Subject(s)
Dengue Virus , Dengue , Flavivirus , Zika Virus Infection , Zika Virus , Antibodies, Viral , Dengue Virus/immunology , Humans , Viral Nonstructural ProteinsABSTRACT
Serum-neutralizing antibody titers are a critical measure of vaccine immunogenicity and are used to determine flavivirus seroprevalence in study populations. An effective dengue virus (DENV) vaccine must confer simultaneous protection against viruses grouped within four antigenic serotypes. Existing flavivirus neutralization assays, including the commonly used plaque/focus reduction neutralization titer (PRNT/FRNT) assay, require an individual assay for each virus, serotype, and strain and easily become a labor-intensive and time-consuming effort for large epidemiological studies or vaccine trials. Here, we describe a multiplex reporter virus particle neutralization titer (TetraPlex RVPNT) assay for DENV that allows simultaneous quantitative measures of antibody-mediated neutralization of infection against all four DENV serotypes in a single low-volume clinical sample and analyzed by flow cytometry. Comparative studies confirm that the neutralization titers of antibodies measured by the TetraPlex RVPNT assay are similar to FRNT/PRNT assay approaches performed separately for each viral strain. The use of this high-throughput approach enables the careful serological study in DENV endemic populations and vaccine recipients required to support the development of a safe and effective tetravalent DENV vaccine. IMPORTANCE: As a mediator of protection against dengue disease and a serological indicator of prior infection, the detection and quantification of neutralizing antibodies against DENV is an important "gold standard" tool. However, execution of traditional neutralizing antibody assays is often cumbersome and requires repeated application for each virus or serotype. The optimized RVPNT assay described here is high-throughput, easily multiplexed across multiple serotypes, and targets reporter viral particles that can be robustly produced for all four DENV serotypes. The use of this transformative RVPNT assay will support the expansion of neutralizing antibody datasets to answer research and public health questions often limited by the more cumbersome neutralizing antibody assays and the need for greater quantities of test serum.