DENV Peptides Delivered as Spherical Nucleic Acid Constructs Enhance Antigen Presentation and Immunogenicity in vitro and in vivo.

Background: The global prevalence of Dengue virus (DENV) infection poses a significant health risk, urging the need for effective vaccinations. Peptide vaccines, known for their capacity to induce comprehensive immunity against multiple virus serotypes, offer promise due to their stability, safety, and design flexibility. Spherical nucleic acid (SNA), particularly those with gold nanoparticle cores, present an attractive avenue for enhancing peptide vaccine efficacy due to their modularity and immunomodulatory properties. Methods: The spherical nucleic acid-TBB (SNA-TBB), a novel nanovaccine construct, was fabricated through the co-functionalization process of SNA with epitope peptide, targeting all four serotypes of the DENV. This innovative approach aims to enhance immunogenicity and provide broad-spectrum protection against DENV infections. The physicochemical properties of SNA-TBB were characterized using dynamic light scattering, zeta potential measurement, and transmission electron microscopy. In vitro assessments included endocytosis studies, cytotoxicity evaluation, bone marrow-dendritic cells (BMDCs) maturation and activation analysis, cytokine detection, RNA sequencing, and transcript level analysis in BMDCs. In vivo immunization studies in mice involved evaluating IgG antibody titers, serum protection against DENV infection and safety assessment of nanovaccines. Results: SNA-TBB demonstrated successful synthesis, enhanced endocytosis, and favorable physicochemical properties. In vitro assessments revealed no cytotoxicity and promoted BMDCs maturation. Cytokine analyses exhibited heightened IL-12p70, TNF-α, and IL-1ß levels. Transcriptomic analysis highlighted genes linked to BMDCs maturation and immune responses. In vivo studies immunization with SNA-TBB resulted in elevated antigen-specific IgG antibody levels and conferred protection against DENV infection in neonatal mice. Evaluation of in vivo safety showed no signs of adverse effects in vital organs. Conclusion: The study demonstrates the successful development of SNA-TBB as a promising nanovaccine platform against DENV infection and highlights the potential of SNA-based peptide vaccines as a strategy for developing safe and effective antiviral immunotherapy.

Progress and challenges in development of animal models for dengue virus infection.

ABSTRACTThe severity of the dengue epidemic is on the rise, with its geographic range had expanded to southern Europe by 2024. In this August, the WHO updated the pathogens that could spark the next pandemic, dengue virus was on the list. Vaccines and drugs serve as powerful tools for both preventing dengue infections and treating patients. Animal models play a pivotal role in vaccine development and drug screening. Available potential susceptible animals, including non-human primates, rodents, pigs, and tree shrews, have been extensively explored to establish animal models of dengue disease. Despite significant advancements, there are still notable limitations. Different animal models exhibit distinct constraining factors such as viraemia, host susceptibility, immune function of the host, clinical symptoms, ADE (antibody-dependent enhancement) phenomena, cytokine storm response to various serotypes and strain variations. Furthermore, despite extensive research on the dengue virus receptor in recent years, genetically modified animal models immunocompetent harbouring dengue virus susceptibility receptors have not yet been available. This work reviewed the research progress of dengue virus receptors and dengue animal models, suggesting that the development of genetically modified murine models expressing dengue virus functional receptors may hold a promise for future dengue disease research, especially for its vaccine development.

Pre-vax metabolic clues: Cracking the code to a better dengue vaccine.

Multi-omic analysis deciphers the impact of cell-intrinsic and systemic metabolomes on dengue vaccination immunogenicity.

Role of the dengue vaccine TAK-003 in an outbreak response: Modeling the Sri Lanka experience.

BACKGROUND: Outbreaks of dengue can overburden hospital systems, drastically reducing capacity for other care. The 2017 dengue serotype 2 (DENV-2) outbreak in Sri Lanka coincided with vaccination in an ongoing phase 3 efficacy trial of a tetravalent dengue vaccine, TAK-003 (NCT02747927). Here, we present data on the efficacy of TAK-003 following two doses of the vaccine administered 3 months apart in participants aged 4-16 years in Sri Lanka. In addition, we have used the 2017 outbreak dynamics to model the potential impact of TAK-003 on virologically confirmed dengue (VCD) cases and hospitalizations during an outbreak situation. METHODOLOGY/PRINCIPAL FINDINGS: Modeling was performed using an age-structured, host-vector, spatial and stochastic transmission model, assuming 65% vaccine coverage and 30 days until initiation of vaccination. Efficacy of TAK-003 against VCD and hospitalized VCD cases was based on data against DENV-2 from the first year of the phase 3 trial. Vaccine efficacy and safety findings in Sri Lanka were in line with those of the overall trial population. The efficacy estimates in Sri Lanka up to the first 12 months after the second dose of TAK-003 were 94.7% and 95.7% against VCD and hospitalized VCD cases, respectively. Modeling of the trial data over an extended geographic area showed a substantial reduction in cases and a flattening of outbreak curves from TAK-003 use. The baseline vaccination scenario (initiation at 30 days, 65% target coverage, vaccine effective at 14 days, 70% hospitalization rate, VE of 95% for VCD and 97% for hospitalized VCD, and 47% for asymptomatic) resulted in a 69.1% reduction in VCD cases and 72.7% reduction in VCD hospitalizations compared with no vaccination. An extreme high scenario (vaccination initiated at Day 15, 80% coverage rate, baseline VE) resulted in 80.3% and 82.3% reduction in VCD and VCD hospitalizations, respectively. Vaccine performance, speed of vaccination campaign initiation, and vaccine coverage were key drivers in reducing VCD cases and hospitalizations. CONCLUSIONS/SIGNIFICANCE: Overall, the study and modeling results indicate that TAK-003 has the potential of meaningful utility in dengue outbreaks in endemic areas.

The N and C-terminal deleted variant of the dengue virus NS1 protein is a potential candidate for dengue vaccine development.

NS1 is an elusive dengue protein, involved in viral replication, assembly, pathogenesis, and immune evasion. Its levels in blood plasm are positively related to disease severity like thrombocytopenia, hemorrhage, and vascular leakage. Despite its pathogenic roles, NS1 is being used in various vaccine formulations due to its sequence conservancy, ability to produce protective antibodies and low risk for inducing antibody-dependent enhancement. In this study, we have used bioinformatics tools and reported literature to develop an NS1 variant (dNS1). Molecular docking studies were performed to evaluate the receptor-binding ability of the NS1 and dNS1 with TLR4. NS1 and dNS1 (153 to 312 amino acid region) genes were cloned, expressed and protein was purified followed by refolding. Docking studies showed the binding of NS1 and dNS1 with the TLR4 receptor which suggests that N and C-terminal sequences of NS1 are not critical for receptor binding. Antibodies against NS1 and dNS1 were raised in rabbits and binding affinity of anti-dNS1 anti-NS1 sera was evaluated against both NS1 and dNS1. Similar results were observed through western blotting which highlight that N and C-terminal deletion of NS1 does not compromise the immunogenic potential of dNS1 hence, supports its use in future vaccine formulations as a substitute for NS1.

Effectiveness and safety of the tetravalent TAK-003 dengue vaccine: a systematic review.

In Argentina, the dengue virus has experienced an increase in recent years. This study aims to conduct a systematic review to evaluate the effectiveness and safety of the TAK-003 tetravalent dengue vaccine in this context. A systematic review of randomized controlled trials comparing the effectiveness and safety of the vaccine with placebo in the general population was conducted. The search was carried out in Epistemonikos, and two researchers independently assessed the studies. Risk of bias was evaluated using the Cochrane Rob 2 tool. A meta-analysis of the results was performed, and the certainty of evidence was assessed using the GRADE methodology. We concluded, with high certainty of evidence, that the tetravalent dengue vaccine reduces severe infections (RR 0.17, 95% CI 0.12 to 0.24) and infections by the dengue virus (RR 0.40, 95% CI 0.36 to 0.45) in a population ≤17 years. The vaccine may not increase the risk of serious adverse events, although it is important to note the low certainty of evidence (RR 1.04, 95% CI: 0.69-1.55). The use of the tetravalent dengue vaccine decreases the risk of severe and non-severe dengue infections in this population. However, there is low certainty of evidence regarding the vaccine's safety. The decision to vaccinate should consider the magnitude of benefits relative to the risk of infection.

En Argentina, el virus del dengue ha experimentado un aumento en los últimos años. Este estudio se propone realizar una revisión sistemática para evaluar la efectividad y seguridad de la vacuna TAK-003 tetravalente contra el dengue en este contexto. Se llevó a cabo una revisión sistemática de ensayos clínicos controlados aleatorizados que comparaban la efectividad y seguridad de la vacuna con placebo en la población general. La búsqueda se efectuó en Epistemonikos y dos investigadores evaluaron los estudios de manera independiente. El riesgo de sesgo se evaluó con la herramienta Rob 2 de Cochrane. Se realizó un metaanálisis de los resultados y la certeza en la evidencia se evaluó mediante la metodología GRADE. Concluimos, con alta certeza de evidencia, que la vacuna tetravalente contra el dengue reduce las infecciones graves (RR 0.17, IC 95% 0.12 a 0.24) e infecciones por el virus del dengue (RR 0.40, IC 95% 0.36 a 0.45) en una población de ≤17 años. La vacuna podría no incrementar el riesgo de eventos adversos serios, aunque es importante destacar la baja certeza de evidencia (RR 1.04, IC 95%: 0.69-1.55). La aplicación de la vacuna tetravalente contra el dengue disminuye el riesgo de infecciones graves y no graves por el dengue en esta población. No obstante, existe baja certeza en la evidencia en relación a la seguridad de la vacuna. La decisión de la vacunación debe considerar la magnitud de los beneficios en función del riesgo de infección.

Regional molecular epidemiology of dengue and the potential optimization of its control through the use of vaccines. Report of the Arbovirus Committee of the Latin American Society of Pediatric Infectious Diseases, SLIPE.

INTRODUCTION: Dengue disease represents a large and growing global threat to public health, accounting for a significant burden to health systems of endemic countries. The World Health Organization's (WHO) Strategic Advisory Group of Experts (SAGE) and the European Medicines Agency (EMA) currently recommend the use of TAK-003 dengue vaccine in high dengue burden and transmission settings for countries considering vaccination as part of their integrated management strategy for prevention and control of Dengue. AREAS COVERED: This paper describes the main conclusions of a workshop held by the Arbovirus Committee of the Latin American Society of Pediatric Infectious Diseases (SLIPE) in November 2023, to generate consensus recommendations on the introduction of this new vaccine in the region. Considerations were made regarding the molecular epidemiology of dengue infection in the Americas and the need for more precise phylogenetic classification and correlation with clinical outcome and disease severity. EXPERT OPINION: Introduction of dengue vaccine should be considered as an strategy for health entities in the region, with participation of social sectors, scientific societies, and ministries of health that could be able to create a successful vaccination program.

Expression of dengue capsid-like particles in silkworm and display of envelope domain III of dengue virus serotype 2.

Dengue virus (DENV) is a considerable public health threat affecting millions of people globally. Vaccines for dengue are an important strategy to reduce the disease burden. We expressed capsid (C2) and envelope domain III of dengue virus serotype 2 (2EDIII) separately in the silkworm expression system. We conjugated them employing the monomeric streptavidin (mSA2) and biotin affinity to display the antigenic 2EDIII on the C2-forming capsid-like particle (CLP). Purified 2EDIII-displaying C2 (CLP/2EDIII) was immunogenic in BALB/c mice, eliciting neutralizing antibodies confirmed by a single-round infectious particle (SRIP) neutralization assay. Th1 cytokine levels were upregulated for the CLP/2EDIII group, and the anti-inflammatory IL-10 and pro-inflammatory IL-6 cytokine levels were also raised compared to the 2EDIII and the control groups. Elevated cytokine levels for CLP/2EDIII indicate the importance of displaying the 2EDIII as CLP/2EDIII rather than as an individual subunit. This study is the first to express the C2 protein as self-assembling CLP in vivo and 2EDIII separately in the silkworm expression system and conjugate them to form a monovalent CLP. Thus, this CLP/2EDIII display method may pave the way for an efficient tetravalent dengue vaccine candidate.

Simultaneous quantitation of neutralizing antibodies against all four dengue virus serotypes using optimized reporter virus particles.

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.

Multi-epitope peptide vaccines targeting dengue virus serotype 2 created via immunoinformatic analysis.

The Middle East has witnessed a greater spread of infectious Dengue viruses, with serotype 2 (DENV-2) being the most prevalent form. Through this work, multi-epitope peptide vaccines against DENV-2 that target E and nonstructural (NS1) proteins were generated through an immunoinformatic approach. MHC class I and II and LBL epitopes among NS1 and envelope E proteins sequences were predicted and their antigenicity, toxicity, and allergenicity were investigated. Studies of the population coverage denoted the high prevalence of NS1 and envelope-E epitopes among different countries where DENV-2 endemic. Further, both the CTL and HTL epitopes retrieved from NS1 epitopes exhibited high conservancies' percentages with other DENV serotypes (1, 3, and 4). Three vaccine constructs were created and the expected immune responses for the constructs were estimated using C-IMMSIM and HADDOCK (against TLR 2,3,4,5, and 7). Molecular dynamics simulation for vaccine construct 2 with TLR4 denoted high binding affinity and stability of the construct with the receptor which might foretell favorable in vivo interaction and immune responses.

Immune responses and severe dengue: what have we learned?

PURPOSE OF REVIEW: With the marked rise in dengue globally, developing well tolerated and effective vaccines and therapeutics is becoming more important. Here we discuss the recent developments in the understanding of immune mechanisms that lead to severe dengue and the learnings from the past, that can help us to find therapeutic targets, prognostic markers, and vaccines to prevent development of severe disease. RECENT FINDINGS: The extent and duration of viraemia often appears to be associated with clinical disease severity but with some variability. However, there also appear to be significant differences in the kinetics of viraemia and nonstructural protein 1 (NS1) antigenemia and pathogenicity between different serotypes and genotypes of the DENV. These differences may have significant implications for development of treatments and in inducing robust immunity through dengue vaccines. Although generally higher levels of neutralizing antibodies are thought to protect against infection and severe disease, there have been exceptions and the specificity, breadth and functionality of the antibody responses are likely to be important. SUMMARY: Although there have been many advances in our understanding of dengue pathogenesis, viral and host factors associated with occurrence of severe dengue, vascular leak and the immune correlates of protection remain poorly understood.

A pre-vaccination immune metabolic interplay determines the protective antibody response to a dengue virus vaccine.

Protective immunity to dengue virus (DENV) requires antibody response to all four serotypes. Systems vaccinology identifies a multi-OMICs pre-vaccination signature and mechanisms predictive of broad antibody responses after immunization with a tetravalent live attenuated DENV vaccine candidate (Butantan-DV/TV003). Anti-inflammatory pathways, including TGF-ß signaling expressed by CD68low monocytes, and the metabolites phosphatidylcholine (PC) and phosphatidylethanolamine (PE) positively correlate with broadly neutralizing antibody responses against DENV. In contrast, expression of pro-inflammatory pathways and cytokines (IFN and IL-1) in CD68hi monocytes and primary and secondary bile acids negatively correlates with broad DENV-specific antibody responses. Induction of TGF-ß and IFNs is done respectively by PC/PE and bile acids in CD68low and CD68hi monocytes. The inhibition of viral sensing by PC/PE-induced TGF-ß is confirmed in vitro. Our studies show that the balance between metabolites and the pro- or anti-inflammatory state of innate immune cells drives broad and protective B cell response to a live attenuated dengue vaccine.

Dengue: A review of laboratory diagnostics in the vaccine age.

Background. Dengue is an important arboviral infection of considerable public health significance. It occurs in a wide global belt within a variety of tropical regions. The timely laboratory diagnosis of Dengue infection is critical to inform both clinical management and an appropriate public health response. Vaccination against Dengue virus is being introduced in some areas.Discussion. Appropriate diagnostic strategies will vary between laboratories depending on the available resources and skills. Diagnostic methods available include viral culture, the serological detection of Dengue-specific antibodies in using enzyme immunoassays (EIAs), microsphere immunoassays, haemagglutination inhibition or in lateral flow point of care tests. The results of antibody tests may be influenced by prior vaccination and exposure to other flaviviruses. The detection of non-structural protein 1 in serum (NS1) has improved the early diagnosis of Dengue and is available in point-of-care assays in addition to EIAs. Direct detection of viral RNA from blood by PCR is more sensitive than NS1 antigen detection but requires molecular skills and resources. An increasing variety of isothermal nucleic acid detection methods are in development. Timing of specimen collection and choice of test is critical to optimize diagnostic accuracy. Metagenomics and the direct detection by sequencing of viral RNA from blood offers the ability to rapidly type isolates for epidemiologic purposes.Conclusion. The impact of vaccination on immune response must be recognized as it will impact test interpretation and diagnostic algorithms.

IgG, IgM, and Nonstructural Protein 1 Response Profiles after Receipt of Tetravalent Dengue Vaccine TAK-003 in a Phase 2 Randomized Controlled Trial.

The profiles of vaccine-induced dengue antibodies may differ from those produced following natural infection and could potentially interfere with the interpretation of diagnostic tests. We assessed anti-dengue IgG and IgM antibodies, and nonstructural protein 1 antigen profiles in the serum of adults who received a single dose of the tetravalent dengue vaccine TAK-003 as either an initially developed high-dose formulation or the standard approved formulation in a phase 2 study in Singapore (#NCT02425098). Immunoglobulin G and IgM profiles during the first 30 days postvaccination varied by baseline serostatus (microneutralization assay). Nonstructural protein 1 antigen was not detected in the serum of any participants. Vaccine-induced IgG and IgM antibodies can affect serological confirmation of subsequent dengue infection in vaccinees. These results highlight the limitations of using serological tests for dengue diagnosis, particularly in a postvaccination setting, and emphasize the need for more sensitive antigen- and molecular-based testing for accurate dengue diagnosis.

Next-generation Dengue Vaccines: Leveraging Peptide-Based Immunogens and Advanced Nanoparticles as Delivery Platforms.

Dengue, caused by the dengue virus (DENV), is a prevalent arthropod-borne disease in humans and poses a significant burden on public health. Severe cases of dengue can be life-threatening. Although a licensed dengue vaccine is available, its efficacy varies across different virus serotypes and may exacerbate the disease in some seronegative recipients. Developing a safe and effective vaccine against all DENV serotypes remains challenging and requires continued research. Conventional approaches in dengue vaccine development, using live or attenuated microorganisms or parts of them often contain unnecessary epitopes, risking allergenic or autoimmune reactions. To address these challenges, innovative strategies such as peptide vaccines have been explored. Peptide vaccines offer a safer alternative by inducing specific immune responses with minimal immunogenic fragments. Chemical modification strategies of peptides have revolutionized their design, allowing for the incorporation of multi-epitope presentation, self-adjuvanting features, and self-assembling properties. These modifications enhance the antigenicity of the peptides, leading to improved vaccine efficacy. This review outlines advancements in peptide-based dengue vaccine development, leveraging nanoparticles as antigen-displaying platforms. Additionally, key immunological considerations for enhancing efficacy and safety against DENV infection have been addressed, providing insight into the next-generation of dengue vaccine development leveraging on peptide-nanoparticle technology.

Regional Variation of the CD4 and CD8 T Cell Epitopes Conserved in Circulating Dengue Viruses and Shared with Potential Vaccine Candidates.

As dengue expands globally and many vaccines are under trials, there is a growing recognition of the need for assessing T cell immunity in addition to assessing the functions of neutralizing antibodies during these endeavors. While several dengue-specific experimentally validated T cell epitopes are known, less is understood about which of these epitopes are conserved among circulating dengue viruses and also shared by potential vaccine candidates. As India emerges as the epicenter of the dengue disease burden and vaccine trials commence in this region, we have here aligned known dengue specific T cell epitopes, reported from other parts of the world with published polyprotein sequences of 107 dengue virus isolates available from India. Of the 1305 CD4 and 584 CD8 epitopes, we found that 24% and 41%, respectively, were conserved universally, whereas 27% and 13% were absent in any viral isolates. With these data, we catalogued epitopes conserved in circulating dengue viruses from India and matched them with each of the six vaccine candidates under consideration (TV003, TDEN, DPIV, CYD-TDV, DENVax and TVDV). Similar analyses with viruses from Thailand, Brazil and Mexico revealed regional overlaps and variations in these patterns. Thus, our study provides detailed and nuanced insights into regional variation that should be considered for itemization of T cell responses during dengue natural infection and vaccine design, testing and evaluation.

[Dengue vaccines, a time for cautious optimism?] / Vaccins contre la dengue, le temps de l'optimisme prudent ?

Vaccine could take a central role in the strategy to reduce the burden of dengue. The development of an effective and safe vaccine must address various immunological challenges. Several vaccines are currently in development. To date, two live-attenuated vaccines have been deployed. Both have an effectiveness that varies depending on the serotypes. The deployment of the Dengvaxia vaccine, which began in 2015, was marked by a major safety alert leading to its use being restricted to previously dengue-seropositive people over 9 years old. The Qdenga vaccine is currently being deployed. There is for now insufficient data to ensure its safety in seronegative people. Some travelers, who have previously been infected with dengue, are a group for whom a vaccination recommendation applies.

Les vaccins pourraient occuper une place centrale dans la stratégie de réduction du fardeau de la dengue. Le développement d'un vaccin efficace et sûr est complexe car il doit relever plusieurs défis immunologiques. Différents vaccins sont en développement. À ce jour, deux vaccins vivants atténués ont été déployés. Tous deux ont une efficacité qui varie selon les sérotypes. Le déploiement du vaccin Dengvaxia, débuté en 2015, a été marqué par une alerte de sécurité majeure conduisant à restreindre son usage aux personnes de plus de 9 ans, préalablement séropositives pour la dengue. Le vaccin Qdenga est en cours de déploiement. Le recul est insuffisant pour assurer son innocuité chez les séronégatifs. Certains voyageurs, ayant déjà été infectés par la dengue, constituent un groupe pour lequel une recommandation vaccinale s'applique.

A tetravalent dengue virus-like particle vaccine induces high levels of neutralizing antibodies and reduces dengue replication in non-human primates.

Dengue virus (DENV) represents a significant global health burden, with 50% of the world's population at risk of infection, and there is an urgent need for next-generation vaccines. Virus-like particle (VLP)-based vaccines, which mimic the antigenic structure of the virus but lack the viral genome, are an attractive approach. Here, we describe a dengue VLP (DENVLP) vaccine which generates a neutralizing antibody response against all four DENV serotypes in 100% of immunized non-human primates for up to 1 year. Additionally, DENVLP vaccination produced no ADE response against any of four DENV serotypes in vitro. DENVLP vaccination reduces viral replication in a non-human primate challenge model. We also show that transfer of purified IgG from immunized monkeys into immunodeficient mice protects against subsequent lethal DENV challenge, indicating a humoral mechanism of protection. These results indicate that this DENVLP vaccine is immunogenic and can be considered for clinical evaluation. Immunization of non-human primates with a tetravalent DENVLP vaccine induces high levels of neutralizing antibodies and reduces the severity of infection for all four dengue serotypes.IMPORTANCEDengue is a viral disease that infects nearly 400 million people worldwide and causes dengue hemorrhagic fever, which is responsible for 10,000 deaths each year. Currently, there is no therapeutic drug licensed to treat dengue infection, which makes the development of an effective vaccine essential. Virus-like particles (VLPs) are a safe and highly immunogenic platform that can be used in young children, immunocompromised individuals, as well as healthy adults. In this study, we describe the development of a dengue VLP vaccine and demonstrate that it induces a robust immune response against the dengue virus for over 1 year in monkeys. The immunity induced by this vaccine reduced live dengue infection in both murine and non-human primate models. These results indicate that our dengue VLP vaccine is a promising vaccine candidate.

Super epitope dengue vaccine instigated serotype independent immune protection in-silico.

Dengue becomes the most common life-threatening infectious arbovirus disease globally, with prevalence in the tropical and subtropical areas. The major clinical features include dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS), a condition of hypovolemic shock. Four different serotypes of the dengue virus, known as dengue virus serotype (DENV)- 1, 2, 3 and 4 can infect humans. Only one vaccine is available in the market, named Dengvaxia by Sanofi Pasteur, but there is no desired outcome of this treatment due the antibody dependent enhancement (ADE) of the multiple dengue serotypes. As of now, there is no cure against dengue disease. Our goal in this work was to create a subunit vaccine based on several epitopes that would be effective against every serotype of the dengue virus. Here, computational methods like- immunoinformatics and bioinformatics were implemented to find out possible dominant epitopes. A total of 21 epitopes were chosen using various in-silico techniques from the expected 133 major histocompatibility complex (MHC)- I and major histocompatibility complex (MHC)- II epitopes, along with 95 B-cell epitopes which were greatly conserved. Immune stimulant, non-allergenic and non-toxic immunodominant epitopes (super epitopes) with a suitable adjuvant (Heparin-Binding Hemagglutinin Adhesin, HBHA) were used to construct the vaccine. Following the physicochemical analysis, vaccine construct was docked with Toll-like receptors (TLRs) to predict the immune stimulation. Consequently, the optimal docked complex that demonstrated the least amount of ligand-receptor complex deformability was used to conduct the molecular dynamics analysis. By following the codon optimization, the final vaccine molecule was administered into an expressing vector to perform in-silico cloning. The robust immune responses were generated in the in-silico immune simulation analysis. Hence, this study provides a hope to control the dengue infections. For validation of the immune outcomes, in-vitro as well as in-vivo investigations are essential.