scholarly journals SARS-CoV-2 infection induces protective immunity and limits transmission in Syrian hamsters

2021 ◽  
Vol 4 (4) ◽  
pp. e202000886 ◽  
Author(s):  
Prabhuanand Selvaraj ◽  
Christopher Z Lien ◽  
Shufeng Liu ◽  
Charles B Stauft ◽  
Ivette A Nunez ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Vaccine Development ◽  
Severe Disease ◽  
Laboratory Animals ◽  
Critical Question ◽  
Hamster Model ◽  
Public Health Policies ◽  
Viral Loads ◽  
Log Reduction

A critical question in understanding the immunity to SARS-COV-2 is whether recovered patients are protected against re-challenge and transmission upon second exposure. We developed a Syrian hamster model in which intranasal inoculation of just 100 TCID50 virus caused viral pneumonia. Aged hamsters developed more severe disease and even succumbed to SARS-CoV-2 infection, representing the first lethal model using genetically unmodified laboratory animals. After initial viral clearance, the hamsters were re-challenged with 105 TCID50 SARS-CoV-2 and displayed more than 4 log reduction in median viral loads in both nasal washes and lungs in comparison to primary infections. Most importantly, re-challenged hamsters were unable to transmit virus to naïve hamsters, and this was accompanied by the presence of neutralizing antibodies. Altogether, these results show that SARS-CoV-2 infection induces protective immunity that not only prevents re-exposure but also limits transmission in hamsters. These findings may help guide public health policies and vaccine development and aid evaluation of effective vaccines against SARS-CoV-2.

scholarly journals Contributions of the Avian Influenza Virus HA, NA, and M2 Surface Proteins to the Induction of Neutralizing Antibodies and Protective Immunity

2009 ◽  
Vol 84 (5) ◽  
pp. 2408-2420 ◽  
Author(s):  
Baibaswata Nayak ◽  
Sachin Kumar ◽  
Joshua M. DiNapoli ◽  
Anandan Paldurai ◽  
Daniel R. Perez ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Reverse Genetics ◽  
Severe Disease ◽  
Serum Antibody ◽  
Surface Proteins ◽  
Serum Antibodies

ABSTRACT Highly pathogenic avian influenza virus (HPAIV) subtype H5N1 causes severe disease and mortality in poultry. Increased transmission of H5N1 HPAIV from birds to humans is a serious threat to public health. We evaluated the individual contributions of each of the three HPAIV surface proteins, namely, the hemagglutinin (HA), the neuraminidase (NA), and the M2 proteins, to the induction of HPAIV-neutralizing serum antibodies and protective immunity in chickens. Using reverse genetics, three recombinant Newcastle disease viruses (rNDVs) were engineered, each expressing the HA, NA, or M2 protein of H5N1 HPAIV. Chickens were immunized with NDVs expressing a single antigen (HA, NA, and M2), two antigens (HA+NA, HA+M2, and NA+M2), or three antigens (HA+NA+M2). Immunization with HA or NA induced high titers of HPAIV-neutralizing serum antibodies, with the response to HA being greater, thus identifying HA and NA as independent neutralization antigens. M2 did not induce a detectable neutralizing serum antibody response, and inclusion of M2 with HA or NA reduced the magnitude of the response. Immunization with HA alone or in combination with NA induced complete protection against HPAIV challenge. Immunization with NA alone or in combination with M2 did not prevent death following challenge, but extended the time period before death. Immunization with M2 alone had no effect on morbidity or mortality. Thus, there was no indication that M2 is immunogenic or protective. Furthermore, inclusion of NA in addition to HA in a vaccine preparation for chickens may not enhance the high level of protection provided by HA.

scholarly journals A novel antigenic site spanning domains I and III of the Zika virus envelope glycoprotein is the target of strongly neutralizing human monoclonal antibodies

2020 ◽  
Author(s):  
Stephen Graham ◽  
Huy A. Tu ◽  
Benjamin D. McElvany ◽  
Nancy R. Graham ◽  
Ariadna Grinyo ◽  
...  
Keyword(s):  
Zika Virus ◽  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Severe Disease ◽  
Human Monoclonal Antibody ◽  
Antigenic Site ◽  
Viral Envelope ◽  
Virus Envelope ◽  
Human Antibodies

AbstractZika virus (ZIKV), a mosquito-transmitted flavivirus, caused a large epidemic in Latin America between 2015 and 2017. Effective ZIKV vaccines and treatments are urgently needed to prevent future epidemics and severe disease sequelae. People infected with ZIKV develop strongly neutralizing antibodies linked to viral clearance and durable protective immunity. To understand mechanisms of protective immunity and to support the development of ZIKV vaccines, here we characterize the properties of a strongly neutralizing antibody, B11F, isolated from a recovered ZIKV patient. Our results indicate that B11F targets a complex epitope on the virus that spans domains I and III of the envelope glycoprotein. While previous studies point to quaternary epitopes centered on domain II of ZIKV E glycoprotein as targets of strongly neutralizing and protective human antibodies, we uncover a new site spanning domain I and III as a target of strongly neutralizing human antibodies.ImportancePeople infected with Zika virus develop durable neutralizing antibodies that prevent repeat infections. In the current study, we characterize a ZIKV-neutralizing human monoclonal antibody isolated from a patient after recovery. Our studies establish a novel site on the viral envelope targeted by human neutralizing antibodies. Our results are relevant to understanding how antibodies block infection and for guiding the design and evaluation of candidate vaccines.

scholarly journals Flexible RSV prefusogenic fusion glycoprotein exposes multiple neutralizing epitopes that may collectively contribute to protective immunity

2020 ◽  
Author(s):  
Nita Patel ◽  
Jing-Hui Tian ◽  
Rhonda Flores ◽  
Kelsey Jacobson ◽  
Michelle Walker ◽  
...  
Keyword(s):  
B Cell ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Quaternary Structure ◽  
Vaccine Development ◽  
High Titer ◽  
Treatment Options ◽  
Fusion Glycoprotein ◽  
Syncytial Virus ◽  
Neutralizing Epitopes

AbstractHuman respiratory syncytial virus (RSV) is a significant cause of lower respiratory tract infection in infants, young children, and older adults. There is no licensed vaccine and prophylactic treatment options are limited and not widely available in developing countries with the greatest disease burden. The RSV fusion (F) glycoprotein is a primary target of host immunity and thus a major focus for vaccine development. The native F glycoprotein structure is flexible and undergoes significant rearrangements from the metastable prefusion to a stable postfusion structure with neutralizing epitopes on intermediate structures. We hypothesize trimeric vaccine strategies that recapitulate the breathable F quaternary structure, and provide accessibility of B-cells to epitopes on intermediate conformations, may collectively contribute to protective immunity, while ridge prefusion F structures restrict access to key protective epitopes. To test this hypothesis, we used the near full-length native prefusogenic F as a backbone to construct three prefusion F variants with substitutions in the hydrophobic head cavity: 1) disulfide bond double mutant (DS), 2) space filling hydrophobic amino acid substitutions (Cav1), and 3) DS plus Cav1 substitutions (DS-Cav1). In this study, we compared the immunogenicity of prefusogenic F to the immunogenicity of the prefusion F variants in two animal models. Native prefusogenic F was significantly more immunogenic producing high titer antibodies to prefusogenic, prefusion, and postfusion F structures compared to animals immunized with prefusion F DS or DS-Cav1. Importantly, native prefusogenic F elicited antibodies that targeted neutralizing epitopes including prefusion-specific site zero (Ø) and V as well as conformation-independent neutralizing sites II and IV. Immunization with prefusion F DS or DS-Cav1 elicited antibodies primarily targeting antigenic sites Ø and V with little or no detectable antibodies to other key neutralizing sites. Animals immunized with native prefusogenic F also had significantly higher neutralizing antibodies that cross-neutralized RSV A and B subtypes while immunization with DS or DS-Cav1 elicited neutralizing antibodies primarily to the A subtype. We conclude that breathable trimeric vaccines that closely mimic the native F-structure, and incorporate strategies for B-cell accessibility to protective epitopes, are important considerations for vaccine design. F structures locked in a single conformation restrict B-cell access to neutralizing epitopes that may collectively contribute to destabilizing F-trimers important for broad protection. These results also have implications for vaccine strategies targeting other type 1 integral membrane proteins.

scholarly journals Nonglycosylated G-Protein Vaccine Protects against Homologous and Heterologous Respiratory Syncytial Virus (RSV) Challenge, while Glycosylated G Enhances RSV Lung Pathology and Cytokine Levels

2015 ◽  
Vol 89 (16) ◽  
pp. 8193-8205 ◽  
Author(s):  
Sandra Fuentes ◽  
Elizabeth M. Coyle ◽  
Hana Golding ◽  
Surender Khurana
Keyword(s):  
Respiratory Syncytial Virus ◽  
G Protein ◽  
Mammalian Cells ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Protective Efficacy ◽  
Lung Pathology ◽  
Content Type ◽  
Viral Loads ◽  
Syncytial Virus

ABSTRACTNew efforts are under way to develop a vaccine against respiratory syncytial virus (RSV) that will provide protective immunity without the potential for vaccine-associated disease enhancement such as that observed in infants following vaccination with formalin-inactivated RSV vaccine. In addition to the F fusion protein, the G attachment surface protein is a target for neutralizing antibodies and thus represents an important vaccine candidate. However, glycosylated G protein expressed in mammalian cells has been shown to induce pulmonary eosinophilia upon RSV infection in a mouse model. In the current study, we evaluated in parallel the safety and protective efficacy of the RSV A2 recombinant unglycosylated G protein ectodomain (amino acids 67 to 298) expressed inEscherichia coli(REG) and those of glycosylated G produced in mammalian cells (RMG) in a mouse RSV challenge model. Vaccination with REG generated neutralizing antibodies against RSV A2 in 7/11 BALB/c mice, while RMG did not elicit neutralizing antibodies. Total serum binding antibodies against the recombinant proteins (both REG and RMG) were measured by surface plasmon resonance (SPR) and were found to be >10-fold higher for REG- than for RMG-vaccinated animals. Reduction of lung viral loads to undetectable levels after homologous (RSV-A2) and heterologous (RSV-B1) viral challenge was observed in 7/8 animals vaccinated with REG but not in RMG-vaccinated animals. Furthermore, enhanced lung pathology and elevated Th2 cytokines/chemokines were observed exclusively in animals vaccinated with RMG (but not in those vaccinated with REG or phosphate-buffered saline [PBS]) after homologous or heterologous RSV challenge. This study suggests that bacterially produced unglycosylated G protein could be developed alone or as a component of a protective vaccine against RSV disease.IMPORTANCENew efforts are under way to develop vaccines against RSV that will provide protective immunity without the potential for disease enhancement. The G attachment protein represents an important candidate for inclusion in an effective RSV vaccine. In the current study, we evaluated the safety and protective efficacy of the RSV A2 recombinant unglycosylated G protein ectodomain produced inE. coli(REG) and those of glycosylated G produced in mammalian cells (RMG) in a mouse RSV challenge model (strains A2 and B1). The unglycosylated G generated high protective immunity and no lung pathology, even in animals that lacked anti-RSV neutralizing antibodies prior to RSV challenge. Control of viral loads correlated with antibody binding to the G protein. In contrast, the glycosylated G protein provided poor protection and enhanced lung pathology after RSV challenge. Therefore, bacterially produced unglycosylated G protein holds promise as an economical approach to a protective vaccine against RSV.

scholarly journals Protective Immunity against SARS Subunit Vaccine Candidates Based on Spike Protein: Lessons for Coronavirus Vaccine Development

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Atin Khalaj-Hedayati
Keyword(s):  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Subunit Vaccine ◽  
Vaccine Development ◽  
Spike Protein ◽  
Effective Vaccine ◽  
Universal Vaccine ◽  
Health Security ◽  
Vaccine Candidates ◽  
Novel Coronavirus

The recent outbreak of the novel coronavirus disease, COVID-19, has highlighted the threat that highly pathogenic coronaviruses have on global health security and the imminent need to design an effective vaccine for prevention purposes. Although several attempts have been made to develop vaccines against human coronavirus infections since the emergence of Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) in 2003, there is no available licensed vaccine yet. A better understanding of previous coronavirus vaccine studies may help to design a vaccine for the newly emerged virus, SARS-CoV-2, that may also cover other pathogenic coronaviruses as a potentially universal vaccine. In general, coronavirus spike protein is the major antigen for the vaccine design as it can induce neutralizing antibodies and protective immunity. By considering the high genetic similarity between SARS-CoV and SARS-CoV-2, here, protective immunity against SARS-CoV spike subunit vaccine candidates in animal models has been reviewed to gain advances that can facilitate coronavirus vaccine development in the near future.

scholarly journals Defining levels of dengue virus serotype-specific neutralizing antibodies induced by a live attenuated tetravalent dengue vaccine (TAK-003)

2020 ◽  
Author(s):  
Laura J. White ◽  
Ellen Young ◽  
Mark Stoops ◽  
Sandra Henein ◽  
Ralph S. Baric ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Severe Disease ◽  
Effective Vaccine ◽  
Dengue Vaccine ◽  
Unique Type ◽  
Vaccine Component ◽  
Virus Serotype

AbstractThe four dengue virus serotypes (DENV1-4) infect several hundred million people each year living in tropical and sub-tropical regions. Clinical development of DENV vaccines is difficult because immunity to a single serotype increases risk of severe disease during a second infection with a new serotype. Leading vaccines are based on tetravalent formulations to induce simultaneous and balanced protective immunity to all 4 serotypes. TAK-003 is a tetravalent live attenuated dengue vaccine candidate developed by Takeda Vaccines Inc, which is currently being evaluated in phase 3 efficacy trials. Here, we use antibody depletion methods and chimeric, epitope transplant DENVs to characterize the specificity of neutralizing antibodies in dengue-naïve adults and non-human primates immunized with TAK-003. Our results demonstrate that TAK-003 induced high levels of DENV2 neutralizing antibodies that recognized unique (type-specific) epitopes on DENV2. In contrast, most vaccinated subjects developed lower levels of DENV1, DENV3 and DENV4 neutralizing antibodies that mainly targeted epitopes that were conserved (cross-reactive) between serotypes. We conclude that the DENV2 component in the vaccine is immunodominant because of the high levels of serum neutralizing antibodies targeting type-specific epitopes. We also conclude that DENV1, 3 and 4 vaccine components are less immunogenic because most study subjects did not develop type-specific serum neutralizing antibodies to these serotypes. While DENV vaccine development has been guided by the presence of neutralizing antibodies to each serotype as a benchmark, our results indicate that the presence of neutralizing antibodies alone are not a reliable indicator of the immunogenicity of each vaccine component.Author summaryThe development of tetravalent dengue vaccines has been guided by neutralizing antibodies to each serotype as a correlate of safe and effective vaccine induced immunity. However, the absolute levels of neutralizing antibodies to each serotype has proven to be an unreliable correlate of protection. Levels of antibodies to epitopes that are unique to each serotype, which are measures of immunity independently stimulated by each vaccine component, rather than total quantity of neutralizing antibodies, are likely to be better correlates of protection. Here, we mapped the specificity of antibodies induced by the Takeda tetravalent dengue vaccine TAK-003 in monkeys and humans with no prior immunity to dengue. The TAK-003 vaccine induces high levels of serotype 2 specific neutralizing antibodies that map to known protective epitopes. In contrast, the serotype 1, 3 and 4 neutralizing antibody responses are lower and mainly consist of cross-reactive antibodies binding to epitopes conserved between serotypes. These heterotypic antibodies, which are most likely derived from the serotype 2 component, may not provide long term protection in vivo.

scholarly journals A Novel Recombinant Virus-Like Particles Displaying B and T Cell Epitopes of Japanese Encephalitis Virus Offers Protective Immunity in Mice and Guinea Pigs

Vaccines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 980
Author(s):  
Muhammad Naveed Anwar ◽  
Chunying Jiang ◽  
Di Di ◽  
Junjie Zhang ◽  
Shuang Guo ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Guinea Pigs ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Vaccine Development ◽  
Amino Acid Sequences ◽  
Encephalitis Virus ◽  
Potential Candidate ◽  
Virus Like Particles

Virus-like particles (VLPs) are non-replicative vectors for the delivery of heterologous epitopes and are considered one of the most potent inducers of cellular and humoral immune responses in mice and guinea pigs. In the present study, VLP-JEVe was constructed by the insertion of six Japanese encephalitis virus (JEV) envelope protein epitopes into different surface loop regions of PPV VP2 by the substitution of specific amino acid sequences without altering the assembly of the virus; subsequently, the protective efficacy of this VLP-JEVe was evaluated against JEV challenge in mice and guinea pigs. Mice immunized with the VLP-JEVe antigen developed high titers of neutralizing antibodies and 100% protection against lethal JEV challenge. The neutralizing and hemagglutination inhibition (HI) antibody responses were also induced in guinea pigs vaccinated with VLP-JEVe. In addition, immunization with VLP-JEVe in mice induced effective neutralizing antibodies and protective immunity against PPV (porcine parvovirus) challenge in guinea pigs. These studies suggest that VLP-JEVe produced as described here could be a potential candidate for vaccine development.

scholarly journals Long-term protection of rhesus macaques from Zika virus reinfection

2019 ◽  
Author(s):  
Gage K. Moreno ◽  
Christina M. Newman ◽  
Michelle R. Koenig ◽  
Mariel S. Mohns ◽  
Andrea M. Weiler ◽  
...  
Keyword(s):  
Zika Virus ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Vaccine Development ◽  
Rhesus Macaques ◽  
Herd Immunity ◽  
Minimal Length ◽  
Plasma Viremia ◽  
Zikv Infection ◽  
Congenital Zika Syndrome

AbstractBy the end of the 2016 Zika virus (ZIKV) outbreak, it is estimated that there were up to 100 million infections in the Americas. In approximately one in seven infants born to mothers infected during pregnancy, ZIKV has been linked to microcephaly, developmental delays, or other congenital disorders collectively known as congenital Zika syndrome (CZS). Guillain-Barré syndrome (GBS) in ZIKV infected adults. It is a global health priority to develop a vaccine against ZIKV that elicits long-lasting immunity, however, the durability of immunity to ZIKV is unknown. Previous studies in mice and nonhuman primates have been crucial in vaccine development but have not defined the duration of immunity generated by ZIKV infection. In this study, we rechallenged five rhesus macaques with ZIKV two years after a primary ZIKV infection. We show that primary ZIKV infection generates high titers of neutralizing antibodies (nAbs) that protect from detectable plasma viremia following rechallenge and persist for at least 27 months. While additional longitudinal studies are necessary with longer time frames, this study establishes a new experimentally defined minimal length of protective ZIKV immunity.Author SummaryZIKV emerged as a vector-borne pathogen capable of causing illness in infected adults and congenital birth defects in infants born to mothers infected during pregnancy. Despite the drop in ZIKV cases since the 2015-16 epidemic, questions concerning the prevalence and longevity of protective immunity have left vulnerable communities fearful that they may become the center of next ZIKV outbreak. While pre-existing herd immunity in regions of past outbreaks may dampen the potential for future outbreaks to occur, we currently do not know the longevity of protective immunity to ZIKV after a person becomes infected. Here, we establish a new experimentally defined minimal length of protective ZIKV immunity. We show that five rhesus macaques initially infected with ZIKV two years prior to rechallenge elicit a durable immune response that protected from detectable plasma viremia. While this work establishes a new minimal length of protective immunity, additional studies are necessary to define the maximum length of protective immunity following ZIKV infection.

scholarly journals Engineered Dengue Virus Domain III Proteins Elicit Cross-Neutralizing Antibody Responses in Mice

2018 ◽  
Vol 92 (18) ◽  
Author(s):  
Julia C. Frei ◽  
Ariel S. Wirchnianski ◽  
Jennifer Govero ◽  
Olivia Vergnolle ◽  
Kimberly A. Dowd ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Neutralizing Antibodies ◽  
Primary Infection ◽  
Vaccine Development ◽  
Secondary Infection ◽  
Severe Disease ◽  
Febrile Illness ◽  
Neutralizing Antibody ◽  
Immunogen Design ◽  
Domain Iii

ABSTRACTDengue virus is the most globally prevalent mosquito-transmitted virus. Primary infection with one of four cocirculating serotypes (DENV-1 to -4) causes a febrile illness, but secondary infection with a heterologous serotype can result in severe disease, due in part to antibody-dependent enhancement of infection (ADE). In ADE, cross-reactive but nonneutralizing antibodies, or subprotective levels of neutralizing antibodies, promote uptake of antibody-opsonized virus in Fc-γ receptor-positive cells. Thus, elicitation of broadly neutralizing antibodies (bNAbs), but not nonneutralizing antibodies, is desirable for dengue vaccine development. Domain III of the envelope glycoprotein (EDIII) is targeted by bNAbs and thus is an attractive immunogen. However, immunization with EDIII results in sera with limited neutralization breadth. We developed “resurfaced” EDIII immunogens (rsDIIIs) in which the A/G strand epitope that is targeted by bNAb 4E11 is maintained but less desirable epitopes are masked. RsDIIIs bound 4E11, but not serotype-specific or nonneutralizing antibodies. One rsDIII and, unexpectedly, wild-type (WT) DENV-2 EDIII elicited cross-neutralizing antibody responses against DENV-1 to -3 in mice. While these sera were cross-neutralizing, they were not sufficiently potent to protect AG129 immunocompromised mice at a dose of 200 μl (50% focus reduction neutralization titer [FRNT50], ∼1:60 to 1:130) against mouse-adapted DENV-2. Our results provide insight into immunogen design strategies based on EDIII.IMPORTANCEDengue virus causes approximately 390 million infections per year. Primary infection by one serotype causes a self-limiting febrile illness, but secondary infection by a heterologous serotype can result in severe dengue syndrome, which is characterized by hemorrhagic fever and shock syndrome. This severe disease is thought to arise because of cross-reactive, non- or poorly neutralizing antibodies from the primary infection that are present in serum at the time of secondary infection. These cross-reactive antibodies enhance the infection rather than controlling it. Therefore, induction of a broadly and potently neutralizing antibody response is desirable for dengue vaccine development. Here, we explore a novel strategy for developing immunogens based on domain III of the E glycoprotein, where undesirable epitopes (nonneutralizing or nonconserved) are masked by mutation. This work provides fundamental insight into the immune response to domain III that can be leveraged for future immunogen design.

scholarly journals Defining levels of dengue virus serotype-specific neutralizing antibodies induced by a live attenuated tetravalent dengue vaccine (TAK-003)

2021 ◽  
Vol 15 (3) ◽  
pp. e0009258
Author(s):  
Laura J. White ◽  
Ellen F. Young ◽  
Mark J. Stoops ◽  
Sandra R. Henein ◽  
Elizabeth C. Adams ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Severe Disease ◽  
Dengue Vaccine ◽  
Unique Type ◽  
Tropical Regions ◽  
Efficacy Trials ◽  
Virus Serotype ◽  
Dengue Virus Serotypes

The four dengue virus serotypes (DENV1-4) infect several hundred million people each year living in tropical and sub-tropical regions. Clinical development of DENV vaccines is difficult because immunity to a single serotype increases risk of severe disease during a second infection with a new serotype. Leading vaccines are based on tetravalent formulations to induce simultaneous and balanced protective immunity to all 4 serotypes. TAK-003 is a tetravalent live attenuated dengue vaccine candidate developed by Takeda Vaccines Inc, which is currently being evaluated in phase 3 efficacy trials. Here, we use antibody depletion methods and chimeric, epitope transplant DENVs to characterize the specificity of neutralizing antibodies in dengue-naïve adults and non-human primates immunized with TAK-003. Our results demonstrate that TAK-003 induced high levels of DENV2 neutralizing antibodies that recognized unique (type-specific) epitopes on DENV2. In contrast, most vaccinated subjects developed lower levels of DENV1, DENV3 and DENV4 neutralizing antibodies that mainly targeted epitopes that were conserved (cross-reactive) between serotypes. Trial Registration: ClinicalTrials.gov NCT02425098.

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