scholarly journals Induction of Immune Responses in Mice and Monkeys to Ebola Virus after Immunization with Liposome-Encapsulated Irradiated Ebola Virus: Protection in Mice Requires CD4+ T Cells

2002 ◽  
Vol 76 (18) ◽  
pp. 9176-9185 ◽  
Author(s):  
Mangala Rao ◽  
Mike Bray ◽  
Carl R. Alving ◽  
Peter Jahrling ◽  
Gary R. Matyas
Keyword(s):  
T Lymphocytes ◽  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Ebola Virus ◽  
Protective Efficacy ◽  
Hemorrhagic Fever ◽  
Surface Glycoprotein ◽  
Antibody Treatment ◽  
Amino Terminal ◽  
Monoclonal Antibody Treatment

ABSTRACT Ebola Zaire virus (EBO-Z) causes severe hemorrhagic fever in humans, with a high mortality rate. It is thought that a vaccine against EBO-Z may have to induce both humoral and cell-mediated immune responses to successfully confer protection. Because it is known that liposome-encapsulated antigens induce both antibody and cellular responses, we evaluated the protective efficacy of liposome-encapsulated irradiated EBO-Z [L(EV)], which contains all of the native EBO-Z proteins. In a series of experiments, mice immunized intravenously with L(EV) were completely protected (94/94 mice) against illness and death when they were challenged with a uniformly lethal mouse-adapted variant of EBO-Z. In contrast, only 55% of mice immunized intravenously with nonencapsulated irradiated virus (EV) survived challenge, and all became ill. Treatment with anti-CD4 antibodies before or during immunization with L(EV) eliminated protection, while treatment with anti-CD8 antibodies had no effect, thus indicating a requirement for CD4+ T lymphocytes for successful immunization. On the other hand, treatment with either anti-CD4 or anti-CD8 antibodies after immunization did not abolish the protection. After immunization with L(EV), antigen-specific gamma interferon (IFNγ)-secreting CD4+ T lymphocytes were induced as analyzed by enzyme-linked immunospot assay. Anti-CD4 monoclonal antibody treatment abolished IFNγ production (80 to 90% inhibition compared to that for untreated mice). Mice immunized with L(EV), but not EV, developed cytotoxic T lymphocytes specific to two peptides (amino acids [aa] 161 to 169 and aa 231 to 239) present in the amino-terminal end of the EBO-Z surface glycoprotein. Because of the highly successful results in the mouse model, L(EV) was also tested in three cynomolgus monkeys. Although immunization of the monkeys with L(EV)-induced virus-neutralizing antibodies against EBO-Z caused a slight delay in the onset of illness, it did not prevent death.

scholarly journals Successful Topical Respiratory Tract Immunization of Primates against Ebola Virus

2007 ◽  
Vol 81 (12) ◽  
pp. 6379-6388 ◽  
Author(s):  
Alexander Bukreyev ◽  
Pierre E. Rollin ◽  
Mallory K. Tate ◽  
Lijuan Yang ◽  
Sherif R. Zaki ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Ebola Virus ◽  
Protective Efficacy ◽  
Hemorrhagic Fever ◽  
Surface Glycoprotein ◽  
Respiratory Pathogen ◽  
Viral Hemorrhagic Fever ◽  
Primate Model ◽  
Challenge Virus ◽  
Virus Challenge

ABSTRACT Ebola virus causes outbreaks of severe viral hemorrhagic fever with high mortality in humans. The virus is highly contagious and can be transmitted by contact and by the aerosol route. These features make Ebola virus a potential weapon for bioterrorism and biological warfare. Therefore, a vaccine that induces both systemic and local immune responses in the respiratory tract would be highly beneficial. We evaluated a common pediatric respiratory pathogen, human parainfluenza virus type 3 (HPIV3), as a vaccine vector against Ebola virus. HPIV3 recombinants expressing the Ebola virus (Zaire species) surface glycoprotein (GP) alone or in combination with the nucleocapsid protein NP or with the cytokine adjuvant granulocyte-macrophage colony-stimulating factor were administered by the respiratory route to rhesus monkeys—in which HPIV3 infection is mild and asymptomatic—and were evaluated for immunogenicity and protective efficacy against a highly lethal intraperitoneal challenge with Ebola virus. A single immunization with any construct expressing GP was moderately immunogenic against Ebola virus and protected 88% of the animals against severe hemorrhagic fever and death caused by Ebola virus. Two doses were highly immunogenic, and all of the animals survived challenge and were free of signs of disease and of detectable Ebola virus challenge virus. These data illustrate the feasibility of immunization via the respiratory tract against the hemorrhagic fever caused by Ebola virus. To our knowledge, this is the first study in which topical immunization through respiratory tract achieved prevention of a viral hemorrhagic fever infection in a primate model.

scholarly journals Safety and Immunogenicity of Heterologous and Homologous 2-Dose Regimens of Adenovirus Serotype 26– and Modified Vaccinia Ankara–Vectored Ebola Vaccines: A Randomized, Controlled Phase 1 Study

2020 ◽  
Author(s):  
Neil Goldstein ◽  
Viki Bockstal ◽  
Stephan Bart ◽  
Kerstin Luhn ◽  
Cynthia Robinson ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Ebola Virus ◽  
Phase 1 ◽  
Booster Vaccination ◽  
Controlled Study ◽  
Adenovirus Serotype ◽  
Cellular Immune Responses ◽  
High Doses ◽  
Cellular Immune

Abstract Background This phase 1 placebo-controlled study assessed the safety and immunogenicity of 2-dose regimens of Ad26.ZEBOV (adenovirus serotype 26 [Ad26]) and MVA-BN-Filo (modified vaccinia Ankara [MVA]) vaccines with booster vaccination at day 360. Methods Healthy US adults (N = 164) randomized into 10 groups received saline placebo or standard or high doses of Ad26 or MVA in 2-dose regimens at 7-, 14-, 28-, or 56-day intervals; 8 groups received booster Ad26 or MVA vaccinations on day 360. Participants reported solicited and unsolicited reactogenicity; we measured immunoglobulin G binding, neutralizing antibodies and cellular immune responses to Ebola virus glycoprotein. Results All regimens were well tolerated with no serious vaccine-related adverse events. Heterologous (Ad26,MVA [dose 1, dose 2] or MVA,Ad26) and homologous (Ad26,Ad26) regimens induced humoral and cellular immune responses 21 days after dose 2; responses were higher after heterologous regimens. Booster vaccination elicited anamnestic responses in all participants. Conclusions Both heterologous and homologous Ad26,MVA Ebola vaccine regimens are well tolerated in healthy adults, regardless of interval or dose level. Heterologous 2-dose Ad26,MVA regimens containing an Ebola virus insert induce strong, durable humoral and cellular immune responses. Immunological memory was rapidly recalled by booster vaccination, suggesting that Ad26 booster doses could be considered for individuals at risk of Ebola infection, who previously received the 2-dose regimen.

scholarly journals Macaque Monoclonal Antibodies Targeting Novel Conserved Epitopes within Filovirus Glycoprotein

2015 ◽  
Vol 90 (1) ◽  
pp. 279-291 ◽  
Author(s):  
Zhen-Yong Keck ◽  
Sven G. Enterlein ◽  
Katie A. Howell ◽  
Hong Vu ◽  
Sergey Shulenin ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Nonhuman Primates ◽  
Ebola Virus ◽  
Virus Disease ◽  
Protective Efficacy ◽  
Hemorrhagic Fever ◽  
Marburg Virus ◽  
Human Pathogens ◽  
Content Type ◽  
The Core

ABSTRACTFiloviruses cause highly lethal viral hemorrhagic fever in humans and nonhuman primates. Current immunotherapeutic options for filoviruses are mostly specific to Ebola virus (EBOV), although other members ofFiloviridaesuch as Sudan virus (SUDV), Bundibugyo virus (BDBV), and Marburg virus (MARV) have also caused sizeable human outbreaks. Here we report a set of pan-ebolavirus and pan-filovirus monoclonal antibodies (MAbs) derived from cynomolgus macaques immunized repeatedly with a mixture of engineered glycoproteins (GPs) and virus-like particles (VLPs) for three different filovirus species. The antibodies recognize novel neutralizing and nonneutralizing epitopes on the filovirus glycoprotein, including conserved conformational epitopes within the core regions of the GP1 subunit and a novel linear epitope within the glycan cap. We further report the first filovirus antibody binding to a highly conserved epitope within the fusion loop of ebolavirus and marburgvirus species. One of the antibodies binding to the core GP1 region of all ebolavirus species and with lower affinity to MARV GP cross neutralized both SUDV and EBOV, the most divergent ebolavirus species. In a mouse model of EBOV infection, this antibody provided 100% protection when administered in two doses and partial, but significant, protection when given once at the peak of viremia 3 days postinfection. Furthermore, we describe novel cocktails of antibodies with enhanced protective efficacy compared to individual MAbs. In summary, the present work describes multiple novel, cross-reactive filovirus epitopes and innovative combination concepts that challenge the current therapeutic models.IMPORTANCEFiloviruses are among the most deadly human pathogens. The 2014-2015 outbreak of Ebola virus disease (EVD) led to more than 27,000 cases and 11,000 fatalities. While there are five species ofEbolavirusand several strains of marburgvirus, the current immunotherapeutics primarily target Ebola virus. Since the nature of future outbreaks cannot be predicted, there is an urgent need for therapeutics with broad protective efficacy against multiple filoviruses. Here we describe a set of monoclonal antibodies cross-reactive with multiple filovirus species. These antibodies target novel conserved epitopes within the envelope glycoprotein and exhibit protective efficacy in mice. We further present novel concepts for combination of cross-reactive antibodies against multiple epitopes that show enhanced efficacy compared to monotherapy and provide complete protection in mice. These findings set the stage for further evaluation of these antibodies in nonhuman primates and development of effective pan-filovirus immunotherapeutics for use in future outbreaks.

scholarly journals Immunization with DNA Plasmids Coding for Crimean-Congo Hemorrhagic Fever Virus Capsid and Envelope Proteins and/or Virus-Like Particles Induces Protection and Survival in Challenged Mice

2017 ◽  
Vol 91 (10) ◽  
Author(s):  
Jorma Hinkula ◽  
Stéphanie Devignot ◽  
Sara Åkerström ◽  
Helen Karlberg ◽  
Eva Wattrang ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Dna Vaccine ◽  
Neutralizing Antibodies ◽  
Hemorrhagic Fever ◽  
Fever Virus ◽  
Vaccine Candidates ◽  
Th1 Response ◽  
Crimean Congo Hemorrhagic Fever ◽  
Hemorrhagic Fever Virus

ABSTRACT Crimean-Congo hemorrhagic fever virus (CCHFV) is a bunyavirus causing severe hemorrhagic fever disease in humans, with high mortality rates. The requirement of a high-containment laboratory and the lack of an animal model hampered the study of the immune response and protection of vaccine candidates. Using the recently developed interferon alpha receptor knockout (IFNAR−/−) mouse model, which replicates human disease, we investigated the immunogenicity and protection of two novel CCHFV vaccine candidates: a DNA vaccine encoding a ubiquitin-linked version of CCHFV Gc, Gn, and N and one using transcriptionally competent virus-like particles (tc-VLPs). In contrast to most studies that focus on neutralizing antibodies, we measured both humoral and cellular immune responses. We demonstrated a clear and 100% efficient preventive immunity against lethal CCHFV challenge with the DNA vaccine. Interestingly, there was no correlation with the neutralizing antibody titers alone, which were higher in the tc-VLP-vaccinated mice. However, the animals with a lower neutralizing titer, but a dominant cell-mediated Th1 response and a balanced Th2 response, resisted the CCHFV challenge. Moreover, we found that in challenged mice with a Th1 response (immunized by DNA/DNA and boosted by tc-VLPs), the immune response changed to Th2 at day 9 postchallenge. In addition, we were able to identify new linear B-cell epitope regions that are highly conserved between CCHFV strains. Altogether, our results suggest that a predominantly Th1-type immune response provides the most efficient protective immunity against CCHFV challenge. However, we cannot exclude the importance of the neutralizing antibodies as the surviving immunized mice exhibited substantial amounts of them. IMPORTANCE Crimean-Congo hemorrhagic fever virus (CCHFV) is responsible for hemorrhagic diseases in humans, with a high mortality rate. There is no FDA-approved vaccine, and there are still gaps in our knowledge of the immune responses to infection. The recently developed mouse models mimic human CCHF disease and are useful to study the immunogenicity and the protection by vaccine candidates. Our study shows that mice vaccinated with a specific DNA vaccine were fully protected. Importantly, we show that neutralizing antibodies are not sufficient for protection against CCHFV challenge but that an extra Th1-specific cellular response is required. Moreover, we describe the identification of five conserved B-cell epitopes, of which only one was previously known, that could be of great importance for the development of diagnostics tools and the improvement of vaccine candidates.

Protective efficacy of neutralizing antibodies against Ebola virus infection

Vaccine ◽  
2007 ◽  
Vol 25 (6) ◽  
pp. 993-999 ◽  
Author(s):  
Ayato Takada ◽  
Hideki Ebihara ◽  
Steven Jones ◽  
Heinz Feldmann ◽  
Yoshihiro Kawaoka
Keyword(s):  
Virus Infection ◽  
Neutralizing Antibodies ◽  
Ebola Virus ◽  
Protective Efficacy ◽  
Ebola Virus Infection

scholarly journals Identification of Surrogates and Correlates of Protection in Protective Immunity againstMycobacterium bovisInfection Induced in Neonatal Calves by Vaccination withM. bovisBCG Pasteur andM. bovisBCG Danish

2011 ◽  
Vol 18 (3) ◽  
pp. 373-379 ◽  
Author(s):  
J. C. Hope ◽  
M. L. Thom ◽  
M. McAulay ◽  
E. Mead ◽  
H. M. Vordermeier ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Immune Responses ◽  
Protective Immunity ◽  
Protective Efficacy ◽  
Significant Degree ◽  
Degree Of Protection ◽  
Correlates Of Protection ◽  
Ifn Γ ◽  
Neonatal Calves ◽  
Protection Against Infection

ABSTRACTVaccination of neonatal calves withMycobacterium bovisbacillus Calmette-Guérin (BCG) induces a significant degree of protection against infection with virulentM. bovis, the causative agent of bovine tuberculosis (bTB). We compared two strains of BCG, Pasteur and Danish, in order to confirm that the current European human vaccine strain (BCG Danish) induced protective immunity in calves, and we assessed immune responses to determine correlates of protection that could assist future vaccine evaluation in cattle. Both vaccine strains induced antigen (purified protein derivate [PPD])-specific gamma interferon (IFN-γ) in whole-blood cultures. These responses were not significantly different for BCG Pasteur and BCG Danish and peaked at week 2 to 4 postvaccination. Vaccination with either BCG Danish or BCG Pasteur induced significant protection against bTB, with reductions in both lesion score and bacteriological burden evident in both groups of vaccinated calves compared with nonvaccinated control calves. Measurement of IFN-γ-expressing T lymphocytes postvaccination and postchallenge revealed both correlates and surrogates of protective efficacy. The frequency of central memory T lymphocytes present at 12 weeks postvaccination (at the time ofM. bovischallenge) correlated significantly with protection. Conversely, the number of IFN-γ-expressing effector T cells present afterM. bovischallenge was correlated with disease. These results demonstrate that vaccination of neonatal calves with either BCG Pasteur or BCG Danish induces protective immune responses against TB. In addition, we show that measurement of antigen-specific T lymphocyte populations may provide a reliable means for identifying protective vaccine candidates.

scholarly journals Overcoming Immunity to a Viral Vaccine by DNA Priming before Vector Boosting

2003 ◽  
Vol 77 (1) ◽  
pp. 799-803 ◽  
Author(s):  
Zhi-yong Yang ◽  
Linda S. Wyatt ◽  
Wing-pui Kong ◽  
Zoe Moodie ◽  
Bernard Moss ◽  
...  
Keyword(s):  
Immune Responses ◽  
Viral Vectors ◽  
Ebola Virus ◽  
Viral Vector ◽  
Hemorrhagic Fever ◽  
Viral Immunity ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Viral Vaccine ◽  
Humoral Responses

ABSTRACT Replication-defective adenovirus (ADV) and poxvirus vectors have shown potential as vaccines for pathogens such as Ebola or human immunodeficiency virus in nonhuman primates, but prior immunity to the viral vector in humans may limit their clinical efficacy. To overcome this limitation, the effect of prior viral exposure on immune responses to Ebola virus glycoprotein (GP), shown previously to protect against lethal hemorrhagic fever in animals, was studied. Prior exposure to ADV substantially reduced the cellular and humoral immune responses to GP expressed by ADV, while exposure to vaccinia inhibited vaccine-induced cellular but not humoral responses to GP expressed by vaccinia. This inhibition was largely overcome by priming with a DNA expression vector before boosting with the viral vector. Though heterologous viral vectors for priming and boosting can also overcome this effect, the paucity of such clinical viral vectors may limit their use. In summary, it is possible to counteract prior viral immunity by priming with a nonviral, DNA vaccine.

scholarly journals Protective Efficacy and Long-Term Immunogenicity in Cynomolgus Macaques by Ebola Virus Glycoprotein Synthetic DNA Vaccines

2018 ◽  
Vol 219 (4) ◽  
pp. 544-555 ◽  
Author(s):  
Ami Patel ◽  
Emma L Reuschel ◽  
Kimberly A Kraynyak ◽  
Trina Racine ◽  
Daniel H Park ◽  
...  
Keyword(s):  
Immune Responses ◽  
Ebola Virus ◽  
Dna Vaccines ◽  
Viral Vector ◽  
Protective Efficacy ◽  
Lethal Challenge ◽  
Virus Glycoprotein ◽  
Cynomolgus Macaques ◽  
The Impact

Abstract Background There remains an important need for prophylactic anti-Ebola virus vaccine candidates that elicit long-lasting immune responses and can be delivered to vulnerable populations that are unable to receive live-attenuated or viral vector vaccines. Methods We designed novel synthetic anti-Ebola virus glycoprotein (EBOV-GP) DNA vaccines as a strategy to expand protective breadth against diverse EBOV strains and evaluated the impact of vaccine dosing and route of administration on protection against lethal EBOV-Makona challenge in cynomolgus macaques. Long-term immunogenicity was monitored in nonhuman primates for >1 year, followed by a 12-month boost. Results Multiple-injection regimens of the EBOV-GP DNA vaccine, delivered by intramuscular administration followed by electroporation, were 100% protective against lethal EBOV-Makona challenge. Impressively, 2 injections of a simple, more tolerable, and dose-sparing intradermal administration followed by electroporation generated strong immunogenicity and was 100% protective against lethal challenge. In parallel, we observed that EBOV-GP DNA vaccination induced long-term immune responses in macaques that were detectable for at least 1 year after final vaccination and generated a strong recall response after the final boost. Conclusions These data support that this simple intradermal-administered, serology-independent approach is likely important for additional study towards the goal of induction of anti-EBOV immunity in multiple at-risk populations.

scholarly journals GP38-targeting monoclonal antibodies protect adult mice against lethal Crimean-Congo hemorrhagic fever virus infection

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw9535 ◽  
Author(s):  
Joseph W. Golden ◽  
Charles J. Shoemaker ◽  
Michael E. Lindquist ◽  
Xiankun Zeng ◽  
Sharon P. Daye ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Neutralizing Antibodies ◽  
Protective Efficacy ◽  
Hemorrhagic Fever ◽  
Fever Virus ◽  
Type I ◽  
Crimean Congo Hemorrhagic Fever ◽  
Hemorrhagic Fever Virus ◽  
Adult Mice ◽  
Virus Exposure

Crimean-Congo hemorrhagic fever virus (CCHFV) is an important human pathogen. Limited evidence suggests that antibodies can protect humans against lethal CCHFV disease but the protective efficacy of antibodies has never been evaluated in adult animal models. Here, we used adult mice to investigate the protection provided against CCHFV infection by glycoprotein-targeting neutralizing and non-neutralizing monoclonal antibodies (mAbs). We identified a single non-neutralizing antibody (mAb-13G8) that protected adult type I interferon–deficient mice >90% when treatment was initiated before virus exposure and >60% when administered after virus exposure. Neutralizing antibodies known to protect neonatal mice from lethal CCHFV infection failed to confer protection regardless of immunoglobulin G subclass. The target of mAb-13G8 was identified as GP38, one of multiple proteolytically cleaved glycoproteins derived from the CCHFV glycoprotein precursor polyprotein. This study reveals GP38 as an important antibody target for limiting CCHFV pathogenesis and lays the foundation to develop immunotherapeutics against CCHFV in humans.

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