Current ebola vaccines

Broad antibody and T cell responses to Ebola, Sudan, and Bundibugyo ebolaviruses using mono- and multi-valent adjuvanted glycoprotein vaccines

Currently, there are two approved vaccine regimens designed to prevent Ebola virus (EBOV) disease (EVD). Both are virus-vectored, and concerns about cold-chain storage and pre-existing immunity to the vectors warrant investigating additional vaccine strategies. Here, we have explored the utility of adjuvanted recombinant glycoproteins (GPs) from ebolaviruses Zaire (EBOV), Sudan (SUDV), and Bundibugyo (BDBV) for inducing antibody (Ab) and T cell cross-reactivity. Glycoproteins expressed in insect cells were administered to C57BL/6 mice as free protein or bound to the surface of liposomes, and formulated with toll-like receptor agonists CpG and MPLA (agonists for TLR 9 and 4, respectively), with or without the emulsions AddaVax or TiterMax. The magnitude of Ab cross-reactivity in binding and neutralization assays, and T cell cross-reactivity in antigen recall assays, correlated with phylogenetic relatedness. While most adjuvants screened induced IgG responses, a combination of CpG, MPLA and AddaVax emulsion ("IVAX-1") was the most potent and polarized in an IgG2c (Th1) direction. Breadth was also achieved by combining GPs into a trivalent (Tri-GP) cocktail with IVAX-1, which did not compromise antibody responses to individual components in binding and neutralizing assays. Th1 signature cytokines in T cell recall assays were undetectable after Tri-GP/IVAX-1 administration, despite a robust IgG2c response, although administration of Tri-GP on lipid nanoparticles in IVAX-1 elevated Th1 cytokines to detectable levels. Overall, the data indicate an adjuvanted trivalent recombinant GP approach may represent a path toward a broadly reactive, deployable vaccine against EVD.

Recent Advances in Therapeutic Approaches Against Ebola Virus Infection

BACKGROUND

Ebola virus (EBOV) is a genus of negative-strand RNA viruses belonging to the family Filoviradae that was first described in 1976 in the present-day Democratic Republic of the Congo. It has intermittently affected substantial human populations in West Africa and presents itself as a global health menace due to the high mortality rate of patients, high transmission rate, difficult patient management, and the emergence of complicated autoimmune disease-like conditions post-infection.

OBJECTIVE

EBOV or other EBOV-like species as a biochemical weapon pose a significant risk; hence, the need to develop both prophylactic and therapeutic medications to combat the virus is unquestionable.

METHODS

In this review work, we have compiled the literature pertaining to transmission, pathogenesis, immune response, and diagnosis of EBOV infection. We included detailed structural details of EBOV along with all the available therapeutics against EBOV disease. We have also highlighted current developments and recent advances in therapeutic approaches against Ebola virus disease (EVD).

DISCUSSION

The development of preventive vaccines against the virus is proving to be a successful effort as of now; however, problems concerning logistics, product stability, multi- dosing, and patient tracking are prominent in West Africa. Monoclonal antibodies that target EBOV proteins have also been developed and approved in the clinic; however, no small drug molecules that target these viral proteins have cleared clinical trials. An understanding of clinically approved vaccines and their shortcomings also serves an important purpose for researchers in vaccine design in choosing the right vector, antigen, and particular physicochemical properties that are critical for the vaccine's success against the virus across the world.

CONCLUSION

Our work brings together a comprehensive review of all available prophylactic and therapeutic medications developed and under development against the EBOV, which will serve as a guide for researchers in pursuing the most promising drug discovery strategies against the EBOV and also explore novel mechanisms of fighting against EBOV infection.

Effects of adjuvants in a rabies-vectored Ebola virus vaccine on protection from surrogate challenge

Ebola virus is the primary contributor to the global threat of filovirus severe hemorrhagic fever, and Ebola virus disease has a case fatality rate of 50-90%. An inactivated, bivalent filovirus/rabies virus vaccine, FILORAB1, consists of recombinant rabies virus virions expressing the Ebola virus glycoprotein. FILORAB1 is immunogenic and protective from Ebola virus challenge in mice and non-human primates, and protection is enhanced when formulated with toll-like receptor 4 agonist Glucopyranosyl lipid adjuvant (GLA) in a squalene oil-in-water emulsion (SE). Through an adjuvant comparison in mice, we demonstrate that GLA-SE improves FILORAB1 efficacy by activating the innate immune system and shaping a Th1-biased adaptive immune response. GLA-SE adjuvanted mice and those adjuvanted with the SE component are better protected from surrogate challenge, while Th2 alum adjuvanted mice are not. Additionally, the immune response to FILORAB1 is long-lasting, as exhibited by highly-maintained serum antibody titers and long-lived cells in the spleen and bone marrow.

Single-step rapid chromatographic purification and characterization of clinical stage oncolytic VSV-GP

Purification of viruses, especially for therapeutic purposes, is a tedious and challenging task. The challenges arise due to the size and surface complexity of the virus particles. VSV-GP is a promising oncolytic virus, which has been approved for phase I clinical trials by the Food and Drug Administration (FDA) of United States and Paul Ehrlich Institute (PEI) of Germany. The virus particles of VSV-GP are larger in size than vectors commonly used for gene therapy (e.g., adenovirus, adeno-associated virus, etc.). The current established proprietary clinical-grade manufacturing process for the purification of VSV-GP encompasses several chromatographic and non-chromatographic steps. In this study, we describe a new single-step purification process for the purification of VSV-GP virus, using cation exchange convective flow column with relatively higher yields. The purified virus was characterized for its quality attributes using TCID50 assay (for viral infectivity), host cell protein contaminant ELISA, SDS-PAGE, size exclusion chromatography (SEC), and cryo-electron microscopy. Furthermore, the purified viral therapeutic material was tested in vivo for its efficacy and safety. All these characterization methods demonstrated a therapeutic virus preparation of high purity and yield, which can be readily used for various studies.

A Historical Review of Military Medical Strategies for Fighting Infectious Diseases: From Battlefields to Global Health

The environmental conditions generated by war and characterized by poverty, undernutrition, stress, difficult access to safe water and food as well as lack of environmental and personal hygiene favor the spread of many infectious diseases. Epidemic typhus, plague, malaria, cholera, typhoid fever, hepatitis, tetanus, and smallpox have nearly constantly accompanied wars, frequently deeply conditioning the outcome of battles/wars more than weapons and military strategy. At the end of the nineteenth century, with the birth of bacteriology, military medical researchers in Germany, the United Kingdom, and France were active in discovering the etiological agents of some diseases and in developing preventive vaccines. Emil von Behring, Ronald Ross and Charles Laveran, who were or served as military physicians, won the first, the second, and the seventh Nobel Prize for Physiology or Medicine for discovering passive anti-diphtheria/tetanus immunotherapy and for identifying mosquito Anopheline as a malaria vector and plasmodium as its etiological agent, respectively. Meanwhile, Major Walter Reed in the United States of America discovered the mosquito vector of yellow fever, thus paving the way for its prevention by vector control. In this work, the military relevance of some vaccine-preventable and non-vaccine-preventable infectious diseases, as well as of biological weapons, and the military contributions to their control will be described. Currently, the civil-military medical collaboration is getting closer and becoming interdependent, from research and development for the prevention of infectious diseases to disasters and emergencies management, as recently demonstrated in Ebola and Zika outbreaks and the COVID-19 pandemic, even with the high biocontainment aeromedical evacuation, in a sort of global health diplomacy.

Recent developments and strategies of Ebola virus vaccines

The Filovirus family member, Ebola virus (EBOV), is a highly infectious pathogen responsible for viral hemorrhagic fever. EBOV has a fatality rate in the range 50%-90% in primates. The lethal viral hemorrhagic attack in 2014 by EBOV has forced the human race to look for rapid countermeasures. Fortunately, owing to continuous efforts and several vaccine platforms, few potential vaccine candidates are emerging, such as replicative and non-replicative vectored vaccines, polyepitopic or monovalent vaccines, and DNA vaccines. This article reviewed various kinds of EBOV vaccines in different clinical trial phases and their approval status. Updated knowledge of vaccine development progress might stimulate the researchers to look for more potent and effective vaccine candidates against EBOV.

Vaccines against Ebola virus and Marburg virus: recent advances and promising candidates

The filoviruses Ebola virus and Marburg virus are among the most dangerous pathogens in the world. Both viruses cause viral hemorrhagic fever, with case fatality rates of up to 90%. Historically, filovirus outbreaks had been relatively small, with only a few hundred cases reported. However, the recent West African Ebola virus outbreak underscored the threat that filoviruses pose. The three year-long outbreak resulted in 28,646 Ebola virus infections and 11,323 deaths. The lack of Food and Drug Administration (FDA) licensed vaccines and antiviral drugs hindered early efforts to contain the outbreak. In response, the global scientific community has spurred the advanced development of many filovirus vaccine candidates. Novel vaccine platforms, such as viral vectors and DNA vaccines, have emerged, leading to the investigation of candidate vaccines that have demonstrated protective efficacy in small animal and nonhuman primate studies. Here, we will discuss several of these vaccine platforms with a particular focus on approaches that have advanced into clinical development.

Effects of vaccines in protecting against Ebola virus disease: protocol for a systematic review

INTRODUCTION

Ebola virus disease is one of the most devastating infectious diseases in the world with up to 90% case fatality observed. There are at least 13 candidate vaccines developed and being tested to prevent the occurrence of the Ebola virus disease. While none of these candidate vaccines has received regulatory approval for use, one candidate vaccine (rVSVΔG-ZEBOV-GP) has been granted access for emergency use. Two other candidate vaccines (GamEvac-Combi and Ad5-EBOV) have been licensed for emergency use in their countries of origin. The objective of this systematic review is to summarise the effects of the Ebola candidate vaccines in humans.

METHODS AND ANALYSIS

We will search for potentially eligible studies, with no language or date restrictions, in the Cochrane Central Register of Controlled Trials, PubMed, Scopus, the WHO International Clinical Trial Registry Platform, and reference lists of relevant publications. The Cochrane Database of Systematic Reviews (CDSR) and the Database of Abstracts of Reviews of Effect (DARE) will be searched for related reviews. Two review authors will independently screen search records, assess study eligibility, perform data extraction, and assess the risk of bias; and reconcile their findings. We will pool data from similar studies using Mantel-Haenszel's fixed-effect model.

ETHICS AND DISSEMINATION

This study is exempted from ethical consideration since the data collected are publicly available and at no point will confidential information from human participants be used. We will disseminate our results through publications in peer-reviewed journals and relevant conferences.

PROSPERO REGISTRATION NUMBER

CRD42018110505.

Metal-Organic Frameworks for Cell and Virus Biology: A Perspective

Metal-organic frameworks (MOFs) are a class of coordination polymers, consisting of metal ions or clusters linked together by chemically mutable organic groups. In contrast to zeolites and porous carbons, MOFs are constructed from a building block strategy that enables molecular level control of pore size/shape and functionality. An area of growing interest in MOF chemistry is the synthesis of MOF-based composite materials. Recent studies have shown that MOFs can be combined with biomacromolecules to generate novel biocomposites. In such materials, the MOF acts as a porous matrix that can encapsulate enzymes, oligonucleotides, or even more complex structures that are capable of replication/reproduction (i.e., viruses, bacteria, and eukaryotic cells). The synthetic approach for the preparation of these materials has been termed "biomimetic mineralization", as it mimics natural biomineralization processes that afford protective shells around living systems. In this Perspective, we focus on the preparation of MOF biocomposites that are composed of complex biological moieties such as viruses and cells and canvass the potential applications of this encapsulation strategy to cell biology and biotechnology.

Ebola virus - epidemiology, diagnosis, and control: threat to humans, lessons learnt, and preparedness plans - an update on its 40 year's journey

Ebola virus (EBOV) is an extremely contagious pathogen and causes lethal hemorrhagic fever disease in man and animals. The recently occurred Ebola virus disease (EVD) outbreaks in the West African countries have categorized it as an international health concern. For the virus maintenance and transmission, the non-human primates and reservoir hosts like fruit bats have played a vital role. For curbing the disease timely, we need effective therapeutics/prophylactics, however, in the absence of any approved vaccine, timely diagnosis and monitoring of EBOV remains of utmost importance. The technologically advanced vaccines like a viral-vectored vaccine, DNA vaccine and virus-like particles are underway for testing against EBOV. In the absence of any effective control measure, the adaptation of high standards of biosecurity measures, strict sanitary and hygienic practices, strengthening of surveillance and monitoring systems, imposing appropriate quarantine checks and vigilance on trade, transport, and movement of visitors from EVD endemic countries remains the answer of choice for tackling the EBOV spread. Herein, we converse with the current scenario of EBOV giving due emphasis on animal and veterinary perspectives along with advances in diagnosis and control strategies to be adopted, lessons learned from the recent outbreaks and the global preparedness plans. To retrieve the evolutionary information, we have analyzed a total of 56 genome sequences of various EBOV species submitted between 1976 and 2016 in public databases.

Vesicular Stomatitis Virus Pseudotyped with Ebola Virus Glycoprotein Serves as a Protective, Noninfectious Vaccine against Ebola Virus Challenge in Mice

The recent Ebola virus (EBOV) epidemic in West Africa demonstrates the potential for a significant public health burden caused by filoviral infections. No vaccine or antiviral is currently FDA approved. To expand the vaccine options potentially available, we assessed protection conferred by an EBOV vaccine composed of vesicular stomatitis virus pseudovirions that lack native G glycoprotein (VSVΔG) and bear EBOV glycoprotein (GP). These pseudovirions mediate a single round of infection. Both single-dose and prime/boost vaccination regimens protected mice against lethal challenge with mouse-adapted Ebola virus (ma-EBOV) in a dose-dependent manner. The prime/boost regimen provided significantly better protection than a single dose. As N-linked glycans are thought to shield conserved regions of the EBOV GP receptor-binding domain (RBD), thereby blocking epitopes within the RBD, we also tested whether VSVΔG bearing EBOV GPs that lack GP1 N-linked glycans provided effective immunity against challenge with ma-EBOV or a more distantly related virus, Sudan virus. Using a prime/boost strategy, high doses of GP/VSVΔG partially or fully denuded of N-linked glycans on GP1 protected mice against ma-EBOV challenge, but these mutants were no more effective than wild-type (WT) GP/VSVΔG and did not provide cross protection against Sudan virus. As reported for other EBOV vaccine platforms, the protection conferred correlated with the quantity of EBOV GP-specific Ig produced but not with the production of neutralizing antibodies. Our results show that EBOV GP/VSVΔG pseudovirions serve as a successful vaccination platform in a rodent model of Ebola virus disease and that GP1 N-glycan loss does not influence immunogenicity or vaccination success.IMPORTANCE The West African Ebola virus epidemic was the largest to date, with more than 28,000 people infected. No FDA-approved vaccines are yet available, but in a trial vaccination strategy in West Africa, recombinant, infectious VSV encoding the Ebola virus glycoprotein effectively prevented virus-associated disease. VSVΔG pseudovirion vaccines may prove as efficacious and have better safety, but they have not been tested to date. Thus, we tested the efficacy of VSVΔG pseudovirions bearing Ebola virus glycoprotein as a vaccine platform. We found that wild-type Ebola virus glycoprotein, in the context of this platform, provides robust protection of EBOV-challenged mice. Further, we found that removal of the heavy glycan shield surrounding conserved regions of the glycoprotein does not enhance vaccine efficacy.

Ebola virus - from neglected threat to global emergency state

OBJECTIVE

This review aims to update knowledge about Ebola virus disease (EVD) and recent advances in its diagnosis, treatment and prevention.

METHOD

A literature review was performed using the following databases: ISI Web of Knowledge, PubMed, IRIS, Scopus and the websites of the CDC and the WHO. Additionally, we have included articles and reports referenced in the basic literature search, and news that were considered relevant.

RESULTS

The Ebola virus, endemic in some parts of Africa, is responsible for a severe form of hemorrhagic fever in humans; bats are probably its natural reservoir. It is an extremely virulent virus and easily transmitted by bodily fluids. EVD's complex pathophysiology, characterized by immunosuppression as well as stimulation of an intense inflammatory response, results in a syndrome similar to septic shock. The diagnosis is difficult due to the initial symptoms that mimic other diseases. Despite the high mortality rates that can amount to 90%, a prophylaxis (chemical or vaccine) or effective treatment does not exist. Two vaccines and experimental therapies are being developed for the prevention and treatment of EVD.

CONCLUSION

Although the virus is known for about 40 years, the lack of knowledge obtained and the disinterest of government authorities in the countries involved justify the state of emergency currently exists regarding this infectious agent. Only the coordination of multiple entities and the effective commitment of the international community will facilitate the control and effective prevention of EVD.

A Perspective on the Development of Plant-Made Vaccines in the Fight against Ebola Virus

The Ebola virus (EBOV) epidemic indicated a great need for prophylactic and therapeutic strategies. The use of plants for the production of biopharmaceuticals is a concept being adopted by the pharmaceutical industry, with an enzyme for human use currently commercialized since 2012 and some plant-based vaccines close to being commercialized. Although plant-based antibodies against EBOV are under clinical evaluation, the development of plant-based vaccines against EBOV essentially remains an unexplored area. The current technologies for the production of plant-based vaccines include stable nuclear expression, transient expression mediated by viral vectors, and chloroplast expression. Specific perspectives on how these technologies can be applied for developing anti-EBOV vaccines are provided, including possibilities for the design of immunogens as well as the potential of the distinct expression modalities to produce the most relevant EBOV antigens in plants considering yields, posttranslational modifications, production time, and downstream processing.

Expression of an immunogenic LTB-based chimeric protein targeting Zaire ebolavirus epitopes from GP1 in plant cells

KEY MESSAGE

An antigenic protein targeting two epitopes from the Zaire ebolavirus GP1 protein was expressed in plant cells rendering an antigen capable of inducing humoral responses in mouse when administered subcutaneously or orally. The 2014 Ebola outbreak made clear that new treatments and prophylactic strategies to fight this disease are needed. Since vaccination is an intervention that could achieve the control of this epidemic disease, exploring the production of new low-cost vaccines is a key path to consider; especially in developing countries. In this context, plants are attractive organisms for the synthesis and delivery of subunit vaccines. This study aimed at producing a chimeric protein named LTB-EBOV, based on the B subunit of the Escherichia coli heat-labile enterotoxin as an immunogenic carrier and two epitopes from the Zaire ebolavirus GP1 protein recognized by neutralizing antibodies. The LTB-EBOV protein was expressed in plant tissues at levels up to 14.7 µg/g fresh leaf tissue and proven to be immunogenic in BALB/c mice when administered by either subcutaneous or oral routes. Importantly, IgA and IgG responses were induced following the oral immunization. The potential use of the plant-made LTB-EBOV protein against EBOV is discussed.

Improving health care workers' protection against infection of Ebola hemorrhagic fever through video surveillance

BACKGROUND

The purpose of this study was to investigate the importance of supervision through video surveillance in improving the quality of personal protection in preparing health care workers working in Ebola treatment units.

METHODS

Wardens supervise, remind, and guide health care workers' behavior through onsite voice and video systems when they are in the suspected patient observation ward and in the patient diagnosed ward of the Ebola treatment center. The observation results were recorded, and timely feedback was given to the health care workers.

RESULTS

After 2 months of supervision, 1,797 cases of incorrect personal protection behaviors were identified and corrected. The error rate continuously declined. The declined rate of the first 2 weeks was statistically different from other time periods. Through reminding and supervising, nonstandard personal protective behaviors can be discovered and corrected, which can help health care workers standardize personal protection. The timely feedback from video surveillance can also offer psychologic support and encouragement promptly to ease psychologic pressure. Finally, this can ensure health care workers stay at a zero infection rate during patient treatment.

CONCLUSIONS

Personal protective equipment protocol supervised by wardens through a video monitoring process can be used as an effective complement to conventional mutual supervision methods and can help health care workers avoid Ebola infection during treatment.

Cell culture-based viral vaccines: current status and future prospects

Cell culture-based viral vaccines are used globally to immunize humans against infections. The cell culture is continuous process of developing substrates for the safe production of viral vaccines. However, increased global demand and strict safety rules for novel vaccines to control and eradicate viral diseases have forced researchers and manufacturers toward cell culture-based vaccines. The choice of cell substrate is a critical step that cannot be generalized for every vaccine formulation, therefore, manufacturers intend to optimize the required processes for particular applications. The recently established cell lines, innovative bioreactor concepts and cultivation schemes are necessary to increase the potential of vaccine production. In this review, we have focused on current cell culture-based viral vaccines and their future prospects.

Knowledge and attitude regarding Ebola virus disease among medical students of Rawalpindi: A preventable threat not yet confronted

OBJECTIVE

To assess the knowledge and attitude regarding Ebola virus disease (EVD) among medical students of Rawalpindi.

METHODS

A descriptive cross sectional study was carried out in a medical college of Rawalpindi from September 2014-November 2014. About 400 students were inducted with 77% (n=308) response rate. After taking informed verbal consent from students and administration, a pre-designed and pre-tested questionnaire was circulated among students of third, fourth and final year MBBS as well as third and fourth year BDS. The data collected was entered and analyzed using SPSS 20.

RESULTS

The response rate was 77% (308/400). About 244 (79.2%) of students had heard about EVD before. One hundred and sixty four (53.2%) of the students correctly identified that no treatment is available for EVD as yet. Also 163 (52.9%) said that no vaccine was available against the virus either. Washing hands every time after touching a patient in clinics/wards was important for 151 (49.0%) while 223 (72.4%) claimed to use proper techniques to dispose off used injections.

CONCLUSION

Students have basic knowledge regarding EVD. However, there is deficient information regarding the diagnosis and precautionary measures required to control it.

Preparing for Serious Communicable Diseases in the United States: What the Ebola Virus Epidemic Has Taught Us

Ending the West Africa Ebola virus disease (EVD) outbreak required an unprecedented international response. For the United States, participation in the international response to the West Africa EVD outbreak provided an opportunity to learn important lessons in four key domains critical to preparing for future outbreaks of EVD and other serious communicable diseases: (i) safe and effective patient care, (ii) the role of experimental therapeutics and vaccines, (iii) infection control, and (iv) hospital and community preparedness.

Therapeutic potential of the heme oxygenase-1 inducer hemin against Ebola virus infection

Promising drugs to treat Ebola virus (EBOV) infection are currently being developed, but so far none has shown efficacy in clinical trials. Drugs that can stimulate host innate defense responses may retard the progression of EBOV disease. We report here the dramatic effect of hemin, the natural inducer of the heme catabolic enzyme heme oxygenase-1 (HO-1), in the reduction of EBOV replication. Treatment of primary monocyte-derived macrophages (MDM), Vero E6 cells, HeLa cells, and human foreskin fibroblasts (HFF1) with hemin reduced EBOV infection by >90%, and showed minimal toxicity to infected cells. Inhibition of HO-1 enzymatic activity and silencing HO-1 expression prevented the hemin-mediated suppression of EBOV infection, suggesting an important role for induction of this intracellular mediator in restricting EBOV replication. The inverse correlation between hemin-induced HO-1 and EBOV replication provides a potentially useful therapeutic modality based on the stimulation of an innate cellular response against Ebola infection.

Retracted: Ebola virus: an introduction and its pathology

The Ebola viruses are causative agent of a severe Ebola virus disease (EVD) or Ebola hemorrhagic fever (EHF) in human and other primates. Transmission of EVD occurs through the contact of body fluids from infected persons or animals, making it one of the most epidemic diseases worldwide. Underestimating the Ebola virus has cost loss of precious human lives in recent years. Ebola virus outbreak in year 2014 created a history, affecting a larger population in a wide geographical region of African sub-continent. EVD outbreaks have a case fatality rate of up to 70%. Ebola viruses are endemic in regions of Africa. Ebola viruses mainly target the hepatocytes, endothelial, and macrophage-rich lymphoid tissues and are characterized by immune suppression and a systemic inflammatory response that causes impairment of the vascular, coagulation, and immune systems. This impairment leads to multifocal necrosis and multi organ failure, and thus, in some ways, resembling septic shock. Currently, neither a specific treatment nor a vaccine licensed for use in humans is available. This review is focused on general characteristic of Ebola viruses, its pathogenesis, immunological response of host, and recent approaches for vaccine development against EVD. Copyright © 2015 John Wiley & Sons, Ltd.

Future Challenges for Vaccinologists

Vaccination is one of the cheapest health-care interventions that have saved more lives than any other drugs or therapies. Due to successful immunization programs we rarely hear about some of the common diseases of the early twentieth century including small pox and polio. Vaccination programs have also helped to increase food production notably poultry, cattle, and milk production due to lower incidence of infectious diseases in farm animals. Though vaccination programs have eradicated several diseases and increased the quality of life there are several diseases that have no effective vaccines. Currently there are no vaccines for cancer, neurodegenerative diseases, autoimmune diseases, as well as infectious diseases like tuberculosis, AIDS, and parasitic diseases including malaria. Abuse of antibiotics has resulted in the generation of several antibiotic-resistant bacterial strains; hence there is a need to develop novel vaccines for antibiotic-resistant microorganisms. Changes in climate is another concern for vaccinologists. Climate change could lead to generation of new strains of infectious microorganisms that would require development of novel vaccines. Use of conventional vaccination strategies to develop vaccines has severe limitations; hence innovative strategies are essential in the development of novel and effective vaccines.

Virion-associated phosphatidylethanolamine promotes TIM1-mediated infection by Ebola, dengue, and West Nile viruses

Phosphatidylserine (PS) receptors contribute to two crucial biological processes: apoptotic clearance and entry of many enveloped viruses. In both cases, they recognize PS exposed on the plasma membrane. Here we demonstrate that phosphatidylethanolamine (PE) is also a ligand for PS receptors and that this phospholipid mediates phagocytosis and viral entry. We show that a subset of PS receptors, including T-cell immunoglobulin (Ig) mucin domain protein 1 (TIM1), efficiently bind PE. We further show that PE is present in the virions of flaviviruses and filoviruses, and that the PE-specific cyclic peptide lantibiotic agent Duramycin efficiently inhibits the entry of West Nile, dengue, and Ebola viruses. The inhibitory effect of Duramycin is specific: it inhibits TIM1-mediated, but not L-SIGN-mediated, virus infection, and it does so by blocking virus attachment to TIM1. We further demonstrate that PE is exposed on the surface of apoptotic cells, and promotes their phagocytic uptake by TIM1-expressing cells. Together, our data show that PE plays a key role in TIM1-mediated virus entry, suggest that disrupting PE association with PS receptors is a promising broad-spectrum antiviral strategy, and deepen our understanding of the process by which apoptotic cells are cleared.

Recent advances in the development of vaccines for Ebola virus disease

Ebola virus is one of the most dangerous microorganisms in the world causing hemorrhagic fevers in humans and non-human primates. Ebola virus (EBOV) is a zoonotic infection, which emerges and re-emerges in human populations. The 2014 outbreak was caused by the Zaire strain, which has a kill rate of up to 90%, though 40% was recorded in the current outbreak. The 2014 outbreak is larger than all 20 outbreaks that have occurred since 1976, when the virus was first discovered. It is the first time that the virus was sustained in urban centers and spread beyond Africa into Europe and USA. Thus far, over 22,000 cases have been reported with about 50% mortality in one year. There are currently no approved therapeutics and preventive vaccines against Ebola virus disease (EVD). Responding to the devastating effe1cts of the 2014 outbreak and the potential risk of global spread, has spurred research for the development of therapeutics and vaccines. This review is therefore aimed at presenting the progress of vaccine development. Results showed that conventional inactivated vaccines produced from EBOV by heat, formalin or gamma irradiation appear to be ineffective. However, novel vaccines production techniques have emerged leading to the production of candidate vaccines that have been demonstrated to be effective in preclinical trials using small animal and non-human primates (NHP) models. Some of the promising vaccines have undergone phase 1 clinical trials, which demonstrated their safety and immunogenicity. Many of the candidate vaccines are vector based such as Vesicular Stomatitis Virus (VSV), Rabies Virus (RABV), Adenovirus (Ad), Modified Vaccinia Ankara (MVA), Cytomegalovirus (CMV), human parainfluenza virus type 3 (HPIV3) and Venezuelan Equine Encephalitis Virus (VEEV). Other platforms include virus like particle (VLP), DNA and subunit vaccines.

Formulation and stabilization of recombinant protein based virus-like particle vaccines

Vaccine formulation development has traditionally focused on improving antigen storage stability and compatibility with conventional adjuvants. More recently, it has also provided an opportunity to modify the interaction and presentation of an antigen/adjuvant to the immune system to better stimulate the desired immune responses for maximal efficacy. In the last decade, there has been a paradigm shift in vaccine antigen and formulation design involving an improved physical understanding of antigens and a better understanding of the immune system. In addition, the discovery of novel adjuvants and delivery systems promises to further improve the design of new, more effective vaccines. Here we describe some of the fundamental aspects of formulation design applicable to virus-like-particle based vaccine antigens (VLPs). Case studies are presented for commercially approved VLP vaccines as well as some investigational VLP vaccine candidates. An emphasis is placed on the biophysical analysis of vaccines to facilitate formulation and stabilization of these particulate antigens.

Epitope-based peptide vaccine design and target site depiction against Ebola viruses: an immunoinformatics study

Ebola viruses (EBOVs) have been identified as an emerging threat in recent year as it causes severe haemorrhagic fever in human. Epitope‐based vaccine design for EBOVs remains a top priority because a mere progress has been made in this regard. Another reason is the lack of antiviral drug and licensed vaccine although there is a severe outbreak in Central Africa. In this study, we aimed to design an epitope‐based vaccine that can trigger a significant immune response as well as to prognosticate inhibitor that can bind with potential drug target sites using various immunoinformatics and docking simulation tools. The capacity to induce both humoral and cell‐mediated immunity by T cell and B cell was checked for the selected protein. The peptide region spanning 9 amino acids from 42 to 50 and the sequence TLASIGTAF were found as the most potential B and T cell epitopes, respectively. This peptide could interact with 12 HLAs and showed high population coverage up to 80.99%. Using molecular docking, the epitope was further appraised for binding against HLA molecules to verify the binding cleft interaction. In addition with this, the allergenicity of the epitopes was also evaluated. In the post‐therapeutic strategy, docking study of predicted 3D structure identified suitable therapeutic inhibitor against targeted protein. However, this computational epitope‐based peptide vaccine designing and target site prediction against EBOVs open up a new horizon which may be the prospective way in Ebola viruses research; the results require validation by in vitro and in vivo experiments.

Highly conserved regions in Ebola virus RNA dependent RNA polymerase may be act as a universal novel peptide vaccine target: a computational approach

Purpose

Ebola virus (EBOV) is such kind of virus which is responsible for 23,825 cases and 9675 deaths worldwide only in 2014 and with an average diseases fatality rate between 25 % and 90 %. Although, medical technology has tried to handle the problems, there is no Food and Drug Administration (FDA)-approved therapeutics or vaccines available for the prevention, post exposure, or treatment of Ebola virus disease (EVD).

Methods

In the present study, we used the immunoinformatics approach to design a potential epitope-based vaccine against the RNA-dependent RNA polymerase-L of EBOV. BioEdit v7.2.3 sequence alignment editor, Jalview v2 and CLC Sequence Viewer v7.0.2 were used for the initial sequence analysis for securing the conservancy from the sequences. Later the Immune Epitope Database and Analysis Resource (IEDB-AR) was used for the identification of T-cell and B-cellepitopes associated with type I and II major histocompatibility complex molecules analysis. Finally, the population coverage analysis was employed.

Results

The core epitope “FRYEFTAPF” was found to be the most potential one, with 100 % conservancy among all the strains of EBOV. It also interacted with both type I and II major histocompatibility complex molecules and is considered as nonallergenic in nature. Finally, with impressive cumulative population coverage of 99.87 % for the both MHC-I and MHC-II class throughout the world population was found for the proposed epitope.

Conclusion

To end, the projected peptide gave us a solid stand to propose for vaccine consideration and that might be experimented for its potency in eliciting immunity through humoral and cell mediated immune responses in vitro and in vivo.

Electronic supplementary material

The online version of this article (doi:10.1186/s40203-015-0011-4) contains supplementary material, which is available to authorized users.

Development of Small-Molecule Antivirals for Ebola

Ebola hemorrhagic fever is a deadly disease caused by infection with one of the Ebola virus species. Although a significant progress has recently been made in understanding of Ebola virus biology and pathogenesis, development of effective anti-Ebola treatments has not been very productive, compared to other areas of antiviral research (e.g., HIV and HCV infections). No approved vaccine or medicine is available for Ebola but several are currently under development. This review summarises attempts in identification, evaluation, and development of small-molecule candidates for treatment of Ebola viral disease, including the most promising experimental drugs brincidofovir (CMX001), BCX4430, and favipiravir (T-705).

Ebola: a review for emergency providers

Filoviruses, including Ebola virus, are associated with outbreaks of severe febrile illness with high fatality rates in humans. The 2014 outbreak of Ebola virus in West Africa is by far the largest outbreak in history and the first to spread to highly populated urban areas. The potential for such an epidemic to spread beyond Africa through international travel has raised concern in the world community as well as in American and international health agencies. This article presents background information, personal and public protective strategies, and treatment recommendations for emergency physicians.

Against the clock towards new Ebola virus therapies

Since the end of 2013, West Africa has been suffering the largest Ebola virus (EBOV) outbreak in recorded history. The lack of health care infrastructure in the affected countries, as well as a concentration of infected cases in the most populated areas allowed the virus to spread with no control during the first months of the outbreak. With no specific treatment available to combat EBOV infection and its associated disease, an extraordinary worldwide effort was made to confront the severity of the situation and to establish new therapeutic strategies that would lead to better and faster control and eradicate the outbreak. In the last two years, several candidate therapies and potential vaccines against EBOV have arisen and human clinical trials are ongoing, in hopes of starting their deployment in the affected countries. This article reviews the current candidate therapies against EBOV, their stage of development and future prospects in battling EBOV outbreaks.

Harnessing case isolation and ring vaccination to control Ebola

As a devastating Ebola outbreak in West Africa continues, non-pharmaceutical control measures including contact tracing, quarantine, and case isolation are being implemented. In addition, public health agencies are scaling up efforts to test and deploy candidate vaccines. Given the experimental nature and limited initial supplies of vaccines, a mass vaccination campaign might not be feasible. However, ring vaccination of likely case contacts could provide an effective alternative in distributing the vaccine. To evaluate ring vaccination as a strategy for eliminating Ebola, we developed a pair approximation model of Ebola transmission, parameterized by confirmed incidence data from June 2014 to January 2015 in Liberia and Sierra Leone. Our results suggest that if a combined intervention of case isolation and ring vaccination had been initiated in the early fall of 2014, up to an additional 126 cases in Liberia and 560 cases in Sierra Leone could have been averted beyond case isolation alone. The marginal benefit of ring vaccination is predicted to be greatest in settings where there are more contacts per individual, greater clustering among individuals, when contact tracing has low efficacy or vaccination confers post-exposure protection. In such settings, ring vaccination can avert up to an additional 8% of Ebola cases. Accordingly, ring vaccination is predicted to offer a moderately beneficial supplement to ongoing non-pharmaceutical Ebola control efforts.

Ebolavirus and Haemorrhagic Syndrome

The Ebola virus is a highly virulent, single-stranded ribonucleic acid virus which affects both humans and apes and has fast become one of the world's most feared pathogens. The virus induces acute fever and death, with haemorrhagic syndrome occurring in up to 90% of patients. The known species within the genus Ebolavirus are Bundibugyo, Sudan, Zaïre, Reston and Taï Forest. Although endemic in Africa, Ebola has caused worldwide anxiety due to media hype and concerns about its international spread, including through bioterrorism. The high fatality rate is attributed to unavailability of a standard treatment regimen or vaccine. The disease is frightening since it is characterised by rapid immune suppression and systemic inflammatory response, causing multi-organ and system failure, shock and often death. Currently, disease management is largely supportive, with containment efforts geared towards mitigating the spread of the virus. This review describes the classification, morphology, infective process, natural ecology, transmission, epidemic patterns, diagnosis, clinical features and immunology of Ebola, including management and epidemic containment strategies.

Virus-like particles activate type I interferon pathways to facilitate post-exposure protection against Ebola virus infection

Ebola virus (EBOV) causes a severe hemorrhagic disease with high fatality. Virus-like particles (VLPs) are a promising vaccine candidate against EBOV. We recently showed that VLPs protect mice from lethal EBOV infection when given before or after viral infection. To elucidate pathways through which VLPs confer post-exposure protection, we investigated the role of type I interferon (IFN) signaling. We found that VLPs lead to accelerated induction of IFN stimulated genes (ISGs) in liver and spleen of wild type mice, but not in Ifnar^-/- mice. Accordingly, EBOV infected Ifnar^-/- mice, unlike wild type mice succumbed to death even after VLP treatment. The ISGs induced in wild type mice included anti-viral proteins and negative feedback factors known to restrict viral replication and excessive inflammatory responses. Importantly, proinflammatory cytokine/chemokine expression was much higher in WT mice without VLPs than mice treated with VLPs. In EBOV infected Ifnar^-/- mice, however, uninhibited viral replication and elevated proinflammatory factor expression ensued, irrespective of VLP treatment, supporting the view that type I IFN signaling helps to limit viral replication and attenuate inflammatory responses. Further analyses showed that VLP protection requires the transcription factor, IRF8 known to amplify type I IFN signaling in dendritic cells and macrophages, the probable sites of initial EBOV infection. Together, this study indicates that VLPs afford post-exposure protection by promoting expeditious initiation of type I IFN signaling in the host.

Progress of vaccine and drug development for Ebola preparedness

Since the first case of Ebola virus disease (EVD) in Guinea was reported in March 2014 by World Health Organization (WHO), the outbreak has continued through the year and the total number of 19,065 patients was reported as the confirmed or suspected in the EVD-affected countries. Among the cases, 7,388 patients were reported death by 19 December. Currently, available therapeutics to treat the infected patients or vaccines to prevent people from infection is not developed yet while viral diagnostic methods were already developed and firmly established in a lot of countries as a first step for the preparedness of Ebola outbreak. Some potential therapeutic materials including ZMapp were supplied and the treated people got over the EVD. Several candidates of vaccines also were investigated their efficacy in animal models by National Institute of Health (NIH) and Department of Defense, and they are processing of clinical tests in West Africa aiming to finish the development by the 2015. Vaccine and therapeutic development is essential to stop the EVD outbreak in West Africa, also to protect the world from the risk which can be generated by potential spread of Ebola virus.

Bolstering Components of the Immune Response Compromised by Prior Exposure to Adenovirus: Guided Formulation Development for a Nasal Ebola Vaccine

The severity and longevity of the current Ebola outbreak highlight the need for a fast-acting yet long-lasting vaccine for at-risk populations (medical personnel and rural villagers) where repeated prime-boost regimens are not feasible. While recombinant adenovirus (rAd)-based vaccines have conferred full protection against multiple strains of Ebola after a single immunization, their efficacy is impaired by pre-existing immunity (PEI) to adenovirus. To address this important issue, a panel of formulations was evaluated by an in vitro assay for their ability to protect rAd from neutralization. An amphiphilic polymer (F16, FW ∼39,000) significantly improved transgene expression in the presence of anti-Ad neutralizing antibodies (NAB) at concentrations of 5 times the 50% neutralizing dose (ND₅₀). In vivo performance of rAd in F16 was compared with unformulated virus, virus modified with poly(ethylene) glycol (PEG), and virus incorporated into poly(lactic-co-glycolic) acid (PLGA) polymeric beads. Histochemical analysis of lung tissue revealed that F16 promoted strong levels of transgene expression in naive mice and those that were exposed to adenovirus in the nasal cavity 28 days prior to immunization. Multiparameter flow cytometry revealed that F16 induced significantly more polyfunctional antigen-specific CD8⁺ T cells simultaneously producing IFN-γ, IL-2, and TNF-α than other test formulations. These effects were not compromised by PEI. Data from formulations that provided partial protection from challenge consistently identified specific immunological requirements necessary for protection. This approach may be useful for development of formulations for other vaccine platforms that also employ ubiquitous pathogens as carriers like the influenza virus.

Immune memory to Sudan virus: comparison between two separate disease outbreaks

Recovery from ebolavirus infection in humans is associated with the development of both cell-mediated and humoral immune responses. According to recent studies, individuals that did not survive infection with ebolaviruses appear to have lacked a robust adaptive immune response and the expression of several early innate response markers. However, a comprehensive protective immune profile has yet to be described. Here, we examine cellular memory immune responses among survivors of two separate Ebolavirus outbreaks (EVDs) due to Sudan virus (SUDV) infection in Uganda—Gulu 2000–2001 and Kibaale 2012. Freshly collected blood samples were stimulated with inactivated SUDV, as well as with recombinant SUDV or Ebola virus (EBOV) GP (GP_1–649). In addition, ELISA and plaque reduction neutralization assays were performed to determine anti-SUDV IgG titers and neutralization capacity. Cytokine expression was measured in whole blood cultures in response to SUDV and SUDV GP stimulation in both survivor pools, demonstrating recall responses that indicate immune memory. Cytokine responses between groups were similar but had distinct differences. Neutralizing, SUDV-specific IgG activity against irradiated SUDV and SUDV recombinant proteins were detected in both survivor cohorts. Furthermore, humoral and cell-mediated crossreactivity to EBOV and EBOV recombinant GP_1–649 was observed in both cohorts. In conclusion, immune responses in both groups of survivors demonstrate persistent recognition of relevant antigens, albeit larger cohorts are required in order to reach greater statistical significance. The differing cytokine responses between Gulu and Kibaale outbreak survivors suggests that each outbreak may not yield identical memory responses and promotes the merits of studying the immune responses among outbreaks of the same virus. Finally, our demonstration of cross-reactive immune recognition suggests that there is potential for developing cross-protective vaccines for ebolaviruses.

Development of therapeutics for treatment of Ebola virus infection

Ebola virus infection can cause Ebola virus disease (EVD). Patients usually show severe symptoms, and the fatality rate can reach up to 90%. No licensed medicine is available. In this review, development of therapeutics for treatment of Ebola virus infection and EVD will be discussed.

What clinicians should know about the 2014 Ebola outbreak

The ongoing Ebola outbreak that began in Guinea in February 2014 has spread to Liberia, Sierra Leone, Nigeria, Senegal, Spain, and the United States and has become the largest Ebola outbreak in recorded history. It is important for frontline medical providers to understand key aspects of Ebola virus disease (EVD) to quickly recognize an imported case, provide appropriate medical care, and prevent transmission. Furthermore, an understanding of the clinical presentation, clinical course, transmission, and prevention of EVD can help reduce anxiety about the disease and allow health care providers to calmly and confidently provide medical care to patients suspected of having EVD.

Outbreaks of Ebola virus disease in Africa: the beginnings of a tragic saga

The tremendous outbreak of Ebola virus disease occurring in West Africa since the end of 2013 surprises by its remoteness from previous epidemics and dramatic extent. This review aims to describe the 27 manifestations of Ebola virus that arose after its discovery in 1976. It provides an update on research on the ecology of Ebola viruses, modes of contamination and human transmission of the disease that are mainly linked to close contact with an infected animal or a patient suffering from the disease. The recommendations to contain the epidemic and challenges to achieve it are reminded.

Reverse genetics systems as tools for the development of novel therapies against filoviruses

Filoviruses cause severe hemorrhagic fevers with case fatality rates of up to 90%, for which no antivirals are currently available. Their categorization as biosafety level 4 agents restricts work with infectious viruses to a few maximum containment laboratories worldwide, which constitutes a significant obstacle for the development of countermeasures. Reverse genetics facilitates the generation of recombinant filoviruses, including reporter-expressing viruses, which have been increasingly used for drug screening and development in recent years. Further, reverse-genetics based lifecycle modeling systems allow modeling of the filovirus lifecycle without the need for a maximum containment laboratory and have recently been optimized for use in high-throughput assays. The availability of these reverse genetics-based tools will significantly improve our ability to find novel antivirals against filoviruses.

Modeling the lifecycle of Ebola virus under biosafety level 2 conditions with virus-like particles containing tetracistronic minigenomes

Ebola viruses cause severe hemorrhagic fevers in humans and non-human primates, with case fatality rates as high as 90%. There are no approved vaccines or specific treatments for the disease caused by these viruses, and work with infectious Ebola viruses is restricted to biosafety level 4 laboratories, significantly limiting the research on these viruses. Lifecycle modeling systems model the virus lifecycle under biosafety level 2 conditions; however, until recently such systems have been limited to either individual aspects of the virus lifecycle, or a single infectious cycle. Tetracistronic minigenomes, which consist of Ebola virus non-coding regions, a reporter gene, and three Ebola virus genes involved in morphogenesis, budding, and entry (VP40, GP1,2, and VP24), can be used to produce replication and transcription-competent virus-like particles (trVLPs) containing these minigenomes. These trVLPs can continuously infect cells expressing the Ebola virus proteins responsible for genome replication and transcription, allowing us to safely model multiple infectious cycles under biosafety level 2 conditions. Importantly, the viral components of this systems are solely derived from Ebola virus and not from other viruses (as is, for example, the case in systems using pseudotyped viruses), and VP40, GP1,2 and VP24 are not overexpressed in this system, making it ideally suited for studying morphogenesis, budding and entry, although other aspects of the virus lifecycle such as genome replication and transcription can also be modeled with this system. Therefore, the tetracistronic trVLP assay represents the most comprehensive lifecycle modeling system available for Ebola viruses, and has tremendous potential for use in investigating the biology of Ebola viruses in future. Here, we provide detailed information on the use of this system, as well as on expected results.

Clinical features and pathobiology of Ebolavirus infection

There has clearly been a deluge of international press coverage of the recent outbreak of Ebolavirus in Africa and is partly related to the "fear factor" that comes across when one is confronted with the fact that once infected, not only is the speed of death in a majority of cases rapid but also the images of the cause of death such as bleeding from various orifices gruesome and frightening. The fact that it leads to infection and death of health care providers (10% during the current epidemic) and the visualization of protective gear worn by these individuals to contain such infection adds to this "fear factor". Finally, there is a clear perceived notion that such an agent can be utilized as a bioterrorism agent that adds to the apprehension. Thus, in efforts to gain an objective view of the growing threat Ebolavirus poses to the general public, it is important to provide some basic understanding for the lethality of Ebolavirus infection that is highlighted in Fig. 1. This virus infection first appears to disable the immune system (the very system needed to fight the infection) and subsequently disables the vascular system that leads to blood leakage (hemorrhage), hypotension, drop in blood pressure, followed by shock and death. The virus appears to sequentially infect dendritic cells disabling the interferon system (one of the major host anti-viral immune systems) then macrophages (that trigger the formation of blood clots, release of inflammatory proteins and nitric oxide damaging the lining of blood vessels leading to blood leakage) and finally endothelial cells that contribute to blood leakage. The virus also affects organs such as the liver (that dysregulates the formation of coagulation proteins), the adrenal gland (that destroys the ability of the patient to synthesize steroids and leads to circulation failure and disabling of regulators of blood pressure) and the gastro-intestinal tract (leading to diarrhea). The ability of the virus to disable such major mechanisms in the body facilitates the ability of the virus to replicate in an uncontrolled fashion leading to the rapidity by which the virus can cause lethality. Various laboratories have been working on defining such mechanisms utilizing in vitro culture systems, a variety of animal models including inbred strains of normal and select gene knock out mice, guinea pigs and nonhuman primates that have led to a better understanding of the potential mechanisms involved. There have also been some major advances made in the identification of therapies from the very simple (major supportive type of therapy), to the identification of a number of highly effective chemotherapeutic agents, a variety of highly effective preventive (demonstrating 100% effectiveness in nonhuman primate models) recombinant formulations (adenovirus based, VSV-based, rabies virus based), therapeutic candidate vaccines (cocktail of monoclonal antibodies such as ZMAPP) and alternate approaches (RNAi-based such as TKM-Ebola and antisense based such as AVI-7537) that show great promise and at an unprecedented rate of discovery that speaks well for the scientific research community at large.

Ebola virus modulates transforming growth factor β signaling and cellular markers of mesenchyme-like transition in hepatocytes

Ebola virus (EBOV) causes a severe hemorrhagic disease in humans and nonhuman primates, with a median case fatality rate of 78.4%. Although EBOV is considered a public health concern, there is a relative paucity of information regarding the modulation of the functional host response during infection. We employed temporal kinome analysis to investigate the relative early, intermediate, and late host kinome responses to EBOV infection in human hepatocytes. Pathway overrepresentation analysis and functional network analysis of kinome data revealed that transforming growth factor (TGF-β)-mediated signaling responses were temporally modulated in response to EBOV infection. Upregulation of TGF-β signaling in the kinome data sets correlated with the upregulation of TGF-β secretion from EBOV-infected cells. Kinase inhibitors targeting TGF-β signaling, or additional cell receptors and downstream signaling pathway intermediates identified from our kinome analysis, also inhibited EBOV replication. Further, the inhibition of select cell signaling intermediates identified from our kinome analysis provided partial protection in a lethal model of EBOV infection. To gain perspective on the cellular consequence of TGF-β signaling modulation during EBOV infection, we assessed cellular markers associated with upregulation of TGF-β signaling. We observed upregulation of matrix metalloproteinase 9, N-cadherin, and fibronectin expression with concomitant reductions in the expression of E-cadherin and claudin-1, responses that are standard characteristics of an epithelium-to-mesenchyme-like transition. Additionally, we identified phosphorylation events downstream of TGF-β that may contribute to this process. From these observations, we propose a model for a broader role of TGF-β-mediated signaling responses in the pathogenesis of Ebola virus disease.

IMPORTANCE

Ebola virus (EBOV), formerly Zaire ebolavirus, causes a severe hemorrhagic disease in humans and nonhuman primates and is the most lethal Ebola virus species, with case fatality rates of up to 90%. Although EBOV is considered a worldwide concern, many questions remain regarding EBOV molecular pathogenesis. As it is appreciated that many cellular processes are regulated through kinase-mediated phosphorylation events, we employed temporal kinome analysis to investigate the functional responses of human hepatocytes to EBOV infection. Administration of kinase inhibitors targeting signaling pathway intermediates identified in our kinome analysis inhibited viral replication in vitro and reduced EBOV pathogenesis in vivo. Further analysis of our data also demonstrated that EBOV infection modulated TGF-β-mediated signaling responses and promoted "mesenchyme-like" phenotypic changes. Taken together, these results demonstrated that EBOV infection specifically modulates TGF-β-mediated signaling responses in epithelial cells and may have broader implications in EBOV pathogenesis.