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Plants express N-glycosylation pathways and produce N-glycosylated proteins but differ from the mammalian-type proteins. Therefore attempts are made to design and engineer plant glycosylation pathways that can produce mammalian-type glycosylated moieties so that large quantities of biopharmaceuticals compatible to the human body can be produced. Most of the studies of plant expression systems for molecular farming have been conducted on Nicotiana sp. and genetic engineering and molecular biology tools have enabled the generation of glycoengineered plant for human use in the production of therapeutic recombinant proteins. We have discussed in this chapter the advances of glycoengineering in plants with special reference to the reconstruction of silaylation pathways in plants and the latest application in the production of antibody and therapeutics in plants.

Zaire ebolavirus has been responsible for several catastrophic outbreaks with a high mortality rate. Unfortunately, there were no approved therapies or vaccines to treat or prevent infections caused by Ebola virus (EBOV) or other filoviruses. Atoltivimab/ maftivimab/odesivimab (Inmazeb) is the first Food and Drug Administration (FDA)-approved treatment for Zaire ebolavirus infection in adult and pediatric patients, including neonates born to a mother who is reverse transcription polymerase chain reaction (RT-PCR)-positive for Zaire ebolavirus infection. The efficacy of Inmazeb has been established in vivo and it has successfully completed a phase I clinical trial in healthy individuals with no drug-related adverse effects. Additionally, Inmazeb has displayed significant reduction in mortality in the PALM (PAmoja tuLinde Maisha) trial, when compared with the control arm receiving ZMapp. Inmazeb has received orphan drug designation from both the U.S. FDA and the European Medicines Agency (EMA).

The prevalence of the coronavirus disease 2019 (COVID-19) pandemic in its second year has led to massive global human and economic losses. The high transmission rate and the emergence of diverse SARS-CoV-2 variants demand rapid and effective approaches to preventing the spread, diagnosing on time, and treating affected people. Several COVID-19 vaccines are being developed using different production systems, including plants, which promises the production of cheap, safe, stable, and effective vaccines. The potential of a plant-based system for rapid production at a commercial scale and for a quick response to an infectious disease outbreak has been demonstrated by the marketing of carrot-cell-produced taliglucerase alfa (Elelyso) for Gaucher disease and tobacco-produced monoclonal antibodies (ZMapp) for the 2014 Ebola outbreak. Currently, two plant-based COVID-19 vaccine candidates, coronavirus virus-like particle (CoVLP) and Kentucky Bioprocessing (KBP)-201, are in clinical trials, and many more are in the preclinical stage. Interim phase 2 clinical trial results have revealed the high safety and efficacy of the CoVLP vaccine, with 10 times more neutralizing antibody responses compared to those present in a convalescent patient’s plasma. The clinical trial of the CoVLP vaccine could be concluded by the end of 2021, and the vaccine could be available for public immunization thereafter. This review encapsulates the efforts made in plant-based COVID-19 vaccine development, the strategies and technologies implemented, and the progress accomplished in clinical trials and preclinical studies so far.

The unprecedented 2013-2016 West Africa Ebola outbreak accelerated several medical countermeasures (MCMs) against Ebola virus disease (EVD). Several investigational products (IPs) were used throughout the outbreak but were not conclusive for efficacy results. Only the Randomized Controlled Trial (RCT) on ZMapp was promising but inconclusive. More recently, during the second-largest Ebola outbreak in North Kivu and Ituri provinces, Democratic Republic of the Congo (DRC), four IPs, including one small molecule (Remdesivir), two monoclonal antibody (mAb) cocktails (ZMapp and REGN-EB3) and a single mAb (mAb114), were evaluated in an RCT, the Pamoja Tulinde Maisha (PALM) study. Two products (REGN-EB3 and mAb114) demonstrated efficacy as compared to the control arm, ZMapp. There were remarkably few side effects recorded in the trial. The FDA approved both medications in this scientifically sound study, marking a watershed moment in the field of EVD therapy. These products can be produced relatively inexpensively and can be stockpiled. The administration of mAbs in EVD patients appears to be safe and effective, while several critical knowledge gaps remain; the impact of early administration of Ebola-specific mAbs on developing a robust immune response for future Ebola virus exposure is unknown. The viral mutation escape, leading to resistance, presents a potential limitation for single mAb therapy; further improvements need to be explored. Understanding the contribution of Fc-mediated antibody functions such as antibody-dependent cellular cytotoxicity (ADCC) of those approved mAbs is still critical. The potential merit of combination therapy and post-exposure prophylaxis (PEP) need to be demonstrated. Furthermore, the PALM trial has accounted for 30% of mortality despite the administration of specific treatments. The putative role of EBOV soluble Glycoprotein (sGP) as a decoy to the immune system, the virus persistence, and relapses might be investigated for treatment failure. The development of pan-filovirus or pan-species mAbs remains essential for protection. The interaction between FDA-approved mAbs and vaccines remains unclear and needs to be investigated. In this review, we summarize the efficacy and safety results of the PALM study and review current research questions for the further development of mAbs in pre-exposure or emergency post-exposure use.

Summary Background The ongoing Ebola virus outbreak in the Ituri and North Kivu Provinces of the Democratic Republic of the Congo, which began in July, 2018, is the second largest ever recorded. Despite civil unrest, outbreak control measures and the administration of experimental therapies and a vaccine have been initiated. The aim of this study was to test the efficacy of candidate therapies and diagnostic tests with the outbreak strain Ituri Ebola virus. Lacking a virus isolate from this outbreak, a recombinant Ituri Ebola virus was compared with a similarly engineered Makona virus from the 2013–16 outbreak. Methods Using Ebola virus sequences provided by organisations in DR Congo and a reverse genetics system, we generated an authentic Ebola virus from the ongoing outbreak in Ituri and North Kivu provinces. To relate this virus to other Ebola viruses in DR Congo, we did a phylogenetic analysis of representative complete Ebola virus genome sequences from previous outbreaks. We evaluated experimental therapies being tested in clinical trials in DR Congo, including remdesivir and ZMapp monoclonal antibodies, for their ability to inhibit the growth of infectious Ituri Ebola virus in cell culture. We also tested diagnostic assays for detection of the Ituri Ebola virus sequence. Findings The phylogenetic analysis of whole-genome sequences from each Ebola virus outbreak suggests there are at least two Ebola virus strains in DR Congo, which have independently crossed into the human population. The Ituri Ebola strain initially grew slower than the Makona strain, yet reached similar mean yields of 3 × 107 50% tissue culture infectious dose by 72 h infection in Huh-7 cells. Ituri Ebola virus was similar to Makona in its susceptibility to inhibition by remdesivir and to neutralisation by monoclonal antibodies from ZMapp and other monoclonal antibodies. Remdesivir inhibited Ituri Ebola virus at a 50% effective concentration (EC50) of 12nM (with a selectivity index of 303) and Makona Ebola virus at 13nM (with a selectivity index of 279). The Zmapp monoclonal antibodies 2G4 and 4G7 neutralised Ituri Ebola virus with a mean EC50 of 0·24 μg/mL and 0·48 μg/mL, and Makona Ebola virus with a mean EC50 of 0·45 μg/mL and 0·2 μg/mL. The Xpert Ebola and US Centers for Disease Control and Prevention real-time RT-qPCR diagnostic assays detected Ituri and Makona Ebola virus sequences with similar sensitivities and efficiencies, despite primer site binding mismatches in the Ituri Ebola virus. Interpretation Our findings provide a rationale for the continued testing of investigational therapies, confirm the effectiveness of the diagnostic assays used in the region, and establish a paradigm for the use of reverse genetics to inform response activities in an outbreak. Funding US Centers for Disease Control and Prevention.

Following the Ebola virus disease epidemic in west Africa, there has been increased awareness of the need for improved therapies for emerging diseases, including viral haemorrhagic fevers such as those caused by Ebola virus and other filoviruses. Our continually improving understanding of the virus life cycle coupled with the increased availability of ‘omics’ analyses and high-throughput screening technologies has enhanced our ability to identify potential viral and host factors and aspects involved in the infection process that might be intervention targets. In this Review we address compounds that have shown promise to various degrees in interfering with the filovirus life cycle, including monoclonal antibodies such as ZMapp, mAb114 and REGN-EB3 and inhibitors of viral RNA synthesis such as remdesivir and TKM-Ebola. Furthermore, we discuss the general potential of targeting aspects of the virus life cycle such as the entry process, viral RNA synthesis and gene expression, as well as morphogenesis and budding. In this Review, Hoenen, Groseth and Feldmann address strategies that have shown promise in interfering with the filovirus life cycle, including the entry process, viral RNA synthesis and gene expression, as well as morphogenesis and budding.

Summary Background The 2018 Ebola virus disease (EVD) outbreak in Equateur Province, Democratic Republic of the Congo, began on May 8, and was declared over on July 24; it resulted in 54 documented cases and 33 deaths. We did a retrospective genomic characterisation of the outbreak and assessed potential therapeutic agents and vaccine (medical countermeasures). Methods We used target-enrichment sequencing to produce Ebola virus genomes from samples obtained in the 2018 Equateur Province outbreak. Combining these genomes with genomes associated with known outbreaks from GenBank, we constructed a maximum-likelihood phylogenetic tree. In-silico analyses were used to assess potential mismatches between the outbreak strain and the probes and primers of diagnostic assays and the antigenic sites of the experimental rVSVΔG-ZEBOV-GP vaccine and therapeutics. An in-vitro flow cytometry assay was used to assess the binding capability of the individual components of the monoclonal antibody cocktail ZMapp. Findings A targeted sequencing approach produced 16 near-complete genomes. Phylogenetic analysis of these genomes and 1011 genomes from GenBank revealed a distinct cluster, confirming a new Ebola virus variant, for which we propose the name “Tumba”. This new variant appears to have evolved at a slower rate than other Ebola virus variants (0·69 × 10−3 substitutions per site per year with “Tumba” vs 1·06 × 10−3 substitutions per site per year without “Tumba”). We found few sequence mismatches in the assessed assay target regions and antigenic sites. We identified nine amino acid changes in the Ebola virus surface glycoprotein, of which one resulted in reduced binding of the 13C6 antibody within the ZMapp cocktail. Interpretation Retrospectively, we show the feasibility of using genomics to rapidly characterise a new Ebola virus variant within the timeframe of an outbreak. Phylogenetic analysis provides further indications that these variants are evolving at differing rates. Rapid in-silico analyses can direct in-vitro experiments to quickly assess medical countermeasures. Funding Defense Biological Product Assurance Office .

During the last two decades, the production of pharmaceutical proteins in plants evolved from proof of concept to established technology adopted by several biotechnological companies. This progress is particularly based on intensive research starting stable genetic transformation and moving to transient expression. Due to its advantages in yield and speed of protein production transient expression platforms became the leading plant-based manufacturing technology. Current transient expression methods rely on Agrobacteriummediated delivery of expression vectors into plant cells. In recent years, great advances have been made in the improvement of expression vectors, host cell engineering as well as in the development of commercial manufacturing processes. Several GMP-certified large-scale production facilities exist around the world to utilize agroinfiltration method. A number of pharmaceutical proteins produced by transient expression are currently in clinical development. The great potential of transient expression platform in respect to rapid response to emerging pandemics was demonstrated by the production of experimental ZMapp antibodies against Ebola virus as well as influenza vaccines. This review is focused on current design, status and future perspectives of plant transient expression system for the production of biopharmaceutical proteins.

The current Ebolavirus disease (EVD) outbreak in the provinces of North Kivu and Ituri is the tenth outbreak affecting the Democratic Republic of Congo (DRC); the first outbreak occurring in a war context, and the second most deadly Ebolavirus outbreak on record following the 2014 outbreak in West Africa. The DRC government's response consisted of applying a package of interventions including detection and rapid isolation of cases, contact tracing, population mapping, and identification of high-risk areas to inform a coordinated effort. The coordinated effort was to screen, ring vaccinate, and conduct laboratory diagnoses using GeneXpert (Cepheid) polymerase chain reaction. The effort also included ensuring safe and dignified burials and promoting risk communication, community engagement, and social mobilization. Following the adoption of the "Monitored Emergency Use of Unregistered Products Protocol," a randomized controlled trial of four investigational treatments (mAb114, ZMapp, and REGN-EB3 and Remdesivir) was carried out with all consenting patients with laboratory-confirmed EVD. REGN-EB3 and mAb114 showed promise as treatments for EVD. In addition, one investigational vaccine (rVSV-ZEBOV-GP) was used first, followed by a second prophylactic vaccine (Ad26.ZEBOV/MVA-BN-Filo) to reinforce the prevention. Although the provision of clinical supportive care remains the cornerstone of EVD outbreak management, the DRC response faced daunting challenges including general insecurity, violence and community resistance, appalling poverty, and entrenched distrust of authority. Ebolavirus remains a public health threat. A fully curative treatment is unlikely to be a game-changer given the settings of transmission, zoonotic nature, limits of effectiveness of any therapeutic intervention, and timing of presentation.

Ebola virus infection results in the fast onset of severe acute haemorrhagic fever with high mortality. The Ebola virus is labelled as a category A pathogen. Vaccines against the Ebola virus (EBOV) are essential for everyone, and an expansion in the arena of vaccine synthesis; especially, plant-based vaccine development has drawn attention. To express the heterologous protein for plant-based vectors, both RNA and DNA viruses have been adapted. Among the different approaches of plant-based vaccine technologies, the agroinfiltration method, which was initially established to investigate plant-virus interactions, has been considered an effective method to produce monoclonal antibodies against EBOV. The effectiveness of plants as bioreactors of vaccine/monoclonal antibodies development could be well-thought-out to attend the obligatory mandate. The review confers recent progress in the production of plant-based vaccines and antibody treatments against the Ebola virus disease, thereby alleviating public health alarms associated with EBOV.

Recent Ebola virus disease outbreaks affirm the dire need for treatments with proven efficacy. Randomized controlled clinical trials remain the gold standard but, during disease outbreaks, may be difficult to conduct due to ethical concerns and challenging field conditions. In the absence of a randomized control group, statistical modeling to create a control group could be a possibility. Such a model-based reference control would only be credible if it had the same mortality risk as that of the experimental group in the absence of treatment. One way to test this counterfactual assumption is to evaluate whether reasonable similarity exists across nonrandomized control groups from different clinical studies, which might suggest that a future control group would be similarly homogeneous. We evaluated similarity across six clinical studies conducted during the 2013-2016 West Africa outbreak of Ebola virus disease. These studies evaluated favipiravir, the biologic ZMapp, the antimalarial drug amodiaquine, or administration of convalescent plasma or convalescent whole blood. We compared the nonrandomized control groups of these six studies comprising 1147 individuals infected with Ebola virus. We found considerable heterogeneity, which did not disappear after statistical modeling to adjust for prognostic variables. Mortality risk varied widely (31 to 66%) across the nonrandomized control arms of these six studies. Models adjusting for baseline covariates (age, sex, and cycle threshold, a proxy for viral load) failed to sufficiently recalibrate these studies and showed that heterogeneity remained. Our findings highlight concerns about making invalid conclusions when comparing nonrandomized control groups to cohorts receiving experimental treatments.

Antibody therapy has been used to treat a variety of diseases and the success of ZMapp and other monoclonal antibody-based therapies during the 2014-2016 West African Ebola outbreak has shown this countermeasure can be a successful therapy for Ebola hemorrhagic fever. This study utilized transchromosomal bovines (TcB) vaccinated with a DNA plasmid encoding Ebola virus glycoprotein sequence to produce human polyclonal antibodies directed against Ebola virus glycoprotein. When administered 1 day postinfection, these TcB polyclonal antibodies provided partial protection and resulted in a 50% survival rate following a lethal challenge of Ebola virus Makona in rhesus macaques.

BACKGROUND: Several vaccine platforms have been successfully evaluated for prevention of Ebola virus (EBOV) disease (EVD) in nonhuman primates and humans. Despite remarkable efficacy by multiple vaccines, the immunological correlates of protection against EVD are incompletely understood. METHODS: We systematically evaluated the antibody response to various EBOV proteins in 79 nonhuman primates vaccinated with various EBOV vaccine platforms. We evaluated the serum immunoglobulin (Ig)G titers against EBOV glycoprotein (GP), the ability of the vaccine-induced antibodies to bind GP at acidic pH or to displace ZMapp, and virus neutralization titers. The correlation of these outcomes with survival from EVD was evaluated by appropriate statistical methods. RESULTS: Irrespective of the vaccine platform, protection from EVD strongly correlated with anti-GP IgG titers. The GP-directed antibody levels required for protection in animals vaccinated with virus-like particles (VLPs) lacking nucleoprotein (NP) was significantly higher than animals immunized with NP-containing VLPs or adenovirus-expressed GP, platforms that induce strong T-cell responses. Furthermore, protective immune responses correlated with anti-GP antibody binding strength at acidic pH, neutralization of GP-expressing pseudovirions, and the ability to displace ZMapp components from GP. CONCLUSIONS: These findings suggest key quantitative and qualitative attributes of antibody response to EVD vaccines as potential correlates of protection.

Ebola virus (EBOV) in humans causes a severe illness with high mortality rates. Several strategies have been developed in the past to treat EBOV infection, including the antibody cocktail ZMapp, which has been shown to be effective in nonhuman primate models of infection 1 and has been used under compassionate-treatment protocols in humans 2 . ZMapp is a mixture of three chimerized murine monoclonal antibodies (mAbs)3-6 that target EBOV-specific epitopes on the surface glycoprotein7,8. However, ZMapp mAbs do not neutralize other species from the genus Ebolavirus, such as Bundibugyo virus (BDBV), Reston virus (RESTV) or Sudan virus (SUDV). Here, we describe three naturally occurring human cross-neutralizing mAbs, from BDBV survivors, that target an antigenic site in the canonical heptad repeat 2 (HR2) region near the membrane-proximal external region (MPER) of the glycoprotein. The identification of a conserved neutralizing antigenic site in the glycoprotein suggests that these mAbs could be used to design universal antibody therapeutics against diverse ebolavirus species. Furthermore, we found that immunization with a peptide comprising the HR2-MPER antigenic site elicits neutralizing antibodies in rabbits. Structural features determined by conserved residues in the antigenic site described here could inform an epitope-based vaccine design against infection caused by diverse ebolavirus species.

Swiftly growing viruses are a major intimidation to human health. Such viruses are extremely pathogenic like Ebola virus, influenza virus, HIV virus, Zika virus etc . Ebola virus, a type of Filovirus, is an extremely infectious, single-stranded ribonucleic acid virus that infects both humans and apes, prompting acute fever with hemorrhagic syndrome. The high infectivity, severity and mortality of Ebola has plagued the world for the past fifty years with its first outbreak in 1976 in Marburg, Germany, and Frankfurt along with Belgrade and Serbia. The world has perceived about 28,000 cases and over 11,000 losses. The high lethality of Ebola makes it a candidate for use in bioterrorism thereby arising more concern. New guidelines have been framed for providing best possible care to the patients suffering from Ebola virus i.e Grading of Recommendation Assessment, Development And Evaluation (GRADE) methodology to develop evidence-based strategy for the treatment in future outbreak of Ebola virus. No drugs have been approved, while many potent drugs like rVSV-EBOV, Favipiravir, ZMapp are on clinical test for human safety. In this review we will discover and discuss perspective aspects that lead to the evolution of different Ebola variants as well as advances in various drugs and vaccines for treatment of the disease.

During the 2013-2016 west African Ebola outbreak that affected West Africa, accelerated clinical trials, testing unproven but promising and potentially lifesaving experimental interventions emerged as a key component of the global outbreak. In 2017, no Ebola medical countermeasures had proven antiviral efficacy in patients. However, in September 2014, the World Health Organization inventoried a list of potential drug candidates developed or repurposed with demonstrated antiviral efficacy in vitro or in animal models. Numerous therapeutics were considered or explored during the outbreak, including nucleoside and nucleotide analogues, nucleic acid-based drugs and immunotherapeutics. Drugs in clinical trials were tested within the framework of optimized supportive care with fluids and electrolytes and management of severe compromise of multiple organs resulting from viral cytopathology and immune-mediated cell damage. Assessment of those therapeutics with encouraging preliminary efficacy or safety profile, like the repurposed direct antiviral agent favipiravir or the combination of antibodies ZMapp requires further investigation to confirm their efficacy in humans, propose appropriate doses and evaluate the possibility of treatment combinations. During the lull before the next epidemic, major challenges for managing future Ebola epidemics include scientific, clinical and public health preparedness with establishment of innovative patient care and clinical research support in remote poor areas where Ebola and other deadly infectious diseases typically reemerge.

The 2013-2016 Ebola outbreak highlighted the limited treatment options and lack of rapid response strategies for emerging pathogen outbreaks. Here, we propose an efficient development cycle using glycoengineered Pichia pastoris to produce monoclonal antibody cocktails against pathogens. To enable rapid genetic engineering of P. pastoris, we introduced a genomic landing pad for reliable recombinase-mediated DNA integration. We then created strains expressing each of the three monoclonal antibodies that comprise the ZMapp cocktail, and demonstrated that the secreted antibodies bind to the Ebola virus glycoprotein by immunofluorescence assay. We anticipate that this approach could accelerate the production of therapeutics against future pathogen outbreaks.

Opinion statement Purpose of review Ebola virus, a member of the Filoviridae family, is a causative agent of severe viral hemorrhagic fever in humans. Over the past 40 years, the virus has been linked to several high mortality outbreaks in Africa with the recent West African outbreak resulting in over 11,000 deaths. This review provides a summary of the status of the drug discovery and development process for therapeutics for Ebola virus disease, with a focus on the strategies being used and the challenges facing each stage of the process. Recent findings Despite the wealth of in vitro efficacy data, preclinical data in animal models, and human clinical data, no therapeutics have been approved for the treatment of Ebola virus disease. However, several promising candidates, such as ZMapp and GS-5734, have advanced into ongoing clinical trials. Summary The gravity of the 2014-2016 outbreak spurred a heightened effort to identify and develop new treatments for Ebola virus disease, including small molecules, immunotherapeutics, host factors, and clinical disease management options. Disclaimer Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endoresed by the U.S. Army.

In 2014, the World Health Organization was notified of an outbreak of a communicable disease characterized by fever, severe diarrhea, vomiting, and a high fatality rate in Guinea. Virologic investigation identified Zaire ebolavirus (EBOV) as the causative agent. Approximately 30 years after the first epidemic, there is no vaccine or therapeutic medication approved to counter the Ebola virus. In this review, it emphasized that plant based antibodies can be an effective cure to Ebola hemorrhagic fever. Genetically modified Nicotiana benthamiana is used to manufacture ZMapp drug by Kentucky BioProcessing. ZMapp three-antibody cocktail binds to the Ebola virus to deactivate it and provides simulated immune response against sugar-tagged proteins on the outside of the Ebola virus, which had verified efficacy against Ebola infection in nonhuman primates and also successfully treated two American medical workers infected with Ebola virus disease.

The 2014–2016 Ebola virus outbreak in West Africa was the deadliest in history, prompting the evaluation of various drug candidates, including antibody-based therapeutics for the treatment of Ebola hemorrhagic fever (EHF). Prior to 2014, only convalescent blood products from EHF survivors had been administered to newly infected individuals as a form of treatment. However, during the recent outbreak, monoclonal antibody cocktails such as ZMapp, ZMAb and MB-003 were either tested in a human clinical safety and efficacy trial or provided to some based on compassionate grounds. This review aims to discuss the evolution of antibody-based treatments for EHF, their clinical trial efficacy and the development of new antibody-based therapies currently advancing in preclinical testing.

Despite the unprecedented Ebola virus outbreak response in West Africa, no Ebola medical countermeasures have been approved by the US Food and Drug Administration. However, multiple valuable lessons have been learned about the conduct of clinical research in a resource-poor, high risk–pathogen setting. Numerous therapeutics were explored or developed during the outbreak, including repurposed drugs, nucleoside and nucleotide analogues (BCX4430, brincidofovir, favipiravir, and GS-5734), nucleic acid–based drugs (TKM-Ebola and AVI-7537), and immunotherapeutics (convalescent plasma and ZMapp). We review Ebola therapeutics progress in the aftermath of the West Africa Ebola virus outbreak and attempt to offer a glimpse of a path forward.

Ebola virus disease (EVD), formerly known as Ebola hemorrhagic fever, is a re-emerging zoonotic disease that has caused periodic outbreaks since the first reported outbreak in 1976. In 2014, in West Africa, the largest outbreak of Ebola virus in history emerged, affecting close to 30,000 people; more than 10,000 of these individuals died. This virus, which causes fatal hemorrhagic fever in humans and non-human primates, has the highest mortality rate (25-90%) among the viral hemorrhagic fever diseases. Ebola virus is transmitted through the blood and body fluids of infected animals and humans, as well as through contaminated materials. The virus is often spread in the hospital setting, and it is classified as a biosafety level 4 agent. Accordingly, diagnostic procedures and infected patient care should be performed at the highest safety levels. The potential therapies and vaccines against EVD have continued developing or been used in emergency situations during last outbreak. Some of these include the chimpanzee adenovirus type-3 and recombinant vesicular stomatitis virus-Ebola vaccines and new treatment modalities, such as passive immunization, brincidofovir, and ZMapp. Although these trials have shown different levels of success, there are no standardized treatments or vaccines that have been approved for humans. Such prevention is the only way to reduce human infection and the spread of outbreaks and is primarily based on personal protection measures and raising awareness of the risk factors.

Plants have great potential as photosynthetic factories to produce pharmaceutically important and commercially valuable biomedicines and industrial proteins at low cost. The U.S. Food and Drug Administration (U.S. FDA) has approved the drug Elelyso (taliglucerase alfa) produced by carrot cells for treatment of type 1 Gaucher's disease in 2012. The commercial potential of biomedicines produced by molecular farming has dramatically improved due to the success of an experimental drug called ZMapp, which has immunological activity in Ebola patients. A cocktail of three monoclonal antibodies was produced in tobacco (Nicotiana benthamiana) plants (Chen and Davis 2016). At present, very few drugs made by this technology have been approved by worldwide authorities such as the U.S. FDA. However, plants have been proposed as a novel paradigm for commercial production of proteins over the next decade. In recent years, leading researchers on molecular farming have given more priority to the area of animal-free therapeutic proteins such as parenteral and oral vaccines. Although plant-based platforms have considerable advantages over traditional systems such as bacterial and animal systems, there are several obstacles to commercial-scale production, especially with regards to improving the quality and quantity of plant-produced biologics and industrial materials. One of the biggest barriers to commercialization of this technology is the intense scrutiny of these new plant varieties by regulatory agencies and the public as well as the high costs associated with their regulatory approval.

Summary Background The real-time generation of information about pathogen genomes has become a vital goal for transmission analysis and characterisation in rapid outbreak responses. In response to the recently established genomic capacity in the Democratic Republic of the Congo, we explored the real-time generation of genomic information at the start of the 2018 Ebola virus disease (EVD) outbreak in North Kivu Province. Methods We used targeted-enrichment sequencing to produce two coding-complete Ebola virus genomes 5 days after declaration of the EVD outbreak in North Kivu. Subsequent sequencing efforts yielded an additional 46 genomes. Genomic information was used to assess early transmission, medical countermeasures, and evolution of Ebola virus. Findings The genomic information demonstrated that the EVD outbreak in the North Kivu and Ituri Provinces was distinct from the 2018 EVD outbreak in Equateur Province of the Democratic Republic of the Congo. Primer and probe mismatches to Ebola virus were identified in silico for all deployed diagnostic PCR assays, with the exception of the Cepheid GeneXpert GP assay. Interpretation The first two coding-complete genomes provided actionable information in real-time for the deployment of the rVSVΔG-ZEBOV-GP Ebola virus envelope glycoprotein vaccine, available therapeutics, and sequence-based diagnostic assays. Based on the mutations identified in the Ebola virus surface glycoprotein (GP12) observed in all 48 genomes, deployed monoclonal antibody therapeutics (mAb114 and ZMapp) should be efficacious against the circulating Ebola virus variant. Rapid Ebola virus genomic characterisation should be included in routine EVD outbreak response procedures to ascertain efficacy of medical countermeasures. Funding Defense Biological Product Assurance Office.

Background Management of Ebola virus disease (EVD) has historically focused on infection prevention, case detection and supportive care. Several specific anti-Ebola therapies have been investigated, including during the 2014–2016 West African outbreak. Our objective was to conduct a systematic review of the effect of anti-Ebola virus therapies on clinical outcomes to guide their potential use and future evaluation. Methods We searched PubMed, EMBASE, Global Health, Cochrane Library, African Index Medicus, WHOLIS (inception-9 April 2018), and trial registries for observational studies or clinical trials, in any language, that enrolled patients with confirmed EVD who received therapy targeting Ebola virus and reported on mortality, symptom duration, or adverse effects. Results From 11,257 citations and registered trials, we reviewed 55 full-text citations, of which 35 met eligibility criteria (1 randomized clinical trial (RCT), 8 non-randomized comparative studies, 9 case series and 17 case reports) and collectively examined 21 anti-Ebola virus agents. The 31 studies performed during the West African outbreak reported on 4.8% (1377/28616) of all patients with Ebola. The only RCT enrolled 72 patients (0.25% of all patients with Ebola) and compared the monoclonal antibody ZMapp vs. standard care (mortality, 22% vs. 37%; 95% confidence interval for risk difference, − 36 to 7%). Studies of convalescent plasma, interferon-β-1a, favipiravir, brincidofovir, artesunate-amodiaquine and TKM-130803 were associated with at least moderate risk of bias. Conclusions Research evaluating anti-Ebola virus agents has reached very few patients with EVD, and inferences are limited by non-randomized study designs. ZMapp has the most promising treatment signal. Electronic supplementary material The online version of this article (10.1186/s12879-019-3980-9) contains supplementary material, which is available to authorized users.

The human B cell response to natural filovirus infections early after recovery is poorly understood. Previous serologic studies suggest that some Ebola virus survivors exhibit delayed antibody responses with low magnitude and quality. Here, we sought to study the population of individual memory B cells induced early in convalescence. We isolated monoclonal antibodies (MAbs) from memory B cells from four survivors treated for Ebola virus disease (EVD) 1 or 3 months after discharge from the hospital. At the early time points postrecovery, the frequency of Ebola-specific B cells was low and dominated by clones that were cross-reactive with both Ebola glycoprotein (GP) and with the secreted GP (sGP) form. Of 25 MAbs isolated from four donors, only one exhibited neutralization activity. This neutralizing MAb, designated MAb EBOV237, recognizes an epitope in the glycan cap of the surface glycoprotein. In vivo murine lethal challenge studies showed that EBOV237 conferred protection when given prophylactically at a level similar to that of the ZMapp component MAb 13C6. The results suggest that the human B cell response to EVD 1 to 3 months postdischarge is characterized by a paucity of broad or potent neutralizing clones. However, the neutralizing epitope in the glycan cap recognized by EBOV237 may play a role in the early human antibody response to EVD and should be considered in rational design strategies for new Ebola virus vaccine candidates. IMPORTANCE The pathogenesis of Ebola virus disease (EVD) in humans is complex, and the mechanisms contributing to immunity are poorly understood. In particular, it appears that the quality and magnitude of the human B cell response early after recovery from EVD may be reduced compared to most viral infections. Here, we isolated human monoclonal antibodies from B cells of four survivors of EVD at 1 or 3 months after hospital discharge. Ebola-specific memory B cells early in convalescence were low in frequency, and the antibodies they encoded demonstrated poor neutralizing potencies. One neutralizing antibody that protected mice from lethal infection, EBOV237, was identified in the panel of 25 human antibodies isolated. Recognition of the glycan cap epitope recognized by EBOV237 suggests that this antigenic site should be considered in vaccine design and treatment strategies for EVD.

Ebola virus (EV) is a highly contagious infectious agent that causes hemorrhagic fever and bleeding in human and nonhuman primates. Ebola contains a single, non-segmented, single-stranded RNA and thus belongs to the order Mononegavirales. EVD is a highly transmittable and zoonotic disease, i.e., transmitted from animal to human and human to human through blood and body secretions. During replication of Ebola genome, it is highly prone to occurrence of mutations as RDRP (L protein) makes errors during replication and a proofreading mechanism is lacking in Ebola. At present, there is no FDA-approved drug or vaccine available agai5nst Ebola virus, although some promising drug candidates against Ebola virus are in clinical trial (favipiravir (T-705, AVI-7537)). The current book chapter will provide a general understanding to the researchers about the physiology, molecular genetics, its virulence, therapeutic options, and putative drug targets, repurposing the existing drugs for better prevention and understanding about the Ebola virus.

In the West Africa epidemic from a virus as lethal as Ebola, pregnant women and their infants were denied access to potentially life-saving drugs and an experimental vaccine. From the discovery of the Ebola virus in 1976 to the start of the West African Ebola epidemic, pregnant women had a case fatality rate of approximately 90%; no fetus, neonate, or mother-baby pair had survived the infection; and there were no effective drugs or vaccines. When Ebola virus disease (EVD) began its spread throughout Sierra Leone, Guinea, and Liberia, numerous protocols for clinical trials of promising highly effective antiviral drugs and vaccines were evaluated, but the protocols excluded pregnant women and their infants from participation. This exclusion of pregnant women from clinical trials had a long precedent, but had been temporarily halted during the AIDS pandemic. Despite the expected 90% mortality rate for pregnant women and total loss of life for their fetuses and newborns, decisions were made to withhold potentially life-saving treatments from them. Fortunately, a single newborn was able to receive experimental treatment outside of the clinical trial while being cared for by Medecins Sans Frontieres—she became the only known neonate to survive EVD. This chapter discusses the survival statistics of pregnant women and fetuses with Ebola infection from both previous outbreaks and the West African epidemic and addresses issues surrounding the exclusion of pregnant women and their infants from receiving potentially life-saving treatment during clinical trials.

In recent times, plant molecular farming (PMF) in plant expression hosts has attracted a lot of interest for production of modern human therapeutics. Its advantages include presence of inherent posttranslational modifications, lower cost, safety, ecofriendly, easy scale-up, and fewer regulatory issues. Interestingly, plant hosts impart “natural protection” to human therapeutic recombinant products by default, since they are inherently incapable of harboring/propagating human pathogens. Plants being eukaryotes, it was expected that active versions of human proteins produced within them would resemble natural human proteins. However, it was not found to necessarily be so, owing to inherent differences in the glycosylation patterns of the two hosts. A prerequisite for successful therapeutic applications of PMF-based biopharmaceuticals would be to have them glycosylated in human compatible precise patterns. Glycoengineering technology, wherein the genes of plant specific glycosyltransferases are replaced with their human counterparts, is proving to be a practical approach in modifying the PMF-based products in order to tailor them for human utility. A few such “humanized” products, termed “Biosimilars” and “Biobetters,” actually display the desired effectiveness and functional value. Human Growth Hormone (hGH), surface antigen of Hepatitis B (HBsAg), Hepatitis vaccine ZMapp, and FDA approved enzyme ELELYSO have already been harvested from plant expression systems. This chapter mainly discusses the glycosylation motifs of human biopharmaceutics expressed in plant host systems, the pros combined with cons of using such hosts, the possibility of utilizing plant cell culture, and finally the scope of developing better, cheaper and “humanized” products via glycoengineering methods.

Background: The ongoing Ebola virus (EBOV) outbreak in the Ituri and North Kivu provinces of the Democratic Republic of Congo (DRC) is the second largest ever recorded. Despite civil unrest, outbreak control measures, and the administration of experimental therapies and a vaccine, have been initiated. Lacking a virus isolate from this outbreak, we rescued recombinant, infectious EBOV-Ituri virus from plasmid DNA. Methods: We report a phylogenetic analysis of EBOV-Ituri. In addition, we evaluated experimental therapeutics currently undergoing clinical trials in DRC: remdesivir (GS-5734) and ZMapp monoclonal antibodies (mAbs) to inhibit EBOVI-Ituri. We also tested diagnostic assays used in DRC for detection of the EBOV-Ituri sequence despite having mismatches in the primer binding sites. EBOV-Ituri results were compared with the 2013-2016 outbreak EBOV-Makona. Findings: Our analysis suggests there are at least 2 EBOV strains in DRC, which have independently crossed into the human population. The EBOV-Ituri strain initially grew significantly slower than EBOV-Makona from the 2013-2016 outbreak, yet reached similar titers by 72H p.i. EBOV-Ituri was similar to EBOV-Makona in its susceptibility to inhibition by remdesivir, neutralizing ZMapp, and other EBOV mAbs. The Xpert Ebola and CDC RT-qPCR diagnostic assays detected EBOV-Ituri with high sensitivity despite primer site binding mismatches. Interpretation: Our findings provide a rationale for the continued testing of investigational therapies, confirm the effectiveness of the diagnostic assay used in the region, and establish a paradigm for the use of reverse genetics-launched strains to inform response activities in an ongoing outbreak. Funding: US Centers for Disease Control and Prevention. Declaration of Interest: Danielle Porter is an employee of Gilead. Ethical Approval: Not needed.

MIL77, which has a higher manufacturing capacity than ZMapp, comprises MIL77-1, MIL77-2, and MIL77-3. The mechanisms by which these antibodies inhibit glycoprotein are unclear. Infection by viruses with lipid-bilayer envelopes occurs via the fusion of the viral membrane with the membrane of the target cell. Therefore, the interaction between the antibodies and the EBOV membrane is crucial. We examined the interactions between MIL77 and the viral membrane using SPR. MIL77-1 selectively binds to viral membranes, while MIL77-2 and MIL77-3 do not. MIL77-1’s ability to screen the more rigid domains of the membranes results in a locally increased concentration of the drug at the fusion site. Although MIL77-2 recognizes an epitope of GP, it is not necessary in the MIL77 cocktail. These results highlight the importance of EBOV membrane interactions in improving the efficiency of a neutralizing antibody. Furthermore, the viral membrane may be an important target of antibodies against EBOV.

The Ebola virus, formally known as the Ebola hemorrhagic fever, is an acute viral syndrome causing sporadic outbreaks that have ravaged West Africa. Due to its extreme virulence and highly transmissible nature, Ebola has been classified as a category A bioweapon organism. Only recently have vaccine or drug regimens for the Ebola virus been developed, including Zmapp and peptides. In addition, existing drugs which have been repurposed toward anti-Ebola virus activity have been re-examined and are seen to be promising candidates toward combating Ebola. Drug development involving computational tools has been widely employed toward target-based drug design. Screening large libraries have greatly stimulated research toward effective anti-Ebola virus drug regimens. Current emphasis has been placed on the investigation of host proteins and druggable viral targets. There is a huge gap in the literature regarding guidelines in the discovery of Ebola virus inhibitors, which may be due to the lack of information on the Ebola drug targets, binding sites, and mechanism of action of the virus. This review focuses on Ebola virus inhibitors, drugs which could be repurposed to combat the Ebola virus, computational methods which study drug-target interactions as well as providing further insight into the mode of action of the Ebola virus.