Ebola-specific therapeutic antibodies from lab to clinic: The example of ZMapp

In the 1990s, monoclonal antibodies (mAbs) progressed from scientific tools to advanced therapeutics, particularly for the treatment of cancers and autoimmune and inflammatory disorders. In the arena of infectious disease, the inauguration of mAbs as a post-exposure treatment in humans against Ebola virus (EBOV) occurred in response to the 2013-2016 West Africa outbreak. This review recounts the history of a candidate mAb treatment, ZMapp, beginning with its emergency use in the 2013-2016 outbreak and advancing to randomized controlled trials into the 2018-2020 African outbreak. We end with a brief discussion of the hurdles and promise toward mAb therapeutic use against infectious disease.

Two-way pharmacodynamic modeling of drug combinations and its application to pairs of repurposed Ebola and SARS-CoV-2 agents

Existing pharmacodynamic (PD) mathematical models for drug combinations discriminate antagonistic, additive, multiplicative, and synergistic effects, but fail to consider how concentration-dependent drug interaction effects may vary across an entire dose-response matrix. We developed a two-way pharmacodynamic (TWPD) model to capture the PD of two-drug combinations. TWPD captures interactions between upstream and downstream drugs that act on different stages of viral replication, by quantifying upstream drug efficacy and concentration-dependent effects on downstream drug pharmacodynamic parameters. We applied TWPD to previously published in vitro drug matrixes for repurposed potential anti-Ebola and anti-SARS-CoV-2 drug pairs. Depending on the drug pairing, the model recapitulated combined efficacies as or more accurately than existing models and can be used to infer efficacy at untested drug concentrations. TWPD fits the data slightly better in one direction for all drug pairs, meaning that we can tentatively infer the upstream drug. Based on its high accuracy, TWPD could be used in concert with PK models to estimate the therapeutic effects of drug pairs in vivo.

Evaluation of fendiline treatment in VP40 system with nucleation-elongation process: a computational model of Ebola virus matrix protein assembly

Ebola virus (EBOV) infection is threatening human health, especially in Central and West Africa. Limited clinical trials and the requirement of biosafety level-4 laboratories hinder experimental work to advance our understanding of EBOV and the evaluation of treatment. In this work, we use a computational model to study the assembly and budding process of EBOV and evaluate the effect of fendiline on these processes in the context of fluctuating host membrane lipid levels. Our results demonstrate for the first time that the assembly of VP40 filaments may follow the nucleation-elongation theory, as this mechanism is critical to maintaining a pool of VP40 dimers for the maturation and production of virus-like particles (VLPs). We further find that this nucleation-elongation process is likely influenced by fluctuating phosphatidylserine (PS), which can complicate the efficacy of lipid-targeted therapies like fendiline, a drug that lowers cellular PS levels. Our results indicate that fendiline-induced PS reduction may actually increase VLP production at earlier time points (24 h) and under low fendiline concentrations (≤2 µM). However, this effect is transient and does not change the conclusion that fendiline generally decreases VLP production. In the context of fluctuating PS levels, we also conclude that fendiline can be more efficient at the late stage of VLP budding relative to earlier phases. Combination therapy with a VLP budding step-targeted drug may therefore further increase the treatment efficiency of fendiline. Finally, we also show that fendiline-induced PS reduction more effectively lowers VLP production when VP40 expression is high. Taken together, our results provide critical quantitative information on how fluctuating lipid levels (PS) affect EBOV assembly and egress and how this mechanism can be disrupted by lipid-targeting molecules like fendiline.

IMPORTANCE

Ebola virus (EBOV) infection can cause deadly hemorrhagic fever, which has a mortality rate of ~50%-90% without treatment. The recent outbreaks in Uganda and the Democratic Republic of the Congo illustrate its threat to human health. Though two antibody-based treatments were approved, mortality rates in the last outbreak were still higher than 30%. This can partly be due to the requirement of advanced medical facilities for current treatments. As a result, it is very important to develop and evaluate new therapies for EBOV infection, especially those that can be easily applied in the developing world. The significance of our research is that we evaluate the potential of lipid-targeted treatments in reducing EBOV assembly and egress. We achieved this goal using the VP40 system combined with a computational approach, which both saves time and lowers cost compared to traditional experimental studies and provides innovative new tools to study viral protein dynamics.

Oral administration of obeldesivir protects nonhuman primates against Sudan ebolavirus

Obeldesivir (ODV, GS-5245) is an orally administered prodrug of the parent nucleoside of remdesivir (RDV) and is presently in phase 3 trials for COVID-19 treatment. In this work, we show that ODV and its circulating parent nucleoside metabolite, GS-441524, have similar in vitro antiviral activity against filoviruses, including Marburg virus, Ebola virus, and Sudan virus (SUDV). We also report that once-daily oral ODV treatment of cynomolgus monkeys for 10 days beginning 24 hours after SUDV exposure confers 100% protection against lethal infection. Transcriptomics data show that ODV treatment delayed the onset of inflammation and correlated with antigen presentation and lymphocyte activation. Our results offer promise for the further development of ODV to control outbreaks of filovirus disease more rapidly.

An oral antiviral for Ebola disease

For those exposed to filovirus, such as Sudan virus and Ebola virus, a new study offers hope.

Antiviral Protein-Protein Interaction Inhibitors

Continually repeating outbreaks of pathogenic viruses necessitate the construction of effective antiviral strategies. Therefore, the development of new specific antiviral drugs in a well-established and efficient manner is crucial. Taking into account the strong ability of viruses to change, therapies with diversified molecular targets must be sought. In addition to the widely explored viral enzyme inhibitor approach, inhibition of protein-protein interactions is a very valuable strategy. In this Perspective, protein-protein interaction inhibitors targeting HIV, SARS-CoV-2, HCV, Ebola, Dengue, and Chikungunya viruses are reviewed and discussed. Antibodies, peptides/peptidomimetics, and small molecules constitute three classes of compounds that have been explored, and each of them has some advantages and disadvantages for drug development.

Effect of anti-Ebola virus monoclonal antibodies on endogenous antibody production in survivors of Ebola virus disease in the Democratic Republic of the Congo: an observational cohort study

BACKGROUND

The use of specific anti-Ebola virus therapy, especially monoclonal antibodies, has improved survival in patients with Ebola virus disease. We aimed to assess the effect of monoclonal antibodies on anti-Ebola virus antibody responses in survivors of the 2018-20 Ebola outbreak in the Democratic Republic of the Congo.

METHODS

In this observational prospective cohort study, participants were enrolled at three Ebola survivor clinics in Beni, Mangina, and Butembo (Democratic Republic of the Congo). Eligible children and adults notified as survivors of Ebola virus disease (ie, who had confirmed Ebola virus disease [RT-PCR positive in blood sample] and were subsequently declared recovered from the virus [RT-PCR negative in blood sample] with a certificate of recovery from Ebola virus disease issued by an Ebola treatment centre) during the 2018-20 Ebola virus disease outbreak were invited to participate in the study. Participants were recruited on discharge from Ebola treatment centres and followed up for 12-18 months depending on recruitment date. Routine follow-up assessments were done at 1, 3, 6, and 12-18 months after inclusion. We collected sociodemographic (age, sex, visit site), clinical (anti-Ebola virus drugs), and laboratory data (RT-PCR and Ct values). The primary outcome was the antibody concentrations against Ebola virus glycoprotein, nucleoprotein, and 40-kDa viral protein antigens over time assessed in all participants. Antibody concentrations were measured by the multiplex immunoassay, and the association between anti-Ebola virus antibody levels and the relevant exposures, such as anti-Ebola virus disease drugs (ansuvimab, REGN-EB3, ZMapp, or remdesivir), was assessed using both linear and logistic mixed regression models. This study is registered at ClinicalTrials.gov, NCT04409405.

FINDINGS

Between April 16, 2020, and Oct 18, 2021, 1168 survivors were invited to participate in the Les Vainqueurs d'Ebola cohort study. 787 survivors were included in the study, of whom 358 had data available for antibody responses. 85 (24%) of 358 were seronegative for at least two Ebola virus antigens on discharge from the Ebola treatment centre. The antibody response over time fluctuated but a continuous decrease in an overall linear evolution was observed. Quantitative modelling showed a decrease in nucleoprotein, glycoprotein, and VP-40 antibody concentrations over time (p<0·0001) with the fastest decrease observed for glycoprotein. The probability of being seropositive for at least two antigens after 36 months was 53·6% (95% CI 51·6-55·6) for participants who received ansuvimab, 73·5% (71·5-75·5) for participants who received REGN-EB3, 76·8% (74·8-78·8) for participants who received remdesivir, and 78·5% (76·5-80·5) for participants who received ZMapp.

INTERPRETATION

Almost a quarter of survivors were seronegative on discharge from the Ebola treatment centre and antibody concentrations decreased rapidly over time. These results indicate that monoclonal antibodies might negatively affect the production of anti-Ebola virus antibodies in survivors of Ebola virus disease which could increase the risk of reinfection or reactivation.

FUNDING

The French National Agency for AIDS Research-Emergent Infectious Diseases-The French National Institute of Health and Medical Research, the French National Research Institute for Development, and the European and Developing Countries Clinical Trials Partnership.

TRANSLATION

For the French translation of the abstract see Supplementary Materials section.

The Utilization and Development of Viral Vectors in Vaccines as a Prophylactic Treatment Against Ebola Virus as an Emerging and Zoonotic Infectious Disease

Alongside the prescription of commonly used antivirals, such as acyclovir, remdesivir, oseltamivir, and ciprofloxacin, the most efficient way to prevent or treat communicable diseases is by vaccination. Vaccines have been the most efficient way to prevent or treat highly transmissible infectious agents, such as Ebola, Anthrax, and Dengue Fever. Most epidemics of these highly transmissible infectious agents occur in places, such as South America, Central America, Tropical Asia, and Africa, where the availability of resources and access to adequate healthcare are limited. However, recent events in history have proven that even with access to resources and proper healthcare, those in firstworld countries are not invincible when it comes to infectious diseases and epidemics. The Ebola virus outbreak in West Africa highlighted the gaps in therapeutic advancement and readiness and led to the rapid development of novel vaccine approaches. Viral vectors, in the case of the Ebola vaccine the Vesicular Stomatitis Virus (VSV), can be safely used to activate or initiate the innate adaptive immune response to protect against viral infection. When developed properly and with extensive study, novel vaccine approaches allow physicians and health experts to control the rate at which viruses spread or prevent transmission. This review will discuss the advantages of viral vector vaccines, their chemistry and development, and the pathophysiology of the Ebola virus to develop advantageous and efficacious treatments.

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.

Novel Antiviral Molecules against Ebola Virus Infection

Infection with Ebola virus (EBOV) is responsible for hemorrhagic fever in humans with a high mortality rate. Combined efforts of prevention and therapeutic intervention are required to tackle highly variable RNA viruses, whose infections often lead to outbreaks. Here, we have screened the 2P2I3D chemical library using a nanoluciferase-based protein complementation assay (NPCA) and isolated two compounds that disrupt the interaction of the EBOV protein fragment VP35IID with the N-terminus of the dsRNA-binding proteins PKR and PACT, involved in IFN response and/or intrinsic immunity, respectively. The two compounds inhibited EBOV infection in cell culture as well as infection by measles virus (MV) independently of IFN induction. Consequently, we propose that the compounds are antiviral by restoring intrinsic immunity driven by PACT. Given that PACT is highly conserved across mammals, our data support further testing of the compounds in other species, as well as against other negative-sense RNA viruses.

Contextual determinants of mass drug administration performance: Modelling fourteen years of lymphatic filariasis treatments in West Africa

BACKGROUND

Effective mass drug administration (MDA) is the cornerstone in the elimination of lymphatic filariasis (LF) and a critical component in combatting all neglected tropical diseases for which preventative chemotherapy is recommended (PC-NTDs). Despite its importance, MDA coverage, however defined, is rarely investigated systematically across time and geography. Most commonly, investigations into coverage react to unsatisfactory outcomes and tend to focus on a single year and health district. Such investigations omit more macro-level influences including sociological, environmental, and programmatic factors. The USAID NTD database contains measures of performance from thousands of district-level LF MDA campaigns across 14 years and 10 West African countries. Specifically, performance was measured as an MDA's epidemiological coverage, calculated as persons treated divided by persons at risk. This analysis aims to explain MDA coverage across time and geography in West Africa using sociological, environmental, and programmatic factors.

METHODOLOGY

The analysis links epidemiological coverage data from 3,880 LF MDAs with contextual, non-NTD data via location (each MDA was specific to a health district) and time (MDA month, year). Contextual data included rainfall, temperature, violence or social unrest, COVID-19, the 2014 Ebola outbreak, road access/isolation, population density, observance of Ramadan, and the number of previously completed MDAs.

PRINCIPAL FINDINGS

We fit a hierarchical linear regression model with coverage as the dependent variable and performed sensitivity analyses to confirm the selection of the explanatory factors. Above average rainfall, COVID-19, Ebola, violence and social unrest were all significantly associated with lower coverage. Years of prior experience in a district and above average temperature were significantly associated with higher coverage.

CONCLUSIONS/SIGNIFICANCE

These generalized and context-focused findings supplement current literature on coverage dynamics and MDA performance. Findings may be used to quantify typically anecdotal considerations in MDA planning. The model and methodology are offered as a tool for further investigation.

Accessing unproven interventions in the COVID-19 pandemic: discussion on the ethics of 'compassionate therapies' in times of catastrophic pandemics

Since the onset of the SARS-CoV-2 pandemic, an array of off-label interventions has been used to treat patients, either provided as compassionate care or tested in clinical trials. There is a challenge in determining the justification for conducting randomised controlled trials over providing compassionate use in an emergency setting. A rapid and more accurate evaluation tool is needed to assess the effect of these treatments. Given the similarity to the Ebola Virus Disease (EVD) pandemic in Africa in 2014, we suggest using a tool designed by the WHO committee in the aftermath of the EVD pandemic: Monitored Emergency Use of Unregistered and Investigational Interventions (MEURI). Considering the uncertainty around SARS-CoV-2, we propose using an improved MEURI including the Plan-Do-Study-Act tool. This combined tool may facilitate dynamic monitoring, analysing, re-evaluating and re-authorising emergency use of unproven treatments and repeat it in cycles. It will enable adjustment and application of outcomes to clinical practice according to changing circumstances and increase the production of valuable data to promote the best standard of care and high-quality research-even during a pandemic.

Translational pharmacokinetics of a novel bispecific antibody against Ebola virus (MBS77E) from animal to human by PBPK modeling & simulation

The goal of this study was to construct a PBPK model to accelerate the translation of MBS77E, a humanized bispecific antibody against the Ebola virus. In-depth nonclinical pharmacokinetic studies in rats, monkeys, wild-type mice and transgenic mice were conducted. The pH-dependent affinities (K_D) of MBS77E to recombinant FcRn of different species were determined by surface plasmon resonance analysis. A mechanistic whole-body PBPK model of MBS77E was developed and validated in the assessment of PK profiles and tissue distributions in preclinical models. This PBPK model was finally used to predict human PK behaviors of MBS77E. Simulations from the PBPK model with measured and fitted parameters were able to yield good predictions of the serum and tissue pharmacokinetic parameters of MBS77E within 2-fold errors. The predicted serum concentration in humans was able to maintain a sufficiently high level for more than 14 days after 50 mg/kg i.v. administrating. This achievement unlocks that PBPK modeling is a powerful tool to gain insights into the properties of antibody drugs. It guided experimental efforts to obtain necessary information before entry into humans.

Pyronaridine Protects against SARS-CoV-2 Infection in Mouse

There are currently relatively few small-molecule antiviral drugs that are either approved or emergency-approved for use against severe acute respiratory coronavirus 2 (SARS-CoV-2). One of these is remdesivir, which was originally repurposed from its use against Ebola. We evaluated three molecules we had previously identified computationally with antiviral activity against Ebola and Marburg and identified pyronaridine, which inhibited the SARS-CoV-2 replication in A549-ACE2 cells. The in vivo efficacy of pyronaridine has now been assessed in a K18-hACE transgenic mouse model of COVID-19. Pyronaridine treatment demonstrated a statistically significant reduction of viral load in the lungs of SARS-CoV-2-infected mice, reducing lung pathology, which was also associated with significant reduction in the levels of pro-inflammatory cytokines/chemokine and cell infiltration. Pyronaridine inhibited the viral PLpro activity in vitro (IC50 of 1.8 μM) without any effect on Mpro, indicating a possible molecular mechanism involved in its ability to inhibit SARS-CoV-2 replication. We have also generated several pyronaridine analogs to assist in understanding the structure activity relationship for PLpro inhibition. Our results indicate that pyronaridine is a potential therapeutic candidate for COVID-19.

Topological and Multivalent Effects in Glycofullerene Oligomers as EBOLA Virus Inhibitors

The synthesis of new biocompatible antiviral materials to fight against the development of multidrug resistance is being widely explored. Due to their unique globular structure and excellent properties, [60]fullerene-based antivirals are very promising bioconjugates. In this work, fullerene derivatives with different topologies and number of glycofullerene units were synthesized by using a SPAAC copper free strategy. This procedure allowed the synthesis of compounds 1–3, containing from 20 to 40 mannose units, in a very efficient manner and in short reaction times under MW irradiation. The glycoderivatives were studied in an infection assay by a pseudotyped viral particle with Ebola virus GP1. The results obtained show that these glycofullerene oligomers are efficient inhibitors of EBOV infection with IC₅₀s in the nanomolar range. In particular, compound 3, with four glycofullerene moieties, presents an outstanding relative inhibitory potency (RIP). We propose that this high RIP value stems from the appropriate topological features that efficiently interact with DC-SIGN.

Ebola Entry Inhibitors Discovered from Maesa perlarius

Ebola virus disease (EVD), a disease caused by infection with Ebola virus (EBOV), is characterized by hemorrhagic fever and a high case fatality rate. With limited options for the treatment of EVD, anti-Ebola viral therapeutics need to be urgently developed. In this study, over 500 extracts of medicinal plants collected in the Lingnan region were tested against infection with Ebola-virus-pseudotyped particles (EBOVpp), leading to the discovery of Maesa perlarius as an anti-EBOV plant lead. The methanol extract (MPBE) of the stems of this plant showed an inhibitory effect against EBOVpp, with an IC₅₀ value of 0.52 µg/mL, which was confirmed by testing the extract against infectious EBOV in a biosafety level 4 laboratory. The bioassay-guided fractionation of MPBE resulted in three proanthocyanidins (procyanidin B2 (1), procyanidin C1 (2), and epicatechin-(4β→8)-epicatechin-(4β→8)-epicatechin-(4β→8)-epicatechin (3)), along with two flavan-3-ols ((+)-catechin (4) and (−)-epicatechin (5)). The IC₅₀ values of the compounds against pseudovirion-bearing EBOV-GP ranged from 0.83 to 36.0 µM, with 1 as the most potent inhibitor. The anti-EBOV activities of five synthetic derivatives together with six commercially available analogues, including EGCG ((−)-epigallocatechin-3-O-gallate (8)), were further investigated. Molecular docking analysis and binding affinity measurement suggested the EBOV glycoprotein could be a potential molecular target for 1 and its related compounds.

Association between oral antimalarial medication administration and mortality among patients with Ebola virus disease: a multisite cohort study

BACKGROUND

Empiric antimalarial treatment is a component of protocol-based management of Ebola virus disease (EVD), yet this approach has limited clinical evidence for patient-centered benefits.

METHODS

This retrospective cohort study evaluated the association between antimalarial treatment and mortality among patients with confirmed EVD. The data was collected from five International Medical Corps operated Ebola Treatment Units (ETUs) in Sierra Leone and Liberia from 2014 through 2015. The standardized protocol used for patient care included empiric oral treatment with combination artemether and lumefantrine, twice daily for three days; however, only a subset of patients received treatment due to resource variability. The outcome of interest was mortality, comparing patients treated with oral antimalarials within 48-h of admission to those not treated. Analysis was conducted with logistic regression to generate adjusted odds ratios (aORs). Multivariable analyses controlled for ETU country, malaria rapid diagnostic test result, age, EVD cycle threshold value, symptoms of bleeding, diarrhea, dysphagia and dyspnea, and additional standard clinical treatments.

RESULTS

Among the 424 cases analyzed, 376 (88.7%) received early oral antimalarials. Across all cases, mortality occurred in 57.5% (244). In comparing unadjusted mortality prevalence, early antimalarial treated cases yielded 55.1% mortality versus 77.1% mortality for those untreated (p = 0.005). Multivariable analysis demonstrated evidence of reduced aOR for mortality with early oral antimalarial treatment versus non-treatment (aOR = 0.34, 95% Confidence Interval: 0.12, 0.92, p = 0.039).

CONCLUSION

Early oral antimalarial treatment in an EVD outbreak was associated with reduced mortality. Further study is warranted to investigate this association between early oral antimalarial treatment and mortality in EVD patients.

Structural Biology Illuminates Molecular Determinants of Broad Ebolavirus Neutralization by Human Antibodies for Pan-Ebolavirus Therapeutic Development

Monoclonal antibodies (mAbs) have proven effective for the treatment of ebolavirus infection in humans, with two mAb-based drugs Inmazeb™ and Ebanga™ receiving FDA approval in 2020. While these drugs represent a major advance in the field of filoviral therapeutics, they are composed of antibodies with single-species specificity for Zaire ebolavirus. The Ebolavirus genus includes five additional species, two of which, Bundibugyo ebolavirus and Sudan ebolavirus, have caused severe disease and significant outbreaks in the past. There are several recently identified broadly neutralizing ebolavirus antibodies, including some in the clinical development pipeline, that have demonstrated broad protection in preclinical studies. In this review, we describe how structural biology has illuminated the molecular basis of broad ebolavirus neutralization, including details of common antigenic sites of vulnerability on the glycoprotein surface. We begin with a discussion outlining the history of monoclonal antibody therapeutics for ebolaviruses, with an emphasis on how structural biology has contributed to these efforts. Next, we highlight key structural studies that have advanced our understanding of ebolavirus glycoprotein structures and mechanisms of antibody-mediated neutralization. Finally, we offer examples of how structural biology has contributed to advances in anti-viral medicines and discuss what opportunities the future holds, including rationally designed next-generation therapeutics with increased potency, breadth, and specificity against ebolaviruses.

Characterization of the therapeutic effect of antibodies targeting the Ebola glycoprotein using a novel BSL2-compliant rVSVΔG-EBOV-GP infection model

Ebola virus (EBOV) infections cause haemorrhagic fever, multi-organ failure and death, and survivors can experience neurological sequelae. Licensing of monoclonal antibodies targeting EBOV glycoprotein (EBOV-GP) improved its prognosis, however, this treatment is primarily effective during early stages of disease and its effectiveness in reducing neurological sequela remains unknown. Currently, the need for BSL4 containment hinders research and therapeutic development; development of an accessible BSL-2 in vivo mouse model would facilitate preclinical studies to screen and select therapeutics. Previously, we have shown that a subcutaneous inoculation with replicating EBOV-GP pseudotyped vesicular stomatitis virus (rVSVΔG-EBOV-GP or VSV-EBOV) in neonatal mice causes transient viremia and infection of the mid and posterior brain resulting in overt neurological symptoms and death. Here, we demonstrate that the model can be used to test therapeutics that target the EBOV-GP, by using an anti-EBOV-GP therapeutic (SAB-139) previously shown to block EBOV infection in mice and primates. We show that SAB-139 treatment decreases the severity of neurological symptoms and improves survival when administered before (1 day prior to infection) or up to 3 dpi, by which time animals have high virus titres in their brains. Improved survival was associated with reduced viral titres, microglia loss, cellular infiltration/activation, and inflammatory responses in the brain. Interestingly, SAB-139 treatment significantly reduced the severe VSV-EBOV-induced long-term neurological sequalae although convalescent mice showed modest evidence of abnormal fear responses. Together, these data suggest that the neonatal VSV-EBOV infection system can be used to facilitate assessment of therapeutics targeting EBOV-GP in the preclinical setting.

A computational overview on phylogenetic characterization, pathogenic mutations, and drug targets for Ebola virus disease

The World Health Organization declared Ebola virus disease (EVD) as the major outbreak in the 20th century. EVD was first identified in 1976 in South Sudan and the Democratic Republic of the Congo. EVD was transmitted from infected fruit bats to humans via contact with infected animal body fluids. The Ebola virus (EBOV) has a genome size of ∼18,959 bp. It encodes seven distinct proteins: nucleoprotein (NP), glycoprotein (GP), viral proteins VP24, VP30, VP35, matrix protein VP40, and polymerase L is considered a prime target for potential antiviral strategies. The current US FDA-approved anti-EVD vaccine, ERVERBO, and the other equally effective anti-EBOV combinations of three fully human monoclonal antibodies such as REGN-EB3, primarily target the envelope glycoprotein. This work elaborates on the EBOV's phylogenetic structure and the crucial mutations associated with viral pathogenicity.

COVID-19, Ebola virus disease, and Nipah virus infection reclassification as novel acute immune dysrhythmia syndrome (n-AIDS): potential crucial role for immunomodulators

In this manuscript, COVID-19, Ebola virus disease, Nipah virus infection, SARS, and MERS are suggested to be considered for a novel immunological reclassification as acute onset immune dysrhythmia syndrome (n-AIDS) due to altered monocytic, Th1/Th2, as well as cytokines and chemokines balances. n-AIDs is postulated to be the cause of the acute respiratory distress and multi-inflammatory syndromes which are described with fatal COVID-19, and immunomodulators are suggested to effectively manage the mentioned diseases as well as for other disorders caused by Th1/Th2 imbalance. Meanwhile, para COVID syndrome is suggested to describe various immune-related complications, whether before or after recovery, and to embrace a potential of a latent infection, that might be discovered later, as occurred with Ebola virus disease. Finally, our hypothesis has evolved out of our real-life practice that uses immunomodulatory drugs to manage COVID-19 safely and effectively.

Genome structure and genetic diversity in the Ebola virus

Ebola is a deadly pathogen responsible for Ebola virus disease, first came to prominence in the year 1976. This rapidly evolving virus imposed a serious threat to the human population in the last few decades and also continues to be a probable threat to our race. A better understanding of the virus in terms of its genomic structure is very much needed to develop an effective antiviral therapy against this deadly pathogen. Complete knowledge of its genomic structure and variations will help us and the entire scientific community to design effective therapy in terms of either vaccine development or the development of proper antiviral medicine.

STAT-1 Knockout Mice as a Model for Wild-Type Sudan Virus (SUDV)

Currently there is no FDA-licensed vaccine or therapeutic against Sudan ebolavirus (SUDV) infections. The largest ever reported 2014–2016 West Africa outbreak, as well as the 2021 outbreak in the Democratic Republic of Congo, highlight the critical need for countermeasures against filovirus infections. A well-characterized small animal model that is susceptible to wild-type filoviruses would greatly add to the screening of antivirals and vaccines. Here, we infected signal transducer and activator of transcription-1 knock out (STAT-1 KO) mice with five different wildtype filoviruses to determine susceptibility. SUDV and Marburg virus (MARV) were the most virulent, and caused 100% or 80% lethality, respectively. Zaire ebolavirus (EBOV), Bundibugyo ebolavirus (BDBV), and Taï Forest ebolavirus (TAFV) caused 40%, 20%, and no mortality, respectively. Further characterization of SUDV in STAT-1 KO mice demonstrated lethality down to 3.1 × 10¹ pfu. Viral genomic material was detectable in serum as early as 1 to 2 days post-challenge. The onset of viremia was closely followed by significant changes in total white blood cells and proportion of neutrophils and lymphocytes, as well as by an influx of neutrophils in the liver and spleen. Concomitant significant fluctuations in blood glucose, albumin, globulin, and alanine aminotransferase were also noted, altogether consistent with other models of filovirus infection. Finally, favipiravir treatment fully protected STAT-1 KO mice from lethal SUDV challenge, suggesting that this may be an appropriate small animal model to screen anti-SUDV countermeasures.

DrugComb update: a more comprehensive drug sensitivity data repository and analysis portal

Combinatorial therapies that target multiple pathways have shown great promises for treating complex diseases. DrugComb (https://drugcomb.org/) is a web-based portal for the deposition and analysis of drug combination screening datasets. Since its first release, DrugComb has received continuous updates on the coverage of data resources, as well as on the functionality of the web server to improve the analysis, visualization and interpretation of drug combination screens. Here, we report significant updates of DrugComb, including: (i) manual curation and harmonization of more comprehensive drug combination and monotherapy screening data, not only for cancers but also for other diseases such as malaria and COVID-19; (ii) enhanced algorithms for assessing the sensitivity and synergy of drug combinations; (iii) network modelling tools to visualize the mechanisms of action of drugs or drug combinations for a given cancer sample and (iv) state-of-the-art machine learning models to predict drug combination sensitivity and synergy. These improvements have been provided with more user-friendly graphical interface and faster database infrastructure, which make DrugComb the most comprehensive web-based resources for the study of drug sensitivities for multiple diseases.