Development of Pan-filovirus vaccine against Ebola and Marburg virus challenges

Filoviruses such as Ebola (EBOV) and Marburg (MARV) viruses cause deadly viral hemorrhagic fever in humans with high case fatality rates. To date, no licenced therapeutic or vaccine has been clinically approved to prevent infection. Several vaccine candidates are under development against the few most common filoviruses targeting the virus glycoprotein (GP). However, protective antibodies induced by such GP vaccines are usually limited to the same species. In contrast, T-cell vaccines offer an opportunity to design a single pan-filovirus vaccine protecting against all members of the Filoviridae family. In this study FILOcepX vaccines were constructed targeting the four most conserved regions among the viral proteomes with the aim to induce protective T-cell responses against different filoviruses. BALB/c mice were immunized with FILOcep 1 and 2 vaccines vectored by non-replicating engineered simian adenovirus and poxvirus MVA. Groups of 20 BALB/c mice were primed and boosted with either the FILOcep1 and FILOcep2 vaccines or control ChAdOx1- and MVA-vectored vaccines. Four animals in each group were sacrificed after 1 week of boosting to detect T-cell response for the FILOcepX antigen. High frequency T cells specific responses were detected in mice receiving the test vaccines by IFN-γ ELISPOT kits. Of the remaining 16 animals in each group, 8 were challenged with mouse-adapted EBOV and 8 were challenged with mouse adapted MARV in Containment Level 4 laboratory. All the mice in the control group either died or had to be euthanized between 4 and 6 days post challenge. On the other hand all the FILOcepX vaccinated mice maintained their normal body mass and survived till the end of the scheduled protocol on day 29 post challenge. These FILOcepX vaccines provided 100% protection against the lethal challenges with filoviruses of two different genera. Further evaluation the efficacy of this vaccine in non-human primates (NHPs) is warranted

Ebola viral load at diagnosis associates with patient outcome and outbreak evolution

BACKGROUND. Ebola virus (EBOV) causes periodic outbreaks of life-threatening EBOV disease in Africa. Historically, these outbreaks have been relatively small and geographically contained; however, the magnitude of the EBOV outbreak that began in 2014 in West Africa has been unprecedented. The aim of this study was to describe the viral kinetics of EBOV during this outbreak and identify factors that contribute to outbreak progression. METHODS. From July to December 2014, one laboratory in Sierra Leone processed over 2,700 patient samples for EBOV detection by quantitative PCR (qPCR). Viremia was measured following patient admission. Age, sex, and approximate time of symptom onset were also recorded for each patient. The data was analyzed using various mathematical models to find trends of potential interest. RESULTS. The analysis revealed a significant difference (P = 2.7 × 10–77) between the initial viremia of survivors (4.02 log10 genome equivalents [GEQ]/ml) and nonsurvivors (6.18 log10 GEQ/ml). At the population level, patient viral loads were higher on average in July than in November, even when accounting for outcome and time since onset of symptoms. This decrease in viral loads temporally correlated with an increase in circulating EBOV-specific IgG antibodies among individuals who were suspected of being infected but shown to be negative for the virus by PCR. CONCLUSIONS. Our results indicate that initial viremia is associated with outcome of the individual and outbreak duration; therefore, care must be taken in planning clinical trials and interventions. Additional research in virus adaptation and the impacts of host factors on EBOV transmission and pathogenesis is needed

Linked Mutations in the Ebola Virus Polymerase Are Associated with Organ Specific Phenotypes

Ebola virus (EBOV) causes a severe infection called Ebola virus disease (EVD). The pathogenesis of EBOV infection is complex, and outcome has been associated with a variety of immunological and cellular factors. Disease can result from several mechanisms, including direct organ and endothelial cell damage as a result of viral replication. During the2013 to 2016 Western Africa EBOV outbreak, several mutants emerged, with changes in the genes of nucleoprotein (NP), glycoprotein (GP), and the large (L) protein. Reverse genetic analysis has been used to investigate whether these mutations played any role in pathogenesis with mixed results depending on the experimental system used. Previous studies investigated the impact of three single nonsynonymous mutations (GP-A82V, NP-R111C, and L-D759G) on the fatality rate of mouse and ferret models and suggested that the L-D759G mutation decreased the virulence of EBOV. In this study, the effect of these three mutations was further evaluated by deep sequencing to determine viral population genetics and the host response in longitudinal samples of blood, liver, kidney, spleen, and lung tissues taken from the previous ferret model. The data indicated that the mutations were maintained in the different tissues, but the frequency of minor genomic mutations were different. In addition, compared to wild-type virus, the recombinant mutants had different within host effects, where the D759G (and accompanying Q986H) substitution in the L protein resulted in an upregulation of the immune response in the kidney, liver, spleen, and lungs. Together these studies provide insights into the biology of EBOV mutants both between and within hosts. IMPORTANCE Ebola virus infection can have dramatic effects on the human body which manifest in Ebola virus disease. The outcome of infection is either survival or death and in the former group with the potential of longer-term health consequences and persistent infection. Disease severity is undoubtedly associated with the host response, often with overt inflammatory responses correlated with poorer outcomes. The scale of the2013 to 2016 Western African Ebola virus outbreak revealed new aspects of viral biology. This included the emergence of mutants with potentially altered virulence. Biobanked tissue from ferret models of EBOV infected with different mutants that emerged in the Western Africa outbreak was used to investigate the effect of EBOV genomic variation in different tissues. Overall, the work provided insights into the population genetics of EBOV and showed that different organs in an animal model can respond differently to variants of EBOV

Development of a Human Antibody Cocktail that Deploys Multiple Functions to Confer Pan-Ebolavirus Protection.

Passive administration of monoclonal antibodies (mAbs) is a promising therapeutic approach for Ebola virus disease (EVD). However, all mAbs and mAb cocktails that have entered clinical development are specific for a single member of the Ebolavirus genus, Ebola virus (EBOV), and ineffective against outbreak-causing Bundibugyo virus (BDBV) and Sudan virus (SUDV). Here, we advance MBP134, a cocktail of two broadly neutralizing human mAbs, ADI-15878 from an EVD survivor and ADI-23774 from the same survivor but specificity-matured for SUDV GP binding affinity, as a candidate pan-ebolavirus therapeutic. MBP134 potently neutralized all ebolaviruses and demonstrated greater protective efficacy than ADI-15878 alone in EBOV-challenged guinea pigs. A second-generation cocktail, MBP134AF, engineered to effectively harness natural killer (NK) cells afforded additional improvement relative to its precursor in protective efficacy against EBOV and SUDV in guinea pigs. MBP134AF is an optimized mAb cocktail suitable for evaluation as a pan-ebolavirus therapeutic in nonhuman primates

Ebola GP-Specific Monoclonal Antibodies Protect Mice and Guinea Pigs from Lethal Ebola Virus Infection

Ebola virus (EBOV) causes acute hemorrhagic fever in humans and non-human primates with mortality rates up to 90%. So far there are no effective treatments available. This study evaluates the protective efficacy of 8 monoclonal antibodies (MAbs) against Ebola glycoprotein in mice and guinea pigs. Immunocompetent mice or guinea pigs were given MAbs i.p. in various doses individually or as pools of 3–4 MAbs to test their protection against a lethal challenge with mouse- or guinea pig-adapted EBOV. Each of the 8 MAbs (100 µg) protected mice from a lethal EBOV challenge when administered 1 day before or after challenge. Seven MAbs were effective 2 days post-infection (dpi), with 1 MAb demonstrating partial protection 3 dpi. In the guinea pigs each MAb showed partial protection at 1 dpi, however the mean time to death was significantly prolonged compared to the control group. Moreover, treatment with pools of 3–4 MAbs completely protected the majority of animals, while administration at 2–3 dpi achieved 50–100% protection. This data suggests that the MAbs generated are capable of protecting both animal species against lethal Ebola virus challenge. These results indicate that MAbs particularly when used as an oligoclonal set are a potential therapeutic for post-exposure treatment of EBOV infection

Mucosal Immunization of Cynomolgus Macaques with the VSVΔG/ZEBOVGP Vaccine Stimulates Strong Ebola GP-Specific Immune Responses

(ZEBOV) produces a lethal viral hemorrhagic fever in humans and non-human primates.We demonstrate that the VSVΔG/ZEBOVGP vaccine given 28 days pre-challenge either intranasally (IN), orally (OR), or intramuscularly (IM) protects non-human primates against a lethal systemic challenge of ZEBOV, and induces cellular and humoral immune responses. We demonstrated that ZEBOVGP-specific T-cell and humoral responses induced in the IN and OR groups, following an immunization and challenge, produced the most IFN-γ and IL-2 secreting cells, and long term memory responses.We have shown conclusively that mucosal immunization can protect from systemic ZEBOV challenge and that mucosal delivery, particularly IN immunization, seems to be more potent than IM injection in the immune parameters we have tested. Mucosal immunization would be a huge benefit in any emergency mass vaccination campaign during a natural outbreak, or following intentional release, or for mucosal immunization of great apes in the wild

Funding vaccines for emerging infectious diseases

Immunization has played a large role in substantially reducing the infected and death tolls from infectious diseases. In the case of emerging diseases, the identity of the pathogen responsible, as well as the time and location for the next outbreak, cannot be accurately predicted using current means. Coupled with disjointed efforts towards the development of vaccines and a lack of funds and desire to advance promising products against known emerging pathogens to clinical trials, there has been a shortage of approved products ready for emergency use. Recent outbreaks have exposed these weaknesses, and the Coalition for Epidemic Preparedness Innovations (CEPI) was created in 2016 to address these issues. In this commentary, we discuss the establishment of such a global vaccine fund, and provide some additional points to consider for stimulating further discussion on this comprehensive, ambitious initiative

Structural Response of a Prefabricated Utility Tunnel Subject to a Reverse Fault

Prefabricated utility tunnels have drawn much attention in relation to rapid urban development. On this, how to maintain the integrity of an underground lifeline, which is subjected to unexpected fault displacement action, is a concern either from the design or the construction aspect. By applying the commercial software program ABAQUS, this paper presents a systematic numerical simulation of a prefabricated utility tunnel affected by a reverse fault. The critical parameters investigated in this study include fault displacement, burial depth, utility tunnel-soil friction coefficient, and the angle of the utility tunnel crossing the fault plane. Results of the numerical modeling revealed that: (1) both the overall structural deformation and the spliced joints deformation of the prefabricated utility tunnel increase with increasing fault displacement, which greatly reduces the waterproofing ability of the utility tunnel joints; (2) the opening displacement of the joints on the roof of the utility tunnel near the fault plane is positively correlated with burial depth, but the variation is slight; (3) the variations in utility tunnel-soil friction coefficient have little effect on the overall structural deformation and the spliced joints deformation; (4) the opening displacement of the spliced joints of the utility tunnel basically gradually increases with an increase in the crossing angle near the fault plane, which is different than when it is away from the fault plane. The main outcomes obtained from this study can provide reference for the construction of prefabricated utility tunnel in fault active area