Search

Ebola outbreak in eastern parts of the Democratic Republic of the Congo in 2018–2020 proved that the virus remains highly hazardous for humans, and the outbreak in West Africa in 2014–2016, which was the largest Ebola outbreak in history, showed that it could be imported to other continents, including Russia. In 1993 the Federal State Budgetary Institution “48th Central Scientific Research Institute” of the Russian Ministry of Defence developed a specific equine immunoglobulin for emergency prophylaxis of Ebola in risk groups. The evaluation and improvement of the product’s properties is an important area in the development of biological defence technologies.The aim of the studywas to examine the properties of the equine anti-Ebola immunoglobulin which had been stored for a long time at 2–8 °C.Materials and methods:the authors studied batches of heterologous anti-Ebola immunoglobulin that had been stored for 17–22 years. The properties of the product were evaluated according to the requirements of the State Pharmacopoeia of the Russian Federation, 14th ed. (Ph. Rus. 14 ed.). The specific activity of the product was determined in a plaque reduction neutralisation test using Ebola virus and African green monkey kidney cells (GMK-AH-1(D)). Immunoglobulin molecular parameters were determined by size-exclusion high-performance liquid chromatography using the test methods described in the European Pharmacopoeia 9.6 and Ph. Rus. 14 ed.Results:the storage of anti-Ebola immunoglobulin for 17–22 years at 2–8 °C resulted in a four-fold reduction of the level of virus-neutralising antibodies against Ebola, decrease in the proportion of monomers from 98 to 74–90%, increase in the proportion of dimers and polymers, and formation of immunoglobulin molecules’ fragments. Signs of toxicity for mice were observed in one of the three product batches.Conclusions:the obtained results suggest the need to perform more studies to test the quality of antiEbola immunoglobulin batches that were stored for shorter periods of time in order to assess the stability of their initial characteristics.

Introduction. The outbreaks of the Zaire ebolavirus (ZE) disease (ZED) that have arisen in the last decade determine the need to study the infection pathogenesis, the formation of specific immunity forming as well as the development of effective preventive and therapeutic means. All stages of fight against the ZED spread require the experimental infection in sensitive laboratory animals, which are rhesus monkeys in case of this disease . The aim of the study is to evaluate the rhesus monkey cellular immunity following the ZE experimental infection by the means of flow cytometry (cytofluorimetry). Material and methods. Male rhesus monkeys were intramuscularly infected by the dose of 15 LD50 (dose of the pathogen that causes 50% mortality of infected animals) of the ZE, the Zaire strain (ZEBOV). Levels of 18 peripheral blood lymphocyte populations of the animals before the ZE experimental infection and at the terminal stage of the disease were assessed using flow cytometry. Results and discussion. The certain changes in the levels of the lymphocyte populations were observed following infection, indicating simultaneous activation and suppression of the immune system during ZED. The increase in content was observed for T-lymphocytes, T-helper and cytotoxic T-lymphocytes expressing the corresponding markers of early activation. The decrease was recorded for T-lymphocytes and double-positive T-lymphocytes expressing corresponding markers of late activation, as well as natural killer cells expressing CD8 (p < 0.05). Conclusion. For the first time in the Russian Federation, the rhesus monkey cellular immunity before and after the ZE experimental infection was assessed using flow cytometry.

The Ebola virus disease (EVD) is one of the most dangerous infections affecting humans and animals. The first EVD outbreaks occurred in 1976 in Sudan and Zaire. Since then, more than 20 outbreaks have occurred; the largest of which (2014-2016) evolved into an epidemic in West Africa and claimed the lives of more than 11,000 people. Although vaccination is the most effective way to prevent epidemics, there was no licensed vaccine for EVD at the beginning of the latest outbreak. The development of the first vaccines for EVD started in 1980 and has come a long technological way, from inactivated to genetically engineered vaccines based on recombinant viral vectors. This review focuses on virus-vectored Ebola vaccines that have demonstrated the greatest efficacy in preclinical trials and are currently under different phases of clinical trial. Particular attention is paid to the mechanisms of immune response development, which are important for protection from EVD, and the key vaccine parameters necessary for inducing long-term protective immunity against EVD.

Ebola hemorrhagic fever, also known as Ebola virus disease or EVD, is one of the most dangerous viral diseases in humans and animals. In this open-label, dose-escalation clinical trial, we assessed the safety, side effects, and immunogenicity of a novel, heterologous prime-boost vaccine against Ebola, which was administered in 2 doses to 84 healthy adults of both sexes between 18 and 55 years. The vaccine consists of live-attenuated recombinant vesicular stomatitis virus (VSV) and adenovirus serotype-5 (Ad5) expressing Ebola envelope glycoprotein. The most common adverse event was pain at the injection site, although no serious adverse events were reported. The vaccine did not significantly impact blood, urine, and immune indices. Seroconversion rate was 100 %. Antigen-specific IgG geometric mean titer at day 42 was 3,277 (95 % confidence interval 2,401–4,473) in volunteers immunized at full dose. Neutralizing antibodies were detected in 93.1 % of volunteers immunized at full dose, with geometric mean titer 20. Antigen-specific response in peripheral blood mononuclear cells was also detected in 100 % of participants, as well as in CD4+ and CD8+ T cells in 82.8 % and 58.6 % of participants vaccinated at full dose, respectively. The data indicate that the vaccine is safe and induces strong humoral and cellular immune response in up to 100 % of healthy adult volunteers, and provide a rationale for testing efficacy in Phase III trials. Indeed, the strong immune response to the vaccine may elicit long-term protection. This trial was registered with grls.rosminzdrav.ru (No. 495*), and with zakupki.gov.ru (No. 0373100043215000055).

Ebola virus, representative of the Ebolavirus genus, Filoviridae family, causes severe hemorrhagic fever in humans, with lethality rates amounting up to 90 %. The members of Ebolavirus genus infect a broad range of mammalian cells. Recent studies indicate that entry of Ebola virus into cells requires a series of cellular protein interactions and molecular mechanisms, some of which are unique to filoviruses, while others are commonly used by all viral glycoproteins. The cellular factors deployed by filoviruses for their entry into permissive cells are defined incompletely. The aim of this review is to analyze peculiarity of the Ebola virus penetration into permissive cells at molecular level. The Ebola virus entry into cells is initiated by the interaction of viral glycoprotein with one or more receptors on the surface of host-cell. The main host-cell factors, involved in filovirus entry, are: attachment factors (cell lectins and human T-cell mucin 1 (TIM-1)), signaling factors (tyrosinkinase receptors and α 5 β 1 -integrin), and endolisosomal host-cell factors (cathepsins B and L and Niemann-Pick C1 protein. The study of the complex set of virus entry events provides potential avenues for the development of antiviral therapies against Ebola fever.