Biology subjects

Gushchin, V. A.

Publications and source records attributed to Gushchin, V. A..

10 recordsLinked to original sources

bioRxiv2025

Characterization of a lethal Crimean-Congo hemorrhagic fever virus infection model in interferon-deficient mice for studies of virus pathogenicity and vaccine efficacy

Crimean-Congo hemorrhagic fever virus (CCHFV) is a highly pathogenic tick-borne virus causing severe human disease and representing a significant public health threat. The absence of licensed vaccines and specific antiviral therapies highlights the need for well-characterized experimental models suitable for studying viral pathogenicity and evaluating medical countermeasures. In this study, we established and characterized an integrated in vitro and in vivo platform for CCHFV research. Virus propagation was optimized by comparing Vero E6 and SW-13 cell lines. SW-13 cells supported efficient CCHFV replication resulting in pronounced virus-induced cytopathic effects, whereas no detectable cytopathic effects were observed in Vero E6 cells. Virus titers determined by cytopathic effect based endpoint dilution and antigen ELISA coincided, supporting the use of SW-13 cells for virus stock preparation. Using virus stocks generated in SW-13 cells, interferon-deficient mice were infected with different doses of CCHFV to assess dose-dependent pathogenicity. Infection resulted in severe disease and high mortality across all tested doses. Based on survival analysis, a dose of 10 TCID50 was selected for further characterization, which revealed progressive weight loss and high viral loads in peripheral organs. Overall, this study establishes a robust IFN knockout mouse model suitable for studying CCHFV pathogenicity, comparing viral genovariants, and evaluating vaccines, antiviral compounds, and neutralizing antibodies.

microbiology↗

bioRxiv2025

Circular mRNA against Clean Cap linear mRNA vectors comprehensive comparison, expression, active and passive immunization

The mRNA platform has revolutionised vaccine technology by providing a universal, fast and easily scalable production process. There are two main types of mRNA - linear (cap-dependent) and circular (cap-independent), each with its own advantages. Although both vector types are continuously being improved, there has been no comprehensive comparative analysis of the most efficient existing vectors of each type. This paper provides a comparison of expression efficiency, protective and therapeutic activities of circular and linear mRNA vectors. We examined different combinations of linear vectors: containing either N1-methylpseudouridines or uridine and capped with either ARCA (m7G(5')ppp(5')G) or CleanCap (m7G(5')ppp(5')m2G). Circular vectors contained both commonly used IRES of coxsackievirus B3 and new a IRES of human rhinoviruses B6. Preliminary luciferase assay showed that modified linear vectors exhibited significantly higher expression levels both in vitro and in vivo. A similar but less dramatic difference was observed in expression of the target protein. At the same time, immunogenicity and protective activity of linear and circular vectors were equal.

immunology↗

bioRxiv2025

Comparison candidate Tick-borne encephalitis virus vaccines based on mRNA, adenovirus serotype 25 and chimera of YFV vaccine strain

BackgroundDespite the availability of several licensed inactivated vaccines, the development of new vaccines against the Tick-borne encephalitis virus (TBEV) remains an important task, especially in countries endemic to this pathogen. The risk of infection with TBEV increases every year because of increase in the number of ticks, the emergence of tick carriers into new territories, and active human activity in areas of TBEV natural foci. Annual reports of vaccination failures have prompted us to search for approaches to creating a new vaccine. ObjectivesIn our study, we used the same PrM and E antigens to produce three vaccine candidates against tick-borne encephalitis (TBE): 1) a live attenuated YFV 17DD-UN vaccine strain, 2) recombinant adenovirus (rAd) vectors, and 3) mRNA encapsulated in lipid nanoparticles (LNP). MethodsWe generated and assessed the immunogenicity and protective efficacy of three candidate TBEV vaccines based on mRNA, simian adenovirus type 25, and a chimera of the YFV 17DD-UN attenuated strain. ResultsAnalysis of the virus-neutralizing titers in the blood sera of immunized mice revealed a statistically significant difference among the three candidate vaccines. The immunogenicity and protective efficacy of the candidate mRNA-LNP vaccine were found to be higher than those of the other two vaccines. ConclusionsBased on the results of our study, it can be concluded that the mRNA-based platform is more promising for the creation of a vaccine against TBEV.

immunology↗

bioRxiv2024

Major role of S-glycoprotein in providing immunogenicity and protective immunity in mRNA lipid nanoparticle vaccines based on SARS-CoV-2 structural proteins

Recently we have developed an mRNA lipid nanoparticle (mRNA-LNP) platform providing efficient long-term expression of an encoded gene in vivo after both intramuscular and intravenous application. Based on this platform, we have generated mRNA-LNP coding SARS-CoV-2 structural proteins M, N, S from different virus variants and studied their immunogenicity separately or in combinations in vivo. As a result, all candidate vaccine compositions coding S and N proteins induced excellent anti-RBD and N titers of binding antibodies. T cell responses mainly represented specific CD4+ T cell lymphocyte producing IL-2 and TNF-. mRNA-LNP coding M protein did not show high immunogenicity. High neutralizing activity was detected in sera of mice vaccinated with mRNA-LNP coding S protein (alone or in combinations) against closely related strains but was not detectable or significantly lower against an evolutionarily distant variant. Our data showed that the addition of mRNAs encoding S and M antigens to the mRNA-N in the vaccine composition enhanced immunogenicity of mRNA-N inducing more robust immune response to the N protein. Based on our results, we suggested that the S protein plays a key role in enhancement of immune response to the N protein in the mRNA-LNP vaccine.

immunology↗

bioRxiv2023

Trivalent mRNA vaccine-candidate against seasonal flu with cross-specific humoral immune response

ABSTRACTSeasonal influenza remains a serious global health problem, leading to high mortality rates among the elderly and individuals with comorbidities. It also imposes a substantial economic burden through increased absenteeism during periods of active pathogen circulation. Vaccination is generally accepted as the most effective strategy for influenza prevention. As both influenza A and B viruses circulate and cause seasonal epidemics, vaccines need to include multiple antigens derived from different viral subtypes. While current influenza vaccines are effective, they still have limitations, including narrow specificity for certain serological variants, which may result in a mismatch between vaccine antigens and circulating strains. Additionally, the rapid variability of the virus poses challenges in providing extended protection beyond a single season. Therefore, mRNA technology is particularly promising for influenza prevention, as it enables the rapid development of multivalent vaccines and allows for quick updates of their antigenic composition. mRNA vaccines have already proven successful in preventing COVID-19 by eliciting rapid cellular and humoral immune responses. In this study, we present the development of a trivalent mRNA vaccine candidates, evaluate its immunogenicity using the hemagglutination inhibition assay, and assess its efficacy in animals. We demonstrate the higher immunogenicity of the mRNA vaccine candidates compared to the inactivated split influenza vaccine and its enhanced ability to generate a cross-specific humoral immune response. These findings highlight the potential mRNA technology in overcoming current limitations of influenza vaccines and hold promise for ensuring greater efficacy in preventing seasonal influenza outbreaks.

immunology↗

bioRxiv2023

Lethality of West Nile virus strains in a mouse model

West Nile fever (WNF) is a viral infection caused by West Nile virus (WNV), a flavivirus of the Flaviviridae family. Virus circulates between mosquitoes and wild birds, but can infect other species, including humans. The first cases of West Nile fever were reported in Africa in the 1930s. Currently, WNV has a wide geographic range, which includes countries in Europe, Asia, Africa, Australia, and North and South America, where it periodically causes WNF outbreaks. The disease in human occurs with the development of fever, and in some cases ending up severe neurological complications. Studies of the virus in animal models demonstrate that virulence varies depending on the host species, the genotype of the virus, and the presence of substitutions in key viral proteins, even within the same genotype. These studies highlight the need for comparative studies of different WNV strains to evaluate the impact of amino acid substitutions on WNV pathogenesis. Analysis of key mutations and substitutions will allow the development of a safe and effective vaccine for the prevention of WNF.

microbiology↗

bioRxiv2022

Single-domain antibody delivery using an mRNA platform protects against lethal doses of botulinum neurotoxin A

Single-domain antibodies (sdAbs, VHHs, or nanobodies) are a promising tool for the treatment of both infectious and somatic diseases. Their small size greatly simplifies any genetic engineering manipulations. Such antibodies have the ability to bind hard-to-reach antigenic epitopes through long parts of the variable chains, the third complementarity-determining regions (CDR3s). VHH fusion with the canonical immunoglobulin Fc fragment allows the Fc-fusion single-domain antibodies (VHH-Fc) to significantly increase their neutralizing activity and serum half-life. Previously we have developed and characterized VHH-Fc specific to botulinum neurotoxin A (BoNT/A), that showed a 1000-fold higher protective activity than monomeric form when challenged with five times the lethal dose (5 LD50) of BoNT/A. During the COVID-19 pandemic, mRNA vaccines based on lipid nanoparticles (LNP) as a delivery system have become an important translational technology that has significantly accelerated the clinical introduction of mRNA platforms. We have developed an mRNA platform that provides long-term expression after both intramuscular and intravenous application. The platform has been extensively characterized using firefly luciferase (Fluc) as a reporter. An intramuscular administration of LNP-mRNA encoding VHH-Fc antibody made it possible to achieve its rapid expression in mice and resulted in 100% protection when challenged with up to 100 LD50 of BoNT/A. The presented approach for the delivery of sdAbs using mRNA technology greatly simplifies drug development for antibody therapy and can be used for emergency prophylaxis.

molecular biology↗

bioRxiv2021

SARS-CoV-2 cell-to-cell infection is resistant to neutralizing antibodies

The COVID-19 pandemic caused by SARS-CoV-2 has posed a global threat to human lives and economics. One of the best ways to determine protection against the infection is to quantify the neutralizing activity of serum antibodies. Multiple assays have been developed to validate SARS-CoV-2 neutralization; most of them utilized lentiviral or vesicular stomatitis virus-based particles pseudotyped with the spike (S) protein, making them safe and acceptable to work with in many labs. However, these systems are only capable of measuring infection with purified particles. This study has developed a pseudoviral assay with replication-dependent reporter vectors that can accurately quantify the level of infection directly from the virus producing cell to the permissive target cell. Comparative analysis of cell-free and cell-to-cell infection revealed that the neutralizing activity of convalescent sera was more than tenfold lower in cell cocultures than in the cell-free mode of infection. As the pseudoviral system could not properly model the mechanisms of SARS-CoV-2 transmission, similar experiments were performed with replication-competent coronavirus, which detected nearly complete SARS-CoV-2 cell-to-cell infection resistance to neutralization by convalescent sera. Based on available studies, this is the first attempt to quantitatively measure SARS-CoV-2 cell-to-cell infection, for which the mechanisms are largely unknown. The findings suggest that this route of SARS-CoV-2 transmission could be of great importance for treatment and prevention of COVID-19. ImportanceImmune surveillance of viral or bacterial infections is largely mediated by neutralizing antibodies. Antibodies against the SARS-CoV-2 spike protein are produced after vaccination or infection, but their titers only partly reflect the degree of protection against infection. To identify protective antibodies, a neutralization test with replicating viruses or pseudoviruses (PVs) is required. This study developed lentiviral-based PV neutralization assays that, unlike similar systems reported earlier, enable quantitative measurement of SARS-CoV-2 neutralization in cell cocultures. Using both PVs and replication-competent virus, it was demonstrated that SARS-CoV-2 cell-to-cell infection is considerably more resistant to serum neutralization than infection with purified viral particles. The tests are easy to set up in many labs, and are believed to be more informative for monitoring SARS-CoV-2 collective immunity or entry inhibitor screening.

microbiology↗

bioRxiv2021

Snake venom phospholipases A2 possess a strong virucidal activity against SARS-CoV-2 in vitro and block the cell fusion mediated by spike glycoprotein interaction with the ACE2 receptor

A new coronavirus was recently discovered and named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In the absence of specific therapeutic and prophylactic agents, the virus has infected almost hundred million people, of whom nearly two million have died from the viral disease COVID-19. The ongoing COVID-19 pandemic is a global threat requiring new therapeutic strategies. Among them, antiviral studies based on natural molecules are a promising approach. The superfamily of phospholipases A2 (PLA2s) consists of a large number of members that catalyze the hydrolysis of phospholipids at a specific position. Here we show that secreted PLA2s from the venom of various snakes protect to varying degrees the Vero E6 cells widely used for the replication of viruses with evident cytopathic action, from SARS-CoV-2 infection PLA2s showed low cytotoxicity to Vero E6 cells and the high antiviral activity against SARS-CoV-2 with IC50 values ranged from 0.06 to 7.71 g/ml. Dimeric PLA2 HDP-2 from the viper Vipera nikolskii, as well as its catalytic and inhibitory subunits, had potent virucidal (neutralizing) activity against SARS-CoV-2. Inactivation of the enzymatic activity of the catalytic subunit of dimeric PLA2 led to a significant decrease in antiviral activity. In addition, dimeric PLA2 inhibited cell-cell fusion mediated by SARS-CoV-2 spike glycoprotein. These results suggest that snake PLA2s, in particular dimeric ones, are promising candidates for the development of antiviral drugs that target lipid bilayers of the viral envelope and may be good tools to study the interaction of viruses with host cell membranes.

microbiology↗

bioRxiv2019

Alongshan virus in Russia

In recent decades, many new flavi-like viruses have been discovered predominantly in different invertebrates and, as was recently shown, some of them may cause disease in humans. The Jingmen tick virus (JMTV) group holds a special place among flavi-like viruses because, in contrast to the "classic" flaviviruses and other flavi-like viruses, they have a segmented ssRNA(+) genome. Two segments of the JMTV genome have homology with regions of the flavivirus genome encoding polymerase and helicase-protease proteins. JMTVs have several open reading frames (ORF) in segments encoding glycoprotein(s) and capsid protein and these ORF are specific only to them. JMTVs greatly differ in virion size. We isolated three strains of Alongshan virus (ALSV), which is a representative of the JMTV group, from adult Ixodes persulcatus ticks collected in two geographically-separated Russian regions in the tick cell line IRE/CTVM19. One of the strains persisted in the IRE/CTVM19 cells without cytopathic effect for three years. Most virions purified from tick cells were spherical with a diameter of approximately 40.5 nm. In addition, we found smaller particles of approximately 13.1 nm in diameter. We obtained full genome sequences of all four segments of two of the isolated ALSV strains, and partial sequences of one segment from the third strain. Phylogenetic analysis on genome segment 2 of the JMTV group clustered our novel strains with other ALSV strains. We found evidence for the existence of a novel upstream ORF in the glycoprotein-coding segment of ALSV and other members of the JMTV group. Significance StatementWe isolated three strains of Alongshan virus (ALSV) from adult Ixodes persulcatus ticks from two geographically separate areas of Russia in the Ixodes ricinus tick cell line IRE/CTVM19. One of the strains persisted in the IRE/CTVM19 cells without cytopathic effect for three years. Our study confirmed the value of tick cell lines in virus isolation and maintenance of persistent infection. The majority of virions of the ALSV strain Miass527 were enveloped spherical particles with a diameter of 40.5{+/-}3.7 nm. We found evidence for the existence of a novel upstream ORF in the glycoprotein-coding segment of ALSV and other members of the Jingmen tick virus group.

molecular biology↗