Introduction. The human leukocyte antigens (HLA) plays a huge role in the regulation of the immune response, the recognition and destruction of extracellular and intracellular pathogens and maintaining homeostasis. The study of the relationships between the polymorphism of HLA genes and the indicators of humoral and cellular immunity factors in people living in areas endemic for plague against the background of specific prevention in order to clarify and deepen the understanding of the fundamental mechanisms of the patho- and immunogenesis of this disease is an urgent area for research. The aim of the study is to investigate the relationship between HLA class II genes and the indicators of humoral and cellular components of vaccine-induced immunity in people vaccinated with a live plague vaccine and living in the natural foci of plague of Siberia. Materials and methods. The study involved 902 volunteers who live in the natural foci of plague in Siberia. The research complex included quantitative determination of the main classes of immunoglobulins in the blood serum; titer of specific antibodies to the Y. pestis capsule antigen; subpopulation content of blood cells with calculation of the immunoregulatory index; typing of HLA class II genes. The study used ELISA, flow cytometry, real-time PCR and statistical analysis. Results. It has been established that the HLA class II allelic groups DRB1*09, *10, *12, *13, *14, and *15 as well as *04:01 (DQA1) and *03:05 (DQB1) can be significant genetic factors involved in the mechanisms of regulation of cellular and humoral immune system responses during the development of post-vaccination anti-plague immunity. DRB1*16 and DQB1*03:05 stand out in particular, causing deviations of important immunological indicators beyond the reference values. Probable associations of DRB1*09, *13, *14, and *15 with increased titers of specific IgG antibodies to the F1-antigen of Y. pestis have been identified indicating a significant influence in the formation of human humoral vaccine-induced anti-plague immunity. Discussion. We have established a statistically significant association between allelic variants of HLA-II genes and variability in levels of immunoglobulins (IgE, IgG, etc.), cytokines (interleukin-4, interferon-γ), and lymphocyte subpopulations in blood, which confirms the key role of HLA polymorphism in individual immunological reactivity. Conclusion. The obtained data indicate the potential of HLA typing for predicting the effectiveness of specific prophylaxis and for determining the characteristics of post-vaccination immunity formation in humans in plague-endemic territories.
The aim of this study was to assess detection rates of Borreliella burgdorferi sensu lato DNA in ticks and organs of wild and synanthropic small mammals of the Northwestern Federal District. Materials and methods. Samples of ixodid ticks (n = 4818) and small mammals (n = 960) were examined by real-time PCR for the presence of genetic material of B. burgdorferi s. l. Tick collection and small mammal capture were carried out in six subjects of the Northwestern Federal District (St. Petersburg, the Republic of Karelia, the Arkhangelsk, Leningrad, Pskov, and Kaliningrad Regions) in 2020–2025 in accordance with the current guidelines. A commercial reagent kit "AmpliSens TBEV, B. burgdorferi s. l., A. phagocytophilum, E. chaffeensis/ E. muris — FL " was used for detection. Results. The total infection rate of B. burgdorferi s. l. in ticks was 24.06% (1159/4818). The highest infection rate was observed in Ixodes persulcatus — 25.82%, in I. ricinus — 23.20%, in Dermacentor reticulatus — 13.16%. The highest infection rate in ticks was recorded in the Republic of Karelia (40.51%), and the lowest in the Arkhangelsk Region (9.03%). Among small mammals, the overall infection rate was 11.76% (112/960). The most significant reservoir hosts were the bank vole (Myodes glareolus) with 14.76% infection rate, and the yellow — yellow-necked mouse (Apodemus flavicollis) with 14.50% infection rate. The highest proportion of infected mammals was detected in the Republic of Karelia (30.95%) and the Leningrad Region (24.83%). Conclusion. The study results confirm the presence of active natural foci of ixodid tick-borne Lyme disease in all surveyed subjects of the Northwestern Federal District. A significant spatial variability of infection rates of both vectors and reservoir hosts has been established. The obtained data support the need of regular entomological and zoological monitoring to assess risks and optimize preventive measures.
Objective. To identify features of the gut microbiome using 16S rRNA gene sequencing in inbred KK.Cg-a/a (KK) mice and the KK.Cg-Ay/a (Ay) subline with metabolic syndrome (MetS) caused by different genetic disorders, compared to the C57BL/6J (B6) mouse line lacking manifestations of the pathology. Materials and methods. 3–4 months old male mice of three mouse lines were used: 1) KK mice with polygenic genomic disorders contributing to hyperglycemia, insulin resistance, and hyperinsulinemia; 2) the Ay substrain carrying an additional mutant dominant allele of the Agouti yellow coat color gene, exhibiting more severe MetS manifestations; 3) the B6 mouse line, not prone to obesity and diabetes (control group). All mice were of the same age (2 months) and sex (males) and received a normocaloric diet. Morphometry was performed for each animal, and biochemical parameters of blood serum were analyzed. PCR analysis of mRNA expression of neuropeptides and receptors in the hypothalamus was conducted. Mouse fecal samples were examined using 16S rRNA metagenomic analysis. Results. As previously shown, in male mice with genome-wide disorders on a normocaloric diet, obesity and alterations in carbohydrate and lipid metabolism developed, being more pronounced in the Ay group. Animals of the Ay substrain differed from other mice by greater body and liver weight, higher plasma glucose and leptin concentrations, and increased expression of Neuropeptide Y (NPY), Pro-opiomelanocortin (POMC), and Tas1r3. In all animals with MetS, the microbiome differed from the control group by a lower abundance of the family Muribaculaceae and the genus Akkermansia, and an increased percentage of the phylum Bacteroidota (genera Alistipes, Odoribacter, and Bacteroides). A distinctive feature of the Ay microbiome was an increased percentage of the families Enterobacteriaceae and Oscillospiraceae (Ruminococcaceae). Conclusion. Specific features of the gut microbiome characteristic of inbred animals with varying severities of energy metabolism disorders were identified. The models used can be employed to study the pathogenesis of MetS considering the role of microbiota, as well as to develop methods for predicting disease severity and correcting dysbiotic disturbances arising from energy metabolism disorders.
Introduction. The evolutionary changes in the genome of the original SARS-CoV-2 virus clones associated with various combinations of mutations may be determined by geographical features. Monitoring of the molecular genetics and biological properties of regional strains is important for early detection of threats, forecasting the epidemic situation, assessing the risks of drug resistance and developing strategies to combat the virus. The formation of a collection of regional prototype strains reflecting the key characteristics of the Wuhan, Delta, and Omicron gene variants that circulated in Primorsky Krai during the pandemic will provide the basis for a subsequent comparative analysis of the genetic polymorphism and biological characteristics of the evolving variants of the virus. Furthermore, prototype strains can be used as test objects in evaluating the antiviral activity of known and newly developed compounds. The aim of the study: formation of a collection of characterized prototype regional SARS-CoV-2 strains representing the genetic lineages of the main genetic variants: Wuhan, Delta, Omicron isolated in Primorsky Krai during the COVID-19 pandemic. Materials and methods. SARS-CoV-2 strains were cultured in Vero E6 cells. The quantitative determination of the virus was carried out by titration in Vero E6 cells and by RT-qPCR. The genomic sequences of the virus were determined by nanopore sequencing. To assess the adequacy of the strains, remdesivir, an inhibitor of the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp), was used as reference drug in determining sensitivity to therapeutic agents. Results. A panel of prototype SARS-CoV-2 strains representing the dominant sublineages of the Wuhan, Delta, and Omicron genetic variants circulating in the Primorsky Krai during the pandemic (2020–2023) has been formed. Their molecular, genetic, and biological properties have been characterized. Multiple mutations have been identified in the ORF1ab, ORF3a, ORF6, ORF7, ORF8, S, M, E, and N genes characteristic of the corresponding genetic lineages in combinations forming the regional portrait of the virus. A regular decrease in the replicative activity of the virus in Vero E6 cell culture from Wuhan-like genetic variants to Omicron SARS-CoV-2 genetic variants has been established. The adequacy of using regional strains of SARS-CoV-2 as test objects for evaluating the effectiveness of the reference drug, the SARS-CoV-2 RNA-dependent RNA polymerase inhibitor has been proven. Conclusion. Prototype strains of SARS-CoV-2 for genetic lineages isolated during the COVID-19 pandemic, having different virulence and containing a large set of mutations, can be used in virological, molecular biological and pharmaceutical methods for comparative study of the genetic relationship and biological properties of SARS-CoV-2 genetic variants, as well as for the development of treatments and COVID-19 prevention.
The aim of this study was to examine spatio-temporal changes in the incidence of tick-borne encephalitis (TBE) in the Kirov Region over a thirty-year period. Materials and methods. The data used were data on the incidence of TBE in the Kirov Region. Statistical hypotheses were tested at a significance level of 0.05. Statistical processing of the data was performed using the MS Excel19 and STATISTICA 10.0 software packages. Results. An analysis of the temporal dynamics of TBE incidence in the Kirov Region (1994-2023) revealed the absence of a clear trend. Significant differences in the intensive TBE incidence rates (number of cases per 100,000 people) were found between the vegetation zones of the region in each of the aggregated time periods. In the middle taiga zone, statistically insignificant fluctuations in high incidence rates were recorded. In the southern taiga zone, a significant upward trend was observed, indicating a worsening epidemiological situation. In the coniferous-broadleaf forest zone, a significant downward trend was observed, with a significant decrease in incidence rates and interregional variability over the past decade. Discussion. An inverse correlation was identified between the baseline incidence rate and its change during 1994–2003, indicating "regression to the mean"—a phenomenon that was absent in the subsequent 10-year period. This indicates a stabilization of the epidemiological situation and the emergence of new patterns of TBE distribution in the Kirov Region at this stage. This process may be influenced by numerous biotic and abiotic factors, the role of which requires further study. Conclusion. The data obtained confirm the need for further study of this problem with the aim of optimizing existing prevention programs.
Background. The most urgent problem of medicine is the fight against viral diseases. Preventive measures in the form of antiseptics with virucidal effect (VE) play an important role. Antimicrobial properties have been noted in compounds based on rare-earth metals. The aim of the study was to investigate the VE of lanthanum nitrate hexahydrate (LNH) and compositions based on it in order to establish the possibility of using them in the composition of topical antiseptics. Materials and methods. The VE of compounds was studied on the model of viruses: poliovirus, adenovirus, human immunodeficiency virus (HIV-1), herpes simplex virus (HSV-1). The VE was assessed by degree of reduction of virus titer in lg TCID50. The following compounds were studied: organic lanthanum composition (OLC), consisting of LNH (La(NO3)3·6H2O), triethylene glycol (TEG), ethyl carbitol (EC), glycerol, H2O and NaOH, as well as solutions of LNH in H2O and glycols: TEG, EC, 1,2-propylene glycol (PG), 1,3-butylene glycol (BG), polyethylene glycol-400 (PEG) and glycols themselves. Results. OLC reduced titers of poliovirus and adenovirus by 4.0-4.5 lg TCID50 in vitro, on surfaces by 4.0–5.0 lg TCID50 with disinfection time of 1–2 minutes. Components included in OLC reduced the titer of poliovirus by 3.1-4.0 lg TCID50. The reduction of HSV-1 titer of all compounds amounted to 4.0–4.3 lg TCID50. La(NO3)3·6H2O in PG, BG, PEG-400 and EC reduced HIV-1 titer by 4.8–5.3 lg TCID50 at pH below 4.62. The VE of LNH on HIV-1 on the surface is the reduction of the titer by 2.3–3.3 lg TCID50, depending on disinfection duration, the HSV-1 reduction titer amounted to 3.8 lg TCID50. Conclusion. For the first time it has been established that LNH and OLC possess a virucidal effect against both enveloped and non-enveloped viruses and can be considered as components of virucidal antiseptics. The VE of LNH without participation of additional compounds is very promising.
Introduction. Continuous monitoring of the epidemiological situation is one of the key elements of a country's biological safety. The development and increasing accessibility of high-throughput sequencing technologies have led to the incorporation of genomic data into public health decision-making systems, known as genomic epidemiological surveillance. Effective implementation of genomic epidemiological surveillance for circulating pathogens requires finding a balance between data generation speed, estimation accuracy, and rational use of resources. Consequently, there is a need to develop evidence-based strategies for biological sample selection. Aim: To justify the choice of methods for calculating the minimum sufficient sample size for sequencing depending on the objectives of epidemiological surveillance. Materials and methods. This study presents a comparative analysis of two approaches to genomic monitoring: routine surveillance and targeted sentinel surveillance. The choice of statistical approaches for calculating the minimum sufficient sample size for each objective is justified, with specific examples that allow determining the required sequencing volume taking into account the current epidemiological situation and the prevalence of pathogen variants in the population. Results. The study presents sample size calculation results depending on the objective: establishing the proportion of existing variants for routine surveillance, or detecting rare variants within sentinel surveillance at a predetermined prevalence threshold for a rare/new variant with a specified probability. For routine surveillance, the sample size was calculated based on the requirement for estimation precision of proportions (margin of error 5%) at a confidence level of 95%. For sentinel surveillance, the sample size was calculated under the condition that the probability of missing a variant (not detecting a single case) does not exceed 5%. The statistical results are presented in the form of graphs and calculation tables. Conclusion. The proposed methods for calculating sample sizes for genomic monitoring depending on the objective can serve as a practical tool for epidemiological surveillance, increasing its efficiency. The use of these calculation methods will make it possible to obtain mathematically sound results regarding the genotypes of circulating pathogens and their degree of representation in the population.
Introduction. The use of bacteriophage derivatives, whose growth indicator is a fluorescent signal (fluorophages), seems to be very promising in microbiological analyses. The first mandatory stage of their design (in particular, of fluoromycobacteriophages) is the optimization of the structure of the fluorescent protein operon (FPO) with control of its ability to provide fluorescence of mycobacteria The aim of the study is to construct different variants of FPO in plasmids and compare their expression in mycobacteria by the magnitude of the fluorescent signal. Materials and methods. As part of the pMind plasmid, which is capable of replicating in both Escherichia coli and mycobacteria, FPOs of different structures with the hsp60 promoter producing the TurboGFP protein have been constructed using conventional genetic engineering methods. Plasmids with FPOs were introduced into Mycobacterium smegmatis cells by elecroporanion. Results. The greatest fluorescent signal was provided by FPO, in which the hsp60 ribosome binding site in the 5’-untranslated mRNA region was replaced by that for the gp9 gene of the TM4 phage. The necessity of the presence of a transcription terminator in FPO is shown, as well as the importance of preserving the mRNA structure before the point of translation initiation. Conclusion. The optimal structure of FPO has been selected for its subsequent incorporation into the phage genome. Elements of the operon structure important for the expression of a foreign protein in mycobacteria have been identified.
Introduction. HIV-1 drug resistance (DR) is a significant and ongoing public health problem at the present time. As access to antiretroviral therapy increases, the risk of developing transmitted DR also increases. DR testing within the first year after infection improve the accuracy of detecting drug-resistant HIV-1 variants. The aim of this study was to analyze HIV-1 genetic variants and transmitted DR among individuals with recent infection identified in the Krasnodar Region. Materials and Methods. A sample of 295 patients was recruited; recent infection was confirmed with epidemiological information, laboratory evidence of seroconversion, and/or testing results using a specialized kit for estimating the approximate timing of HIV-1 infection. Nucleotide sequences of the HIV-1 genome fragment (positions 2253-3368) were obtained using population Sanger sequencing, the virus genetic variant was determined, and DR analysis was performed. Results. Sub-subtype A6 was dominant in the study sample (78.64%), with an increase in its proportion over time: 71,05% in 2014-2018 vs 83,43% in 2019-2022 (p = 0,0116). Surveillance DR mutations (SDRM) were detected in 29 patients (9,83%), with an upward trend: from 5,26% in 2014-2018 to 12,71% in 2019-2022 (p = 0,0365). Drug-resistant HIV-1 variants were detected in 49 patients (16,61%). DR to NNRTI was the most frequently recorded (13,22%), while DR to PI (2,03%) and NRTI (1,02%) was less common. Conclusion. The results indicate a significant level of detection of HIV-1 transmitted DR among individuals with recent infection, which requires the adoption of appropriate measures within the framework of surveillance of drug-resistant HIV-1 variants.
The emergence of the norovirus GII.4 Sydney variant in 2012 caused a significant worldwide increase in gastroenteritis outbreaks. The article focuses on the problem of the emergence and further spread of the norovirus GII.4 Sydney variant, which is still one of the leading causes of viral gastroenteritis, especially in young children. The review summarizes data from the modern scientific literature on the detection of norovirus GII.4 Sydney and its recombinant forms — GII.4 Sydney[P31], GII.4 Sydney[P4 New Orleans], GII.4 Sydney[P16] и GII.4 Sydney[P12] in various countries. This review presents a comparison of the amino acid composition of the antigenic epitopes in the main capsid protein (VP1). The analysis focuses on four recombinants of the Sydney variant and includes a comparison with other variants (Grimsby 1995, Farmington Hills 2002, Hunter 2004, Yerseke 2006a, Den Haag 2006b, New Orleans 2009).
The aim of this study was to conduct an epidemiological analysis of hepatitis C infection in children with oncohematological diseases (OHD) using phylogenetic analysis of HCV nucleotide sequences and to analyze the causes and factors of HCV nosocomial transmission. Materials and methods. A retrospective analysis of HCV genetic isolates obtained from children with oncohematological diseases treated at the «Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology» (the Center) was conducted. The analysis included all children with HCV markers (anti-HCV and/or HCV RNA) identified between 2013 and 2025 during hospitalization and treatment at the Center—a total of 146 children. The children's ages ranged from 0 to 18 years, and from September 1, 2022, to 21 years. Samples were taken from the Center's bacteriology laboratory collection. Genotyping and phylogenetic analysis were performed at the Central Research Institute of Epidemiology of Rospotrebnadzor for 30 patient blood samples containing HCV RNA in quantities sufficient for analysis (at least 1000 IU/mL). To compare the distribution of HCV genotypes, the VGARus database data from 997 individuals was used. The core/E1 region of the HCV genome was sequenced and a phylogenetic analysis was performed. A Bayesian approach was used with the BEAST2 software package. The tree was visualized using FigTree. Results. In the structure of HCV genotypes isolated from children in the oncohematology departments, genotype 3a was predominant (77%), while 1b accounted for 23%. In contrast to the general population, where genotypes 3a and 1b circulate with equal frequency, the prevalence of genotype 3a among children with OHD indicates a greater involvement of this genotype in cases of nosocomial infection. Phylogenetic analysis revealed three common HCV clusters: 14 children with genotype 3a (13 children from the Amur Region and 1 child from the Altai Krai) and two common clusters with genotype 1b (2 patients each from the Kyrgyz Republic and Uzbekistan). The majority of HCV infection cases in children with OHD (60%) were nosocomial in origin. Cases of HCV infection in children from the Amur Region are associated with a long-standing chronic HCV epidemic in the oncohematology department of the Amur Regional Children's Clinical Hospital. No cases of infection have been identified at the Center. A patient from the Altai Krai region may have been infected at the Center in 2013-2014 during blood collection from a central venous catheter (CVC) due to improper hand sanitization, glove changing, aseptic technique, or work surface zoning. Standardization of procedures, implementation of aseptic non-touch technique (ANTT), training, and monitoring of staff knowledge and skills, widely implemented in the Center's work, have demonstrated high effectiveness, resulting in the absence of HCV transmission cases for over 10 years. Conclusion. Nosocomial HCV transmission in the OHD departments requires the widespread implementation of modern approaches to preventive and anti-epidemic measures, such as aseptic non-touch technique (ANTT), standardization of procedures, staff training, and knowledge and skills audits.
Introduction. The goal of the WHO Global Polio Eradication Initiative has not yet been solved, and the surveillance of diseases with acute flaccid paralysis (AFP) remains its key element. It is still relevant for ensuring the sanitary and epidemiological well-being of Russia. Aim: analysis of indicators and results of polio/AFP surveillance in 2013-2024 for purposes of surveillance quality assessment and improvement. Materials and methods. Information on surveillance indicators and results of virological investigation was obtained in national reporting documents. Results. Over 12 years, 5,016 cases of AFP have been registered. Surveillance quality indicators were generally in line with WHO recommendations, but the COVID-19 pandemic had a negative impact on the detection of AFP cases at the clinical level. The majority of patients were children under 5 years of age (50.54%), boys (58.8%), the majority (82.46%) were vaccinated against polio. Polioviruses (PV) were isolated from 1.85% of cases, PV3 (48.4%) prevailed, non-polio enteroviruses — from 1.46% cases, CVB1–6 (34.9%) and EV-A71 (17.5%) were predominant. The majority of AFP cases (30.78%) were polyradiculoneuropathies, 34 cases (0.68%) were poliomyelitis. The occurrence of 30 cases of vaccine-associated paralytic poliomyelitis was associated with violations of sanitary and epidemiological requirements for its prevention. Four cases were associated with PV of vaccine origin (VDPV) types 1 and 3. The "age" of VDPVs corresponded to 1-2 years of circulation, there was no genetic evidence of human-to-human transmission. Conclusion. High level of polio/AFP surveillance in Russia allowed to identify epidemiologically significant PVs and timely carry out anti-epidemic measures. The continuing threat of the international spread of poliomyelitis is the basis for future improving surveillance. The surveillance platform provides information about other (non-polio) pathogens that cause diseases with AFP syndrome.
Introduction. Immunohistochemical (IHC) analysis is one of the main methods for detecting and visualizing the protein determinants of the virus in organs. The nanoscale structures of viruses complicate the visualization of particle topography, which prevents a more detailed understanding of the pathogenesis of viral infections. Unfortunately, general IHC protocols are not universal and often their application in special cases is impossible. Optimizing the coloring methodology can significantly save research time. Based on this, this paper describes a step-by-step methodology for IHC staining of paraffin sections of animal organs infected with the SARS-CoV-2 virus. The purpose of the study. Optimization of the chromogenic IHC staining protocol when working with infected material, using the example of SARS-CoV-2. Materials and methods. IHC analysis was performed on paraffin sections of lung tissue of ferrets (Mustela putorius furo) infected with Omicron and Delta strains of SARS-CoV-2. Results. During the study, it was demonstrated that the optimal exposure time for samples with hydrogen peroxide was at least 30 minutes. The use of BSA before the application of primary antibodies also contributed to a decrease in background staining, while the optimal concentration of the reagent was at least 1%. It is noteworthy that the addition of BSA to the primary antibody solution also contributed to a decrease in the non-specific signal. In the context of the current work, dilution of antibodies applied to S-protein by 1000 times was optimal to minimize the proportion of non-specific tissue staining. Conclusion. In the work on optimizing the IHC protocol for paraffin sections, the main aspects affecting the staining quality were demonstrated and described. When working with material containing SARS-CoV-2, options for eliminating methodological mistakes were proposed.
Introduction. Influenza A virus is one of the major global infectious threats. Along with seasonal epidemics, zoonotic influenza viruses (subtypes А(H5Nх), А(H7Nх), А(H9N2)) pose an increased risk, requiring constant monitoring of herd immunity. The aim of the work was to study human blood sera against influenza viruses, both vaccine strains and virus strains with pandemic potential. Materials and methods. Blood sera from healthy donors collected in different regions of the Russian Federation were tested in the hemagglutination inhibition (HI) assay with vaccine strains of influenza A and B viruses. Blood sera from individuals involved in poultry farming were tested in the hemagglutination inhibition and virus neutralization assays with avian influenza viruses. Results. From 2021 to 2025, only a few samples were positivein the HI assay with A(H5Nx) influenza viruses, and approximately 1% of samples were positive in HI assay with A(H9N2) virus. All samples positive in the HI assay with A(H5) viruses were negative in the neutralization assay, and approximately 85% of samples positive in the HI assay with A(H9N2) virus contained virus-neutralizing antibodies. Conclusion. By 2023–2024, humoral immunity to seasonal influenza, following its decline during the COVID-19 pandemic, was at levels typical of pre-pandemic seasons and generally met the recommendations of Rospotrebnadzor and the World Health Organization. Currently, influenza viruses with pandemic potential, such as subtypes A(H5N1) and A(H9N2), are not circulating in the human population in the Russian Federation. However, insufficient herd immunity to seasonal influenza viruses poses additional risks for the emergence and spread of new virus variants.
Introduction. Cases of hemorrhagic fever with renal syndrome (HFRS) have increased over the past ten years, including in regions previously non-endemic for HFRS. Approximately 98% of all cases in Russia are associated with Puumala hantavirus, while only about 2% of sporadic cases are caused by Hantaan, Amur, Seoul, Kurkino and Sochi hantaviruses. The main HFRS foci are located in the European part of Russia. In endemic areas, the risk of infection exists for all population groups, especially military personnel and workers in the forestry and agricultural sectors. The etiotropic therapy absence can be solved only through vaccination. However, licensed vaccines based on Hantaan or Seoul hantaviruses do not provide protection against Puumala hantavirus, for which no vaccines currently exist worldwide. An experimental vaccine (EV) for the prevention of HFRS, based on Puumala and Hantaan hantaviruses, has been developed at the Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of the Russian Academy of Sciences (Institute of Poliomyelitis). The aim of the study is to determine the EV immunogenicity against HFRS in a guinea pig model using various immunisation schedules. Materials and methods. The induction of neutralising antibodies (NAb) was assessed in the blood serum of guinea pigs following immunisation with mono- and bivalent EV by means of a neutralisation assay based on 50% suppression of focus-forming units in Vero E6 cell culture. The results indicate the formation of a humoral immune response following EV immunisations. Immunogen administration induced the NAb production up to peak values followed by a decrease after certain intervals. Repeated EV administration showed similar NAb dynamics with prolonged circulation. Three variants involving double immunisation and a subsequent booster after one year were prioritised for clinical trials (0, 150, 300; 0, 14, 182, 364; 0, 30, 364). Conclusion. This study indicates the development of a persistent and intense immune response, the strength of which depended on the EV immunisation schedule. The optimal timing for immunogen administration has been determined. The results of this study will be the basis for subsequent clinical trials of hantavirus vaccines.
Introduction. Hepatitis C virus (HCV) remains a significant public health concern. The application of existing antiviral agents is restricted by their high cost and the development of viral resistance, while vaccine development is impeded by the considerable genetic variability of HCV. The outcome of infection is largely determined by the host's genetic factors, which influence both the viral entry into the cell and the effectiveness of antiviral immunity. Identification of genetic determinants involved in these processes is essential for understanding pathogenesis and discovering novel therapeutic targets. Objective. A comprehensive assessment of the potential involvement of candidate genes and their products in the pathogenesis of HCV infection at the stages of viral entry into the cell and the formation of the host immune response, based on an integrative analysis of gene expression, subcellular localization of their products, and participation in molecular pathways and biological processes. Materials and methods. In this study, a comparative analysis of 35 most promising candidate genes was performed against five background genes (CD81, CLDN1, LDLR, OCLN, SCARB1) encoding key HCV entry receptors. To analyze biological mechanisms associated with priority genes, the FUMA GWAS platform was used in the functional mapping mode GENE2FUNC (https://fuma.ctglab.nl/gene2func). Evaluation of candidate genes included analysis of their expression profiles, subcellular localization of protein products, as well as involvement in molecular pathways and biological processes. A ranking scoring system was developed, based on point-based ranking, which allowed determining the significance of each candidate gene in the context of its potential involvement in HCV pathogenesis. The system includes sequential assessment by several independent criteria, the results of which are summed into a single score. The degree of association between candidate genes and background genes was assessed using the phi-correlation coefficient (φ) across categories of subcellular localization, molecular pathways, and biological processes. Results. Application of the developed scoring system identified 25 significant candidate genes. The highest scores were obtained for genes involved in intercellular junction organization (CLDN3, CLDN5, CLDN12, ESAM, F11R, TJP1, TJP2) and lipid metabolism regulation (APOE, LDLRAP1). Enrichment of several candidate genes in immunological processes was revealed. A stable association of C3 and CD19 genes with immune process regulation was established, which is of particular interest in light of HCV's ability to infect mononuclear cells. The APOE, ITGB1, F11R genes demonstrated involvement in inflammatory and defense responses, while IFITM1 was associated with response to cytokine stimulation. Conclusion. A group of candidate genes potentially influencing HCV infection pathogenesis both at the viral entry stage and through immune modulation was identified. The obtained data expand understanding of virus-host interactions and justify the need for experimental validation of the identified genes as potential biomarkers and therapeutic targets.
Introduction. Vibrio cholerae motility plays a key role in the pathogenesis of cholera, so finding ways to suppress it is a promising approach to combating this infection. Objective: to study the effect of Fluorothiazinone on the motility of V. cholerae. Materials and methods. Flagellar motility was determined in 0.3% agar, with the motility zone measured, in 40 strains V. cholerae El Tor of varying epidemiological significance. The ability of these strains to acquire resistance to Fluorothiazinone was also assessed through repeated subcultures on alkaline agar containing Fluorothiazinone (100 mg/L). Results. A significant decrease in the motility of all studied cultures was observed in the presence of Fluorothiazinone, without the development of resistance. Conclusion. The dose-dependent ability of Fluorothiazinone to reduce the motility of V. cholerae was demonstrated for the first time.
Background. Rotavirus infection remains the leading cause of severe gastroenteritis in children under 5 years of age, particularly in low-income countries. Existing live oral vaccines have reduced efficacy in regions with high infection rates, and there is no etiological treatment available. Consequently, new platforms are being actively investigated: mRNA vaccines (capable of overcoming maternal antibody interference) and RNA interference (allowing for direct suppression of viral replication). The aim of this review is to systematize data on the molecular mechanisms of rotavirus replication and pathogenesis, epidemiology, and diagnosis, as well as to provide a comparative analysis of current vaccines and promising RNA technologies (mRNA vaccines, RNA interference) for the prevention and treatment of rotavirus infection. Objectives: to describe the structure and replication of the virus, the epidemiological situation, and diagnostic methods; to evaluate existing vaccines; and to analyze two areas of RNA technology: mRNA vaccines, as prevention, and RNA interference, as therapy based on siRNA, miRNA, and lncRNA. Conclusions. Conventional vaccines remain the foundation of mass vaccination programs, despite their limitations. mRNA vaccines (especially trivalent ones based on VP8*) induce durable humoral and cellular immunity in preclinical studies, overcoming maternal antibody interference. RNA interference (siRNA, miRNA) allows for direct suppression of viral replication. However, at present, no mRNA candidate vaccine has advanced to the clinical trial phase. Further research is needed to improve vaccine delivery systems and increase its thermal stability.
Introduction. The severe consequences of the COVID-19 pandemic highlight the lack of preparedness of national health systems to counter such biological threats. In this regard, the development of preventive means for specific prophylaxis of COVID-19 and other coronavirus diseases remains urgent. The aim of the study was to obtain an attenuated Оmicron-like SARS-CoV-2 strain to create a preventive live attenuated COVID-19 vaccine. Materials and methods. For SARS-CoV-2 infection modeling in vitro and virus propagation, Vero CCL-81 cell culture as well as laboratory strains SARS-CoV-2 Dubrovka (Wuhan-like) and FEB2 (Omicron BA.5.2) were used. Attenuation of the FEB2 strain was carried out by cultivation for 24 passages in Vero CCL-81 cells at a temperature gradually lowered to 24°C, followed by triple cloning. COVID-19 modeling in vivo was performed on golden Syrian hamsters. Viral load was assessed by virus titration by the CPE endpoint and SARS-CoV-2 RNA quantitation in real-time RT-PCR. The primary structure of the SARS-CoV-2 genome was determined by nanopore sequencing. Antibodies to SARS-CoV-2 in hamster sera were detected by ELISA. Results. A non-pathogenic for Syrian hamsters temperature-sensitive (ts) mutant of the omicron-like SARS-CoV-2 F-F3 strain, which possesses attenuation markers such as ts phenotype and reduced immunogenicity, was obtained. The mutant F-F3 strain did not affect the lungs in infected Syrian hamsters, unlike the parental strain, but retained viability in the nasal passages and immunogenicity. A single intranasal immunization of hamsters with the F-F3 ts strain caused seroconversion in them with the production of neutralizing antibodies. An important characteristic of F-F3 strain is low transmissibility and the stability of attenuation phenotype when cultured at 33°C. Conclusions. The combination of the identified characteristics of the attenuated SARS-CoV-2 F-F3 strain indicates the rationality of further investigation of its safety and efficacy in an animal model of COVID-19.
