Vol 14, No 3 (2024)

Among respiratory viruses, the most serious complications are caused by influenza A and B viruses, as well as coronaviruses. Most studies determined the absolute content of interferons (IFNs) of different types in blood serum. However, serum IFN protein concentrations do not always reflect the level of antiviral protection. The purpose of this study was a comparative assessment of interferon status in patients with ARVI: influenza and the acute stage of COVID-19. Materials and methods. We used biomaterial in the form of whole blood samples from 113 patients with influenza and 110 patients in the acute phase of moderate COVID-19. The body’s antiviral defense during ARVI was assessed by determining the activity of type I and II interferons produced by blood leukocytes using the “Interferon status” method in a cell-virus system simulated in vitro. Results. This work reveals a statistically significant decrease in the biological activity of interferons produced by blood leukocytes in influenza and a deficiency of IFN activity in COVID-19, compared with reference values, and also shows possible prospects for the treatment of these nosologies with such immunoactive drugs as IFN inducers (cycloferon, Kagocel) and immunomodulators (ingavirin, multicomponent vaccine Immunovac-VP-4). Conclusion. The results of IFN activity are necessary to assess the antiviral potential of the body, especially with COVID-19, given the “novelty” of the infection, the severity and variety of its clinical manifestations. Today it is known that the SARS-CoV-2 virus is capable of penetrating not only into the epithelial cells of the upper respiratory tract, epithelial cells of the stomach and intestines, but also into the cells of the esophagus, heart, adrenal glands, bladder, brain, as well as into the vascular endothelium and macrophages. Coronavirus SARS-CoV-2 inhibits the expression of cellular genes, including innate immune genes, and has a negative effect on the IFN system. The use of IFN inducers and immunomodulators for influenza and COVID-19 has shown immunological feasibility and clinical promise.

Morality rates in COVID-19 are dependent on timely diagnosis. Therefore, studying the relationship between laboratory markers and the severity of disease is important. The first wave of COVID-19 associated with the spread of the original strain of SARS-CoV-2, showed higher mortality rates caused by cytokine storm. As the viral variant changed, a change in the disease course towards a less pronounced inflammatory reaction was observed. These changes affected major players of inflammation, cytokines. However, cytokines are not the only markers in the inflammatory response. The purpose of this work was to determine the significance of laboratory markers in inflammation: WBC, C-reactive protein, ferritin, fibrinogen, and D-dimer. The study included 227 patients with acute COVID-19 in the first 5–7 days from the onset of the disease from January 2021 to March 2022. When compared with reference, all groups were characterized by reduced absolute values of lymphocytes. Correlation analysis between the absolute value of lymphocytes and plasma cytokine concentrations also revealed statistically significant strong relationships with the level of the chemokine CCL22/MDC. Given that CCL22/MDC is an important component of lymphopoiesis, its low concentrations may indicate dysregulation of this process in COVID-19. In addition, we noted a positive correlation between the level of C-reactive protein and IL-6 in peripheral blood. IL-6 is a proinflammatory cytokine, and its elevated levels have been associated with the development of severe COVID-19. One of its functions is the induction of C-reactive protein, and this trend persists regardless of which variant causes COVID-19. We also noted positive correlations between the concentrations of fibrinogen and IL-18, ferritin and IL-6, IL-18. Both of these proteins are involved in inflammation along with cytokines. The literature provides data on the significance of these markers for determining the severity of COVID-19. There is evidence of a synergistic effect of ferritin and IL-18 against viral pathogens. Of interest was the negative correlation between plasma D-dimer levels and IFNα. At the same time, data on the role of the latter in thrombus formation processes are increasingly appearing in the literature.

Heart transplant patients are at an increased risk of COVID-19 infection adverse outcomes because of underlying immunosuppression and concomitant comorbidities. To date, all large-scale randomized controlled trials for various COVID-19 vaccines have excluded solid organ transplant recipients. Therefore, the efficacy and safety of coronavirus infection prevention using COVID-19 vaccines in transplant heart patients has not been sufficiently studied. In this research, the evaluation of virus-specific immunological reactions after vaccination (double Vero Cell vaccination and Sputnik Light booster vaccination) in heart transplant patients has been carried out. In vaccinated heart transplant individuals who did not have a history of COVID-19, starting from 4–6 months after the 2nd dose of the vaccine, an increase in antibodies to S protein level of was observed, while maintaining statistically significant differences for 9–12 months after vaccination (regardless of whether with or without booster vaccination). However, the concentration of antibodies remained low, and 37% of patients detected no antibodies. In vaccinated heart transplant individuals following the previous COVID-19 infection, as compared to seronegative patients, post-vaccination immunity is accompanied by maintaining a high level of virus-specific IgG antibodies to the S protein of the SARS-CoV-2 virus in the dynamics of the post-vaccination period with a statistically significant increase of these antibodies by 9–12 months after booster vaccination. The specific cellular response (according to the assessment of CD3⁺154⁺ and CD3⁺IFNγ⁺ TNFα⁺ cells) to the S protein of the SARS-CoV-2 virus remained low throughout the entire follow-up period, was recorded in 5–40% of heart transplant patients and statistically significant changes in the number of spikereactive lymphocytes were observed in patients with a history of COVID-19 by 4–6 months after administration of the 2nd dose of the vaccine. This, together with the results of the assessment of the humoral response, indicates a more pronounced post-vaccination immunity in patients with a hybrid immunity. While developing a methodology for assessing the risk and benefit of a vaccination strategy for individual heart transplant patients, clinical efficacy, ongoing monitoring of rare serious adverse events, and data on vaccine immunogenicity should be taken into account.

In 2019, the COVID-19 pandemic began and changed the world. Coronavirus SARS-CoV-2 has caused widespread illness and death around the world. In this regard, vaccination become the most important tool for creating herd immunity. Our study analyzed the dynamics of pro- and anti-inflammatory cytokines and antibodies to SARS-CoV-2 in the blood serum of young patients before and after vaccination against COVID-19. The study group included 76 young men. Determination of IL-1β, IL-4, IL-6, IL-8, IL-10, IL-17, IFNγ, TNFα and IgM and IgG antibodies to COVID-19 in venous blood sera was carried out twice, by ELISA using the test systems of Vector-Best Company, Novosibirsk. The first blood samples were carried out before vaccination, the second — 1 month after vaccination against COVID-19. The results were processed using STATISTICA 8.0. The vaccinated people were monitored for 6 months after vaccination. Levels of indices before vaccination: IL-1β (5.6 pg/ml (Q₂₅–Q₇₅ = 3.1–14.2); IL-4 (1.02 pg/ml (Q₂₅–Q₇₅ = 0.75–1.28); IL-6 (27.8 pg/ml (Q₂₅–Q₇₅ = 7.1–59.9); IL-8 (29.9 pg/ml (Q₂₅–Q₇₅ = 19.51–32.14); IL-10 (4.47 pg/ ml (Q₂₅–Q₇₅ = 1.84–14.75); IL-17 (7.33 pg/ml (Q₂₅–Q₇₅ = 6.82–8.58); IFNγ (0.7 pg/ml (Q₂₅–Q₇₅ = 0.4–0.9); TNFα (3.9 pg/ml (Q₂₅–Q₇₅ = 2.2–6.4). Levels of indices after vaccination: IL-1β (1.6 pg/ml (Q₂₅–Q₇₅ = 1.4- 2.2); IL-4 (0.84 pg/ml (Q₂₅–Q₇₅ = 0.59–1.12); IL-6 (1.2 pg/ml (Q₂₅–Q₇₅ = 0.6–1.7); IL-8 (10.1 pg/ml (Q₂₅–Q₇₅ = 3.8–28.9); IL-10 (5.84 pg/ml (Q₂₅–Q₇₅ = 1–9.99); IFNγ (0.6 pg /ml (Q₂₅–Q₇₅ = 0.3–0.8); TNFα (0.6 pg/ml (Q₂₅–Q₇₅ = 0.3–1.9). Both before and after vaccination against SARS-CoV-2, different distributions of cytokine levels were identified with a downward trend, but despite this, strong correlations were observed between many of them, which indicates an increase in the tension of the immune system in response to vaccination. When calculating the ratio of pro- and anti-inflammatory cytokines, its two-fold decrease was revealed, which reflects a decrease in the levels of pro-inflammatory cytokines after vaccination. The level of IgG antibodies to COVID-19 exceeded the protective level: more than 14 times in 98% of subjects. Further research into the impact of SARS-CoV-2 vaccination on innate immunity will allow us to reconsider the current vaccination strategy and determine the best approach to preventing COVID-19.

Plasmablasts are a population of short-lived B cells that appear in the circulation shortly after vaccination and during acute infection. Plasmablasts are formed from resting B lymphocytes, from which they differ in their ability to secrete antibodies, making them similar to plasma cells. Plasmablasts are terminally differentiated cells that can form at various nodes and branches of the B cell response. The plasmablast response is an indicator of the success of vaccination and also helps in predicting antibody levels after recovery or vaccination. However, the definition and classification of plasmablasts faces great experimental and theoretical difficulties. The aim of the work was to determine the characteristics of the plasmablast response during acute SARS-CoV-2 infection. The study included patients (n = 28) with a severe form of COVID-19. Blood sampling was carried out once on the 10–18th day from the moment of hospitalization. B cells were isolated by immunomagnetic separation. Cells were phenotyped using flow cytometry. Secretion of IgM and IgG was determined by ELISpot method. B cell subsets were isolated using a cell sorter. Patients with COVID-19 had an approximately fourfold increase in total plasmablast levels compared to healthy donors. An even more pronounced excess over the negative control was observed for RBD-specific plasmablasts. In terms of their composition, plasmablasts were one third IgM⁺ cells. This distribution between B-cell BCR receptor isotypes was consistent with the primary nature of the immune response in COVID-19. Approximately a third of plasmablasts carried the CD138 antigen. CD138 marker is characteristic of the late stage of plasmablast maturation and is also found on plasma cells. The CD27⁺CD38⁺ population was divided according to the expression of the CD138 antigen. Using the ELISpot method, we have shown that a significant portion of circulating plasmablasts are antibody-secreting cells. Among circulating plasmablasts, both early and late plasmablasts can be distinguished, which are characterized by the absence of a surface BCR, but which carry the CD138 antigen. Determining how plasmablasts relate to other B cell populations is of paramount importance for the development of new treatments for COVID-19 and for the creation of promising vaccines against SARS-CoV-2 infection.

Currently, the problem of persistent myocardial damage in patients who have had COVID-19 has become one of the most pressing in the practice of cardiologists. The main mechanisms of the pathogenesis of post-COVID myocarditis are associated with a violation of immunoregulation caused by long-term persistence of the virus in the heart muscle and the launch of autoimmune processes that can lead to myocardial remodeling, the formation of myocardiosclerosis and the development of heart failure or arrhythmia. The purpose of this study was to assess the dynamics of the production of certain cytokines (IFNg, IL-4, IL-17А), which may indirectly reflect the activation of various immune response pathways in patients with post-COVID myocarditis, depending on the duration of the disease and the degree of heart failure. The study included 32 patients with post-COVID myocarditis, 36 patients with myocardial cardiosclerosis, and 10 apparently healthy individuals. It was found that in all patients with post-COVID myocarditis, the content of IFNg, IL-4, IL-17А in the blood serum was higher than in patients with myocardial cardiosclerosis (p < 0.001; p < 0.05; p < 0.01, respectively) and conditionally healthy individuals (p < 0.001; p < 0.01; p < 0.001, respectively). Compared with the group of patients with no or moderate severity of symptoms of heart failure (functional class 0–II), those with more severe heart failure (functional class III) had a higher level of interferon gamma (p < 0.05). When comparing the results obtained with similar indicators in patients with myocardial cardiosclerosis who have the same degree of heart failure, no statistically significant differences were obtained. The maximum content of IFNg in post-COVID myocarditis was observed in the 2nd week of the disease (p < 0.001 compared with the control group); then its level gradually decreased and by the end of the 2nd month there were no longer any significant differences. The opposite trend was observed in relation to the content of IL-4 and IL-17А: in the first two weeks, no statistically significant differences were detected with the control group, but then their content increased quite quickly (p < 0.001 compared with the control group by the end of the first month of the disease) and continued to remain the same high until the end of the 2nd month. Thus, monitoring the content of IFNg, IL-4, IL-17А in blood serum can to some extent provide an idea of the sequence of development of the immune response in post-COVID myocarditis. An increase in IFNg levels in the early stages of the disease is probably associated with an increase in the manifestations of heart failure. Th17-mediated mechanisms may be involved in the process of myocardial remodeling resulting in myocardial cardiosclerosis.

Broncho-obstructive syndrome (BOS) after coronavirus infection is characterized by long-term, dry and painful cough which is hard for treatment, significantly reducing the quality of life of the patients. The goal of the study: to investigate the specific features of clinical manifestations of BOS diagnosed for the first time in patients belonging to different age groups in post-COVID-19 period and to estimate the degree of mitochondrial dysfunction by the imbalance of the enzymes of cellular energy metabolism. Materials and methods. 298 patients with BOS (age 18–78) were observed continuously for 2 years. Standard clinical, biochemical and functional examination was carried out, Saint George`s Respiratory Questionnaire (SGRQ) was used. Mitochondrial dysfunction was determined by the ratio of levels of two enzymes, lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH), in peripheral blood lymphocytes. Statistical data processing was performed in STATISTICA 10.1 program package. Results. The duration and severity of BOS manifestations increased with age, they were the most prominent in the age group older than 60 y/o. Bronchial asthma was diagnosed for the first time in 85 patients, most of them belonging to the group 18–25 y/o. In all the patients with BOS, the SGRQ coeffitient was above 50, and comorbidity was established in 82.4% of the patients. The longest duration of BOS (49.4±3.5 days) was established in the group older than 60 y/o (n = 86). LDH/SDH ratio decreased from 6 to 4.8–5.2 a.u. in all the age groups. Such changes should be taken into account in the patients from young age groups. Conclusion. The revealed low values of LDH/SDH ratio have not been shown in the available literature earlier. These values demonstrate the development of secondary mitochondrial dysfunction in post-COVID-19 period in both younger and older age groups, particularly, in patients with more severe progression of BOS. Estimation of this parameter would allow to revealthe personified characteristics for each patients, which is important for quantifying the efficacy and duration of the required antioxidant therapy.

One of the important problems of medicine is the search for new reliable markers of inflammation that would allow us to determine the type of inflammatory process. The aim of the study was to identify specific markers of infectious and aseptic inflammation based on the analysis of morphological variants of neutrophil extracellular traps (NETs). The study included 26 patients with various nosological forms of inflammation in the abdominal cavity (12 with acute appendicitis, 8 with acute cholecystitis, 6 with a diagnosis of pancreatitis/ pancreonecrosis) after surgery. The study also included 20 patients with post-COVID and a group of 10 volunteers no clinical manifestations of the disease, but at the same time had contacts with flu patients. Neutrophils were isolated using gradient centrifugation. Fluorescence microscopies with the dye SYBR Green (JSC “Evrogen”, Russia) were used for NET visualization and counting. NETs in the morphological form of neutrophils web structure were found in the blood of surgical patients with acute appendicitis who had a favorable course of the postoperative period. In a group of volunteers who were exposed to influenza but did not have symptoms of an infectious disease, we also found neutrophils web structure. In all patients with abdominal inflammation complicated by abdominal abscess, in addition to neutrophil web structure, abnormal forms of NETs were recorded, in particular, NETs in the form of single filaments. In the post-COVID patients an absolute absence of neutrophilis web structure was revealed. In all post-COVID patients, NETs are found only in the form of single filaments. The results of subsequent experiments showed that collagen peptides are inducers of the formation of NETs in the form of single filaments. The detection of neutrophils web structure is a sign of an infectious inflammatory process. NETs in the morphological form of single filaments are markers of aseptic inflammation, as well as a sign of endothelial damage.

While pathogenic protists inhabiting the reproductive tract are well studied, the gastrointestinal (GI) tract contains a constitutive protist microbiota that is an integral part of the vertebrate microbiome. Currently, the effect of protozoan infections on the host immune system and their potential contribution to disruption of mucosal immune homeostasis are not well understood. Protists, along with bacteria and viruses, are permanent representatives of the human microbiota. The main attention of researchers is focused on studying their pathogenic role in gastrointestinal diseases. However, their role in symbiotic relationships with hosts is relatively little studied. It was previously shown that the closest human ortholog of mouse Trichomonas (Tritrichomonas spp.) is Trichomonas Dientamoeba fragilis, which can cause symptoms of inflammatory bowel disease. It is currently unclear whether Dientamoeba fragilis and other protist species such as Enteromonas spp., Entamoeba dispar are commensals, pathobionts, or pathogens of the human intestinal tract. Thus, information about the mutualistic relationships between protists, the gastrointestinal microbiota, and the immune system of mice can be used to understand host-protozoan relationships in humans. The data obtained allow us to evaluate the potential contribution of commensal protozoa in the formation of protective mechanisms of the mucous membrane of animals and humans. We have previously shown that antibiotic therapy leads to an increase in the number of Tritrichomonas spp. along with a reduction in bacteria in the gut of mice with a mutation in the Muc2 gene. A mutation in this gene leads to impaired formation of the intestinal mucosa in mice. Mice with a mutation in the Muc2 gene can be used as model to study human inflammatory bowel diseases (IBDs). In this work, we conducted a comparative study of the immunological status of Muc2^–/– mice harboring Tritrichomonas spp. after antibiotic therapy for 2 weeks followed by gavage of Lactobacillus johnsonii into mice and mice without introduction of probiotic microorganisms (self-recovery). Analysis of the main populations of lymphocytes in the blood, spleen and lymph nodes showed that the introduction of Lactobacillus johnsonii after antibiotic therapy leads to a significant increase in the population of T-lymphocytes in the blood and spleen, and an increase in the number of helper T cells in the lymph nodes of Muc2^–/– mice compared to mice without the addition of probiotic microorganisms.

Tuberculosis, a disease caused by the bacterium Mycobacterium tuberculosis, is a major public health concern. Innate and adaptive immunity provide robust defense against pathogens. However, M. tuberculosis, which co-evolved with humans, has acquired many mechanisms to evade the immune response and ensure its intracellular existence and long-term survival within the host. Moreover, emerging evidence suggests that this secretive bacterium can alter expression of regulatory noncoding RNAs (including microRNAs), leading to dysregulation of biological processes underlying tuberculosis pathogenesis. For example, miR-222-3p has been shown to regulate the functional reprogramming of macrophages and is involved in the regulation of host innate immunity. Previously, we demonstrated the important role of miR-222-3p as a biological marker of tuberculosis activity. To confirm their biological targets and understand their role in the pathogenesis of tuberculosis, many research groups are working to establish functional relationships between miRNA expression under different conditions and their actual biological action using molecular biology and bioinformatics methods. In the present study, we demonstrated the effect of miR-222-3p overexpression on several functions of human macrophages of monocytic origin activated with M. tuberculosis antigens in in vitro culture. Specifically, we found that miR-222-3p overexpression significantly decreased IL-6 and IFNγ expression and increased IL-1β and cxcl10 expression in cultures of uninfected macrophages. Infected macrophages overexpressing miR-222-3p were characterized by increased NF-κB and IL-6 expression, as were infected macrophages without transfection. Another important finding was that miR-222-3p overexpression caused a small but significant increase in reactive nitrogen species production by infected macrophages, but did not affect their bacteriostatic activity against M. tuberculosis. Elucidating the functions of different microRNAs in regulating different pathogenic pathways in TB may lead to discovering new therapeutic targets. The detailed study of microRNAs that regulate immune-associated pathways will be useful for the design of miRNA mimetic molecules, either as inhibitors or as activators. Immune effects induced by miRNA drugs are currently a major challenge for miRNA therapeutics.

Bacterial vaginosis is one of the most common reproductive health problems in women. Lactobacillus spp. play a leading role in the vaginal biocenosis and provide local antimicrobial defense, but not all species are equally capable of protecting the vaginal ecosystem from pathogens. Diagnostic methods in practical healthcare do not allow identification of Lactobacillus spp. species, which limits the ability to comprehensively assess the status of the vaginal biocenosis. We conducted a study in which we compared microscopy data of the examined smear with the detection of Lactobacillus spp. and other microorganisms. The aim of the study was to evaluate the species composition of Lactobacillus spp. from the vagina depending on morphologic characteristics and composition of associated flora. The study included 64 conditionally healthy women of reproductive age from 18 to 35 years old. The study of species composition of the vaginal biocenosis and typing of lactobacilli was carried out by real-time PCR methods. The obtained results were processed using generally accepted methods of descriptive and ordinal statistics. During the study, it was found that the vaginal biocenosis was dominated by species of Lactobacillus spp. L. crispatus, L. vaginalis, L. iners and L. jensenii. L. johnsonii was rarely found, and L. acidophilus was not detected. Typing results showed that the vagina was more frequently colonized by more than one species of Lactobacillus spp. while a single species of Lactobacillus spp. was detected less frequently. A correlation was found between Lactobacillus spp. species and bacilli thickness. If thick bacilli are detected in gynecological smear microscopy, they belong to the species L. crispatus, which has high colonization resistance and is a factor in the stability of the vaginal biocenosis. If smear microscopy reveals thin bacilli, then these are species of L. iners and L. jensenii. These representatives of Lactobacillus spp. are not directly related to the dysbiotic state of the vagina, but may indicate the possible development of dysbiosis in the future.

Shiga toxin-producing Escherichia coli (STEC) causes acute intestinal infections and also causes acute renal failure, especially in children. Shiga toxins (Stx) occupy a central place in the pathogenesis of hemolytic uremic syndrome (HUS) in Escherichiosis. The presented work analyzes the effectiveness of laboratory diagnostics of enterohemorrhagic escherichiosis in patients at the stage of manifestation of HUS and/or acute renal failure using microbiological, immunological research methods and PCR analysis. The study used clinical material from 30 patients in the pediatric intensive care unit of the St. Vladimir Children’s City Clinical Hospital in Moscow with symptoms of HUS aged from 8 months to 5 years. Blood sera from 20 healthy donors were used as control. As a result of PCR analysis, stx2 DNA was detected in 23.3% of cases. Bacteriological research made it possible to sow a pure culture of Escherichia coli O157:H7 in only 3.3% of cases. Since the development of HUS begins in patients with acute intestinal infection caused by Shiga toxin-producing microorganisms starting from the 5th day of the disease, when antibiotic therapy is already carried out, the bacteria can be completely destroyed, which makes it difficult to identify them by bacteriological methods, as well as to detect genes encoding Shiga toxin in PCR analysis. Typically, patients with HUS are admitted to the intensive care unit 5–7 days after the onset of the disease, when class G immunoglobulins specific to the pathogen are already beginning to circulate in the blood. In this regard, the use of immunological tests can be effective to confirm the diagnosis of STEC infection. In our studies, enzyme immunoassay allowed us to detect antibodies to Stx2A in 63.3% and to Stx2B in 43.3% of patients. Using immunoblotting, antibodies to Stx2A were detected in all sera obtained from patients and in 66.7% of cases to Stx2B. Immunoblot analysis was characterized by higher sensitivity for detecting antibodies to Stx2, however, due to the presence of an immunological layer among healthy people, it is preferable to use ELISA analysis. In healthy donors with antibodies to Stx2, the antibody titer was significantly lower than in patients. Laboratory confirmation of the diagnosis of STEC infection is difficult when conducting microbiological and molecular genetic studies, which is confirmed in this work. The effectiveness of laboratory diagnostics can be expanded by performing an ELISA aimed at detecting antibodies to Stx2A.

To increase the effectiveness and immunogenicity of modern vaccines, especially subunit ones, it is required to use adjuvants. Polysaccharides, due to their safety and biocompatibility, are desirable candidates for the creation of vaccine adjuvants. The aim of our study was to develop a method for obtaining beta-Glucans from the yeast Saccharomyces cerevisiae cell wall, and evaluate their adjuvant properties. The high purity and non-toxicity of the resulting preparation was achieved by using enzyme complexes of cellulase and protease in combination with ultrasound (22 kHz) at the purification stage. The developed scheme allows for the yield of beta-Glucans up to 2 g from 100 g of the biomass of wet cells. The adjuvant properties of beta-Glucans were studied in 50 male BALB/c mice, weighing 16–18 g. Immunization was performed twice, with a 14-day interval, intramuscularly, 200 μl per animal. The recombinant receptor-binding domain (RBD) of the surface S protein of the SARS-CoV-2 virus (Wuhan-Hu-1 and B.1.617.2 (Delta)) was used as an antigen, at a dose of 50 μg per animal. A positive control group was administered with the antigen combined with aluminum hydroxide. As a negative control, mice injected with the saline solution were used. The titers of specific antibodies in the blood sera were determined by ELISA assays. RBD (Wuhan-Hu-1 and Delta), and S protein (Wuhan-Hu-1, Delta and Omicron) were used as antigens. The titers of virus-neutralizing antibodies were measured in neutralization tests using SARS-CoV-2 virus strains Wuhan-Hu-1, Delta (B.1.617.2) and Omicron (B.1.1.529). The results of the study have shown that beta-Glucans have the ability to enhance the production of specific and virus-neutralizing antibodies in mice immunized with RBD. The titers of specific and virus neutralizing antibodies are comparable to their levels in the group immunized with RBD and Al(OH)₃. It has been found in the experiments in white outbred ICR mice that the preparation belongs to practically non-toxic substances. Therefore, it can be concluded that the use of beta-Glucans could become a preferable alternative to the conventional adjuvants based on aluminum salts, being biocompatible, biodegradable and non-toxic substances of low labor-intensive production.

Introduction. Rubella virus is an RNA-containing virus capable of infecting human cells and causing infectious disease. Infection of pregnant women with rubella virus can lead to abortion or congenital rubella syndrome (CRS), a set of long-term birth defects including incomplete fetal organ development and mental retardation. There is no specific treatment for rubella and CRS. The regulation of antiviral immune response and viral reproduction by long non-coding RNAs is currently under active investigation. In this study, we evaluated the changes in the expression profile of long non-coding RNAs in rubella virus-infected A549 epithelial by RNA sequencing. Materials and Methods. A549 cells were infected with a wild-type variant of laboratory strain C-77 of rubella virus with a multiplicity of infection of 1.0 infectious units per cell and incubated for 72 hours. Virus titres were determined by the CCID method in the sensitive RK-13 cell culture. 48 h after infection, the cell monolayer was lysed, RNA was isolated, and libraries were prepared for sequencing. Sequencing was performed on the NextSeq500 platform (Illumina, USA) in paired-end reading mode. Validation of the obtained RNA sequencing data was performed using quantitative real-time PCR. Results. Rubella virus replication affects the production of some long non-coding RNAs by altering their expression profile. Thus, upon infection of A549 epithelial cells with rubella virus, there was a significant increase in the expression of such long non-coding RNAs as GAS5, NEAT1, LUCAT1, MIR210HG, MEG3, EPB41L4A-AS1, ZFAS1, and SNHG 1, 7, 12, 29, 32. DANCR, IGFL2-AS1, IGFL2-AS1, MIR1915HG, and SNHG14 were most significantly decreased in expression. Gene ontology (GO)-analysis revealed that long non-coding RNAs are involved at different levels in the mechanisms of immune response, in particular, RNA processing and nucleic acid metabolism; therefore, up- and down-regulation of these molecules leads to modulation of human antiviral immune response in response to rubella virus infection. Conclusion. Thus, the regulation of long non-coding RNA production by rubella virus has been shown for the first time. Differentially expressed long non-coding RNAs can be used as prognostic and diagnostic biomarkers of viral diseases.

Introduction. Influenza is a disease caused by a widespread virus with pandemic potential. Frequently, individuals vaccinated against seasonal influenza virus are still susceptible to the disease, indicating the need to improve the immunogenic potential of existing vaccines. To assess the efficacy of influenza virus vaccines, immune response only to a single viral antigen — hemagglutinin molecule, is taken into consideration. However, according to preclinical and clinical studies, neuraminidase (NA) stimulates cross-protective immunity, which is effective against not only homologous but also drifted variants of influenza A virus. Materials and methods. In the present study, we investigated the ability of previously selected conserved linear B-cell NA epitopes (SGYSGK, SWPDGK, EECSCYPK, VELIRGRK) to enhance the immunogenicity of an inactivated whole-virion influenza vaccine based on the model strain PR8 (iPR8). BALB/c mice were injected with iPR8 in combination with one of the peptides intramuscularly three times at two-week intervals. Blood samples were collected 14 days after the last immunization, after which the mice were challenged with heterosubtypic influenza viruses H1N1pdm09 and H3N2. Results. All immunized mice showed induction of H1N1 (PR8)-specific IgG antibodies two weeks after the third immunization. The group of mice immunized with the iPR8 vaccine preparation in combination with VELIRGRK peptide showed the most pronounced induction of IgG antibodies to the H6N1 reassortant strain, the NA of which corresponds to the iPR8 virus, indicating the ability of the NA peptide to stimulate the production of NA-specific antibodies. However, the antibodies produced after immunization were not capable to inhibit the NA enzymatic activity. Despite this, mice immunized with iPR8 in combination with anti-NA peptides showed a higher survival rate after infection with heterologous virulent influenza viruses: A/California/07/09 (H1N1pdm09) and A/Philippines/2/82 (H3N2) compared to the PBS and iPR8 groups. Conclusion. Thus, the study demonstrated the immune-potentiating effect of individual peptides corresponding to conservative linear epitopes of the NA molecule in combination with a standard inactivated influenza vaccine, which made it possible to improve the protective effect of the vaccine against heterosubtypic influenza viruses.

Hepatitis B is an infectious disease resulting from infection with the hepatitis B virus. Chronic hepatitis B (CHB) is characterized by prolonged inflammation in the liver, the development of fibrosis, liver cirrhosis and hepatocellular carcinoma. Factors of the immune system play a critical role in the pathogenesis of CHB. Thanks to chemokines, immune cells migrate to the site of inflammation to implement their effector functions. The CX3CL1/Fractalkine chemokine is the only member of the CX3C family of chemokines with unique structural and functional properties. Its receptor CX3CR1 is expressed mainly on the surface of cytotoxic effector lymphocytes such as NK cells, TNK and cytotoxic T lymphocytes. The purpose of our study was to analyze the content of CX3CL1/Fractalkine in the blood plasma of patients with CHB and the analysis of this chemokine with liver fibrosis. The concentration of CX3CL1/Fractalkine was determined in the blood plasma of patients with CHB using a multiplex assay based on xMAP technology. Blood plasma from patients with chronic viral hepatitis C (CHC) and autoimmune liver diseases (AILD) was used as a comparison group. The control group consisted of healthy individuals. For statistical analysis of data, nonparametric statistics methods were used: Kruskal–Wallis test, Spearman correlation coefficient ROC-analysis. It was shown a reduced level of CX3CL1/Fractalkine in patients with CHB compared with the control group (p = 0.0003) and with the comparison groups of CHC (p < 0.0001) and AILD (p = 0.0005). A reduced concentration of CX3CL1/Fractalkine was shown in the blood plasma of CHB patients with initial fibrosis (p = 0.0092) and severe fibrosis/cirrhosis (p = 0.0009), while in patients with severe fibrosis/cirrhosis, a significantly reduced level of this chemokine was established compared with the initial degree of liver fibrosis (p = 0.0081). Correlation analysis revealed a highly significant inverse relationship between the severity of liver fibrosis and the content of CX3CL1/Fractalkine in the blood plasma of patients with CHB (Spearman r = –0.33; p = 0.02). Thus, the chemokine CX3CL1/Fractalkine is included in the immunopathogenesis of CHB; its reduced content is characteristic only of CHB and does not change in other chronic liver diseases. It is involved in the processes of liver fibrosis during infection with the hepatitis B virus. The concentration of the chemokine CX3CL1/Fractalkine depends on the stage of liver fibrosis in CHB, and a decrease in the level of CX3CL1/Fractalkine in the blood plasma can serve as a negative factor in the development of CHB.

Introduction. The problem of treating patients with respiratory allergopathology associated with recurrent infectious diseases, such as rARVI, frequent exacerbations of rCHVI, is becoming urgent. The presence of persistent inflammation and co-infection significantly complicates the treatment of immunocompromised patients with year-round allergic rhinitis (YAR) and necessitates the development of personalized programs, with the inclusion of immunomodulatory agents for restoring disorders in the immune system (IS) and interferon system (IFN). Materials and methods. The study group (SG) included 65 patients of both sexes aged 23–60 years, suffering from YAR associated with rARVI and rCHVI. The comparison group (CG) consisted of 50 healthy individuals, comparable in sex and age. All patients underwent standard physical, immunological and allergological examinations, including the use of serological (ELISA, ImmunoCUP), molecular genetic (PCR-RV) methods, FC, etc. Voluntary informed consent was obtained from all patients. The StatPlus computer program was used for statistical analysis. Results and discussion. In patients with YAR associated with rARVI and rCHVI, two variants of disorders in IS have been established, which are defined as pathological immunophenotypes (PIF). The PIF1 is characterized by a deficiency in the induced production of IFNα, a decrease in CD3⁻CD16⁺CD56⁺ EKKs, and a decrease in neutrophil granulocytes (NG). In the PIF2, along with a shortage of IFNα production, a decrease in EKKs is observed in combination with a decrease in CTLs, as well as a decrease in NGs. The clinical criteria for immunocompromising in this cohort of patients were studied. The severity of YAR symptoms was assessed by VAS. In order to correct the identified disorders in the IS and IFN system, complex personified IFN- and immunotherapy programs have been developed for each PIF, including prolonged local and systemic therapy with rIFNα2b in combination with antioxidants, as well as GMDP for patients of SG1, and for patients of SG2 — GMDP and hexapeptide. The high immunological and clinical efficacy of IFN- and immunotherapy was shown, which was expressed in the tendency to restore existing disorders, as well as in achieving control over the symptoms of YAR, with the possibility of reducing the volume of basic antiallergic pharmacotherapy.