Most species of the genus Bifidobacterium contain the gene cluster PFNA, which is presumably involved in the species-specific communication between bacteria and their hosts. The gene cluster PFNA consists of five genes including fn3 , which codes for a protein containing two fibronectin type III domains. Each fibronectin domain contains sites similar to cytokine-binding sites of human receptors. Based on this finding we assumed that this protein would bind specifically to human cytokines in vitro . We cloned a fragment of the fn3 gene (1503 bp; 501 aa) containing two fibronectin domains, from the strain B. longum subsp. longum GT15. After cloning the fragment into the expression vector pET16b and expressing it in E. coli , the protein product was purified to a homogenous state for further analysis. Using the immunoferment method, we tested the purified fragment’s ability to bind the following human cytokines: IL-1β, IL-6, IL-10, TNFα. We developed a sandwich ELISA system to detect any specific interactions between the purified protein and any of the studied cytokines. We found that the purified protein fragment only binds to TNFα.

Introduction. The increase in the incidence of whooping cough in children and adults of different age groups justifies the need for their revaccination and the development of new, acceptable for these purposes. This work is devoted to substantiating the design of a clinical trial and describing the results of a comparative study of the safety and tolerability of the drug "GamLPV" with two-fold intranasal administration to healthy adult volunteers using two methods. The choice of the scheme and method of administration of the drug is justified. The serological structure of the population of adults aged 18–40 years living in Moscow and the Moscow region is characterized.Aim. Determination of the safety and tolerability of the drug with a double intranasal administration of the vaccine by drip method and spraying through an actuator.Materials and methods. A randomized placebo-controlled trial included 50 healthy male and female volunteers aged 18 to 40 years who met the inclusion criteria. The volunteers were divided into 2 groups of 25 people: a drip method of administration and spraying through an "actuator". By both methods, the drug was administered twice with an interval of 60 days.Results and discussion. Serological analysis of the population of healthy volunteers at the prescreening stage justified the inclusion in the study of volunteers containing anti-pertussis antibodies in the blood (IgG ≤40 Ed/ml). A comparison of the results of preclinical studies on an experimental model of non-human monkeys and the first phase of a clinical study of GamLPV allowed us to propose two methods of double administration of the drug as a promising vaccination scheme for volunteers. A comparative randomized study shows the safety of using the proposed scheme for vaccination of adult volunteers.Conclusions. Both proposed methods of double administration can be used to plan a multicenter study to research the immunogenicity and protective activity of GamLPV.

In the midst of continuing coronavirus infection (COVID-19) there has been an increase in the incidence of various autoimmune pathologies. Particular attention to the potential relationship between coronavirus infection and autoimmune diseases is attracted by the positive therapeutic effect of the treatment of severe forms of COVID-19 with drugs used in the treatment of rheumatologically diseases.The results of the study should be the starting point for understanding the mechanisms of possible breakdown of immunological tolerance and the development of autoimmune thyroid diseases.AIM: To assess the risks of developing autoimmune thyroid disease after COVID-19, and to investigate the effect of therapy in the acute period on the possible development of autoimmune thyroid diseases.MATERIALS AND METHODS: This prospective comparative study included patients hospitalized at the National Medical Research Center for Endocrinology with a clinical and laboratory analysis of COVID-19 and bilateral polysegmental viral pneumonia (n=41). Patients with COVID-19 were divided into two subgroups: a subgroup of patients who received tocilizumab therapy in acute period (n=10), the second subgroup of patients who received symptomatic therapy during the acute period COVID-19 (n=31).To assess the functional status of the thyroid gland all patients underwent observation of the thyroid-stimulating hormone (TSH), free triiodothyronine (T3f), free thyroxine (T4f), antibodies to thyroperoxidase (Ab-TPO) and antibodies to the TSH receptor (Ab-recTSH).The concentrations of 27 signaling molecules in the blood serum were assessed by the technology of multiplex flow immunoassay using the Bio-Plex Pro Human Cytokine 27-plex Assay kit of cytokines and chemokines: interleukins-1b, -1ra, -2, 4-10, -12, -13, -15, -17 (IL-1b, IL-1ra, IL-2, IL - 4-10, IL-12, IL-13, IL-15, IL-17), Eotaxin, fibroblast growth factor (FGF), granulocyte- macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor (G -CSF), interferon-gamma (IFN-g), IFNγ-inducible protein 10 (IP-10), monocyte chemotactic protein-1 (MCP-1), also known as monocyte chemotactic and activating factor (MCAF), macrophage inflammatory protein -1 (MIP-1a and -1b), platelet growth factor BB (PDGF-bb), Regulated on Activation Normal T-cell Expressed and Secreted (RANTES), tumor necrosis factor-alpha (TNF-a), vascular endothelial growth factor (VEGF).All patients denied the presence of thyroid diseases, palpation of the thyroid gland revealed nodular formations in 5% of patients, and appropriate recommendations were given to patients.RESULTS: The overt hypothyroidism was detected in 2.4% of patients, subclinical - in 7.3% of patients in six months after the onset of coronavirus infection, and also found increased levels of the Ab-TPO in six months after recovery (p = 0.023 - Wilcoxon test). In the group of patients with increased Ab-TPO levels after COVID-19, statistically significantly high levels of IFN-g (p = 0.007), Eotaxin (p = 0.008) were obtained. An increased Ab-recTSH were revealed in the group of patients with severe COVID-19 who did not receive pathogenetic therapy with tocilizumab in the acute period (p = 0.046 - Mann-Whitney test).CONCLUSION: The results of our study and the scientific work of foreign colleagues demonstrate the potential risks of developing autoimmune thyroid diseases after a coronavirus infection. A close relationship was found between changes in the thyroid profile and hyperactivation of the immune system with hyperproduction of pro-inflammatory interleukins in COVID-19. This statement is confirmed by the revealed overt and subclinical hypothyroidism, as well as an increase in Ab- TPO levels in this group of patients after a coronavirus infection (p = 0.023 - Wilcoxon test) with a simultaneous persistent increased levels of some pro-inflammatory cytokines in dynamics, determined by autoimmune thyroiditis.The hypothesis of thyroid tissue damage by pro-inflammatory cytokines during COVID-19, as well as the hypothesis suggesting a protective effect on the development of autoimmune thyroid diseases by therapy with tocilizumab in the acute period were confirmed by increased levels of Ab-recTSH in patients with severe COVID-19 who did not receive tocilizumab in the acute period (p = 0.046 - Mann-Whitney test).

Introduction. A significant increase in the incidence of pertussis in the world, including among adolescents and adults, the prevalence of mild forms of the disease and asymptomatic carrier of bacteria B. pertussis, and the resulting need for mass revaccination of different age groups determine the demand for new vaccines against B. pertussis. In N.F. Gamaleya Federal Research Center for Epidemiology and Microbiology, a live intranasal pertussis vaccine for the prevention of pertussis (GamLPV) has been developed. The GamLPV vaccine underwent preclinical studies that proved its safety and effectiveness in experiments on small laboratory animals and nonhuman monkeys. Safety of vaccine is shown in clinical studies on healthy volunteers.The aim of the study is to assess the immunogenicity of different doses of the drug GamLPV when first used in healthy volunteers.Materials and methods. The study was conducted as randomized placebo-controlled, blind trial with consistent volunteer inclusion and dose escalation. Study ID in clinicaltrials.gov database: NCT03137927 (A Phase I Clinical Study of a GamLPV, a Live Intranasal Bordetella Pertussis Vaccine). The following parameters of humoral and cellular immune responses were assessed in dynamics: levels of specific IgM, IgG and IgA antibodies in blood serum of volunteers and the number of cytokines interleukin-17, tumor necrosis factor-α, interferon-γ produced after specific induction in vitro of blood mononuclears of vaccinated volunteers. Dynamics of attenuated bacteria persistence in nasopharynx of vaccinated volunteers was evaluated.Results. Intranasal vaccination of volunteers with the drug Gam LPV resulted in the formation of a specific humoral (IgG and IgA) and cellular immune response. The dose-dependent nature of immunoglobulin and cytokine production was shown. Attenuated bacteria persisted for a long time in the nose/oropharynx of vaccinated volunteers.Discussion. Good tolerability of all tested doses of the drug justifies the choice for further investigation of a vaccine dose equal to 4 × 109 CFU. At the next stage, the safety and immunogenicity of two-time vaccination of volunteers will be studied.

Aim: This study is mainly devoted to determining the ability of ∆FN3.1 protein fragments of Bifidobacterium (B.) longum subsp. longum GT15, namely two FN3 domains (2D FN3) and a C-terminal domain (CD FN3), to bind to tumor necrosis factor-alpha (TNF-α). Methods: Fragments of the fn3 gene encoding the 2D FN3 and CD FN3 were cloned in Escherichia (E.) coli. In order to assess the binding specificity between 2D FN3 and CD FN3 to TNFα, we employed the previously developed sandwich ELISA system to detect any specific interactions between the purified protein and any of the studied cytokines. The trRosetta software was used to build 3D models of the ∆FN3.1, 2D FN3, and CD FN3 proteins. The detection of polymorphism in the amino acid sequences of the studied proteins and the analysis of human gut-derived bacterial proteins carrying FN3 domains were performed in silico. Results: We experimentally showed that neither 2D FN3 nor CD FN3 alone can bind to TNFα. Prediction of the 3D structures of ΔFN3.1, 2D FN3, and CD FN3 suggested that only ΔFN3.1 can form a pocket allowing binding with TNFα to occur. Polymorphism analysis of amino acid sequences of ΔFN3.1 proteins in B. longum strains uncovered substitutions that can alter the conformation of the spatial structure of the ΔFN3.1 protein. We also analyzed human gut-derived bacterial proteins harboring FN3 domains which allowed us to differentiate between those containing motifs of cytokine receptors (MCRs) in their FN3 domains and those lacking them. Conclusion: Only the complete ∆FN3.1 protein can selectively bind to TNFα. Analysis of 3D models of the 2D FN3, CD FN3, and ΔFN3.1 proteins showed that only the ΔFN3.1 protein is potentially capable of forming a pocket allowing TNFα binding to occur. Only FN3 domains containing MCRs exhibited sequence homology with FN3 domains of human proteins.