Natalia A. Nikitenko

Introduction. Adenovirus infection occurs globally in the form of sporadic cases and isolated outbreaks. Human adenovirus type 55 (HAdV-55), endemic in China and South Korea, causes acute respiratory viral infections (ARVI) of varying severity, both among the civilian population and in military units in different countries of the world. Genomic research facilitates reliable identification of HAdV-55. The aim of this study was to identify HAdV isolated in Moscow in 2022, as well as to conduct whole-genome sequencing and comparative genomic research. Materials and methods. HAdV-55 was isolated from a sample of a patient hospitalized with pneumonia and analyzed using restriction fragment length polymorphism analysis and whole-genome sequencing. Bioinformatics comparative analysis was performed on a sample of sequences of 83 isolates. Results. The whole-genome sequencing of first isolated in Russia HAdV-55 was conducted. The sequence of isolate SCV3008:Ad55 was deposited in GenBank (Accession Number PQ641625). Unique mutations in the SCV3008:Ad55 genome were identified, one of which resulted in a conservative T29A substitution in the penton that did not affect its functions. Phylogenetic analysis showed clustering of SCV3008:Ad55 with isolates of clade II, which included representatives of 7 countries on different continents, indicating a wide distribution of HAdV-55. Isolates from endemic regions of China and South Korea formed separate clades. The study of microsatellite length polymorphism in untranslated regions of the genome became an additional tool for distinguishing closely related genomes. Conclusion. The obtained genomic information laid the foundation for further monitoring for HAdV-55 in Russia and demonstrated the informativeness and significance of whole-genome studies for monitoring adenoviruses. The development and implementation of genotyping methods aimed at detecting HAdV-55 and other clinically relevant genotypes will significantly improve the effectiveness of the diagnosis of adenovirus infections with the threat of developing bronchopneumonia.

Introduction. COVID-19 is characterized by a varied clinical course. The aim of the work was to identify associations of SNPs of hemostatic system genes with COVID-19. Materials and methods. DNA was isolated from patients (n=117) and healthy participants (n=104). All infected patients were divided into 3 groups, depending on disease severity assessment, which was appreciated by NEWS2. Another group consisted of participants, who had asymptomatic infection in the past. Determination of SNPs of the genes FGB (-455 G/A), FII (20210 G/A), FV (1691 G/A), FVII (10976 G/A), FXIIIA1 (103 G/T), ITGA2 (807 C/T), ITGB3 (1565 T/C), SERPINE1 (-675 5G/4G) were performed by PCR using the “Genetics of Hemostasis” kit (“DNA-Technology”, Russia). Results. In analyzed SNPs, no significant differences were detected between the group of infected patients and healthy participants. But significant association was revealed in gene SERPINE1 (-675 5G/4G), when patient groups, differing in the disease severity, were analyzed relative to the group of participants with asymptomatic infection (p=0.0381; p=0 .0066; p=0.0009). It was found, that as COVID-19 severity scores increased, the proportion of 5G allele of gene SERPINE1 decreased, and the proportion of the 4G allele increased (p=0.005; p=0.009; p=0.0005). Similar processes were observed for genotypes 5G/5G and 4G/4G. Discussion. The gene SERPINE1 (-675 5G/4G) is associated with the severity of COVID-19. Conclusion. For the first time, it was discovered that 5G/5G genotype of gene SERPINE1 (-675 5G/4G) can be a marker of a milder course of COVID-19, and the 4G/4G genotype as a more severe one.

The main cause of death in patients with cystic fibrosis (CF) is infectious process in the lungs, in particular, chronic lung infections caused by various pathogens, most often a combination of bacteria, fungi, or viruses. Data on mixed bacterial and viral-bacterial infections from domestic and foreign sources are fragmentary and sparse. The dominant associations of bacterial and viral pathogens in patients with cystic fibrosis have not been studied properly, and data on their epidemiological significance are lacking. The aim of this study was to assess the prevalence of bacterial and viral infections in patients with cystic fibrosis and to substantiate the need for the development of virological monitoring. Methods. Biomaterials from the respiratory tract of CF patients (409 children and 160 adults with CF) examined from 2006 to 2022 were used. The study was carried out using bacteriological methods, molecular genetic methods (RT-PCR) and MALDI-TOF mass-spectrometry. Results. Microflora of the respiratory tract was shown to be mixed in 2/3 patients with CF. The microflora of the lungs of children with CF is a dynamic community of microorganisms with high diversity and variability. In adult patients, associations of microorganisms are more common than in children, but the composition of associations is less diverse. We isolated about 40 species of bacteria from adult patients and more than 85 species from children in our sample. NFMO prevailed, including Burkholderia cepacia complex, Pseudomonas aeruginosa, Achromobacter xylosoxidans, Achromobacter ruhlandii, Stenotrophomonas maltophilia, and Staphylococcus aureus, Candida albicans, Aspergillus spp. Real-time PCR showed the presence of rhinovirus RNA in 10% of samples obtained from children and 12.9% from adults with cystic fibrosis. Conclusion. Our results indicate the need for continuous monitoring of the lung microflora in patients with CF, including testing for viruses.

Induction of a robust and long-lived mucosal immune response during vaccination is critical to achieve protection against numerous pathogens. However, traditional injected vaccines are generally poor inducers of mucosal immunity. One of the effective strategies to improve vaccine efficacy is incorporation of adjuvant molecules that enhance and polarize adaptive immune reactions. Effects of Syk-coupled lectin receptor agonists as adjuvants to induce mucosal immune reactions during parenteral immunization are not fully studied. We now report that the agonists trehalose-6,6-dibehenate (TDB), curdlan, and furfurman, which stimulate Dectin-1, Dectin-2, and Mincle, respectively, activate transcription factors (NF-κB, NFAT, and AP-1) to various extents in murine RAW 264.7 macrophages, even though similar pathways are activated. The agonists also elicit differential expression of maturation markers in bone marrow-derived dendritic cells, as well as differential cytokine secretion from these cells and from splenic mononuclear cells. In vivo assays also show that agonists of Dectin-1 and Dectin-2, but not Mincle, induce heavy IgA secretion in intestinal mucosa even when delivered parenterally. Strikingly, this effect appears to be formulation-independent. Collectively, the data suggest that adjuvants based on Dectin-1 and Dectin-2 agonists may significantly improve the efficacy of parenteral vaccines by inducing robust local immune reactions in intestinal mucosa.