The presence and restriction fragment length polymorphism (RFLP) of DNA fragments hybridizing with virulence and "house keeping" gene probes were analyzed for 87 group B streptococcal (GBS) strains of human and bovine origin. Most characteristics obtained for bovine strains were similar when compared with those for human strains. The most significant degree of RFLP was discovered for the sizes of HindIII fragments containing bca gene. Human GBS strains with bac gene, encoding beta antigen with IgA binding capacity, were characterized by almost identical complex hybridization patterns with multiple gene probes. At the same time bac gene was not found among bovine GBS strains. Gene scpB that encodes C5a peptidase in all human GBS strains was detected only in 9 of 39 strains of bovine origin. These two characteristics effectively distinguished bovine GBS strains from GBS strains of human origin.

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We studied the expression of some CC chemokines and their receptors in the synovium of patients with rheumatoid arthritis, osteoarthrosis, and a history of joint injury. In patients with rheumatoid arthritis, the levels mRNA for some angiogenic and proinflammatory chemokines (CCL5/RANTES, CCL11/eotaxin, CCL24/eotaxin-2, and CCL26/eotaxin-3) and their receptors (CCR1, CCR2, CCR3, CCR4, and CCR5) was elevated. mRNA expression correlated with activity, stage, and serological status of rheumatoid arthritis. Obtained data confirm the importance of CC chemokines as mediators of angiogenesis and inflammation in the synovium in rheumatoid arthritis.

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We performed a comprehensive analysis of CCR6 and CXCR3 chemokine receptors and their ligands CCL20/MIP-3α, CXCL9/MIG, CXCL10/IP-10, and CXCL11/ITAC in the liver and blood of patients with chronic hepatitis C at different stages of the disease. TaqMan PCR was used to determine mRNA gene expression of chemokines and their receptors in liver specimens, xMAP multiplex analysis was performed to estimate the concentration of chemokines in blood plasma, and fl ow cytofluorometry was used to evaluate CCR6 and CXCR3 expression on peripheral blood lymphocyte populations. In the liver of patients with hepatitis C, mRNA expression of CXCL10, CCR6, and CXCR3 genes increases with fibrosis progression in the liver tissue. In the plasma, concentrations of all studied chemokines increased depending on the stage of liver fibrosis, CCR6 and CXCR3 expression was changed in various lymphocyte populations. Thus, chemokines are involved in the immunopathogenesis and fibrogenesis in chronic viral hepatitis C. The results suggest using these chemokines in the diagnosis and prognosis of the disease.

The global community is experiencing one of the largest infectious disease outbreaks in the 21st century. In the Saratov Region, the first case of new coronavirus infection was confirmed on March 19, 2020.The maximum increase in cases was noted between May 15 and June 30, during that time the total number of infected people in the region increased from 1526 to 6444. Since July 2020, a stable incidence level of new coronavirus infection has been observed in the Saratov Region, without a steady decline.The aim of the study was to assess the status of population immunity to the SARS-CoV-2 virus among residents of Saratov and the Saratov Region under the COVID-19 epidemic.Materials and methods. In the period from June 23 to July 26, 2020, a serological study of blood samples from 3372 volunteers of different age groups was conducted. The content of antibodies to SARS-CoV-2 was determined by ELISA using a set of reagents “ELISA anti-SARS-CoV-2 IgG” produced by the State Scientific Center of Applied Microbiology and Biotechnology of the Rospotrebnadzor (Russia).Results and discussion. In general, the incidence of COVID-19 in the Saratov Region is taking place against the background of moderate seroprevalence to the SARS-CoV-2 virus, accompanied by a high incidence of non-apparent (asymptomatic) forms of the infectious process. The absence of clinical symptoms of the disease, in the context of the limited use of methods for determining the RNA of the SARS-CoV-2 virus in PCR (11 % of the region’s population) makes it difficult to assess the real spread of the virus in the population and to establish the timing of the formation of persistent herd immunity. A low rate of antibody response among individuals with a positive result of PCR analysis, as well as among volunteers who had an infection in May, June 2020, indicates a weak formation of the immune response, or the prevalence of individuals reacting mainly by activating the cellular link of the immune system in the population. The obtained results, although they need to be explained in a number of respects, can be applied to the organization of preventive measures, including vaccination, in the region.

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Different fragments of the bac gene coding for the IgA-binding protein were cloned, sequenced and expressed in E. coli. Cloning was accomplished after amplification of different parts of the gene by PCR. The 1.5-kb fragment of the gene was cloned using plasmid pBluescript. This fragment coded for the 45-kDa protein with the stable expression of IgA binding. In order to verify the exact location of the IgA-binding domain two smaller plasmids were constructed. Both plasmids were prepared using pQE30 (31, 32) expression vectors from Qiagen. The plasmids carried 245 and 123 bp bac gene fragments encoding 14- and 7-kDa proteins. These proteins together with the 20-amino-acid oligopeptide ITNEDKDSMLKKIEDINRQA were tested for IgA binding. Only the 14-kDa protein was able to bind IgA. This protein was used for rabbit immunization and found to be immunogenic. The data obtained lead to the conclusion that there is a lower limit in the size of recombinant IgA-binding proteins that can be utilized for anti-GBS vaccination.