Relevance. The worldwide use of pneumococcal vaccines, in particular conjugated vaccines (PCV), has led to a significant reduction in the incidence of invasive pneumococcal diseases in both vaccinated children and unvaccinated people of all ages. However, "non-vaccine" serotypes and capsule-free (non-typed) strains have become the main causes of pneumococcal disease, as with carriage, with an increase in antibiotic resistance. This requires new approaches in the development of vaccines that can lead to serotype-independent protection, especially in children, the elderly and immunocompromised people. The pneumococcal vaccine should protect against a wide range of serotypes, induce mucosal and systemic immunity, and reduce primary nasal colonization, as well as invasive forms. Aim. The review is devoted to the analysis of experimental development of innovative vaccines based on protective protein antigens (PPV), including in combination with capsular polysaccharides, using adjuvants or antigen delivery systems, as well as inactivated whole cell preparations (WCV) and live attenuated vaccines. Particular attention is paid to the methods of mucosal immunization, taking into account the tropism of pneumococcus in relation to the mucous membranes of the upper and lower respiratory tract. Conclusion. At this stage, the most developed and promising are drugs based on bacterial lysates (PWCV) and protective protein antigens (PspA, dPly), as well as these antigens mixed with adjuvants, and, possibly, with some etiologically most significant capsular polysaccharides.

Dendritic cells as the most active and highly specialized antigen presenting cells, play a key role in initiating immune responses. Currently, generation of medications activating dendritic cells for development of anti-infective and anticancer vaccines is of highly relevance. Preparations of microbial origin are promising to augment activity of dendritic cells, because they carry innate immune ligands for Toll-like receptors. Such preparations include experimental protein-containing pneumococcal preparations, obtained from acetone-inactivated microbial mass of the deposited S. pneumoniae 6B vaccine strain No. 296, followed by aqueous extraction and separation of 30—100 kDa fraction. Dendritic cells were obtained from bone marrow cells of CBA mice (n = 15), and cultured in complete growth medium RPMI-1640 added with recombinant GM-CSF and IL-4 (Biosource, USA). On day 6, experimental protein-containing pneumococcal preparations (50 pl/ml) were administered to the cultured immature dendritic cells. Commercial TNFa (20 ng/ml, Biosource, USA) was used as a standard maturation inducer (positive control). Immunophenotyping of dendritic cells was conducted by using flow cytometry with FITC- and PE-labeled monoclonal antibodies against cell surface receptors: CD34, CD38, CD83, CD86, CD80, CD11c, MHC II, CD14, CD282 (TLR2), CD284 (TLR4), (eBioscience, USA). Studying an effect of preparations on maturation of dendritic cells revealed that morphological characteristics of dendritic cells generated by using experimental protein-containing preparations did not differ significantly between each other as well as those induced by TNFα. The cells were characterized by large sizes, oval or irregular shape, veiled cytoplasm, eccentrically located nucleus and numerous long thin protrusions. Experimental proteincontaining preparations induced in cultured dendritic cells decrease in count of CD34+ immature and TLR2/TLR4+ cells, increased count of cells expressing markers of adhesion (CD38+), activation (MHC II+), costimulation (CD80/ CD86+) and terminal differentiation (CD83+), which may evidence about events of differentiation upon dendritic cell maturation. The 30—100 kDa fraction increased count of cells expressing adhesion molecules to a greater extent than aqueous extract that more pronouncedly stimulated rise in count of dendritic cells bearing costimulatory molecules (p < 0.05). The activity of the examined proteins regarding their effect on CD83+ cells was comparable. Experimental protein-containing antigens derived from pneumococcal vaccine strain were shown to induce maturation of dendritic cells from bone marrow precursors, induce a decrease in the count of TLR2 and TLR4-expressing cells accounting for activating effect on innate immune effectors.

Dendritic cells as the most active and highly specialized antigen presenting cells, play a key role in initiating immune responses. Currently, generation of medications activating dendritic cells for development of anti-infective and anticancer vaccines is of highly relevance. Preparations of microbial origin are promising to augment activity of dendritic cells, because they carry innate immune ligands for Toll-like receptors. Such preparations include experimental protein-containing pneumococcal preparations, obtained from acetone-inactivated microbial mass of the deposited S. pneumoniae 6B vaccine strain No. 296, followed by aqueous extraction and separation of 30—100 kDa fraction. Dendritic cells were obtained from bone marrow cells of CBA mice (n = 15), and cultured in complete growth medium RPMI-1640 added with recombinant GM-CSF and IL-4 (Biosource, USA). On day 6, experimental protein-containing pneumococcal preparations (50 pl/ml) were administered to the cultured immature dendritic cells. Commercial TNFa (20 ng/ml, Biosource, USA) was used as a standard maturation inducer (positive control). Immunophenotyping of dendritic cells was conducted by using flow cytometry with FITC- and PE-labeled monoclonal antibodies against cell surface receptors: CD34, CD38, CD83, CD86, CD80, CD11c, MHC II, CD14, CD282 (TLR2), CD284 (TLR4), (eBioscience, USA). Studying an effect of preparations on maturation of dendritic cells revealed that morphological characteristics of dendritic cells generated by using experimental protein-containing preparations did not differ significantly between each other as well as those induced by TNFα. The cells were characterized by large sizes, oval or irregular shape, veiled cytoplasm, eccentrically located nucleus and numerous long thin protrusions. Experimental proteincontaining preparations induced in cultured dendritic cells decrease in count of CD34+ immature and TLR2/TLR4+ cells, increased count of cells expressing markers of adhesion (CD38+), activation (MHC II+), costimulation (CD80/ CD86+) and terminal differentiation (CD83+), which may evidence about events of differentiation upon dendritic cell maturation. The 30—100 kDa fraction increased count of cells expressing adhesion molecules to a greater extent than aqueous extract that more pronouncedly stimulated rise in count of dendritic cells bearing costimulatory molecules (p 0.05). The activity of the examined proteins regarding their effect on CD83+ cells was comparable. Experimental protein-containing antigens derived from pneumococcal vaccine strain were shown to induce maturation of dendritic cells from bone marrow precursors, induce a decrease in the count of TLR2 and TLR4-expressing cells accounting for activating effect on innate immune effectors.

Relevance. Prevention of pneumococcal infection in the Russian Federation is carried out by imported polysaccharide and conjugated vaccines without taking into account the circulation of clinically significant isolates, which leads to the growth of previously rare genetic lines and serotypes that are not part of the vaccines, and does not protect against the carriage. Serotype-independent vaccines are being developed based on protective proteins and variants of whole-cell vaccines capable of providing a cross-protective effect against pneumococcus. Objective. Investigation of the protective properties of surface protein-containing antigens isolated from the immunogenic strain S. pneumoniae 6B No. 296 and their influence on key effectors of innate immunity. Materials and methods. S. pneumoniae 6B No. 296 was cultured in a semi-synthetic medium under stationary conditions at 5% CO2 for 5-7 hours. From inactivated bacterial cells, the experimental initial protein-containing preparation was obtained - an aqueous extract (A/E), from which a 30-100 kDa fraction (FR) isolated, and from the sterile culture supernatant, the protein-containing preparation - supernatant (S/N); in the preparations, the protein content was determined. Immunobiological properties were studied after double intraperitoneal immunization of BALB/c mice. The protective activity was determined after infection with virulent strains of S. pneumoniae serotypes 6B No. 1121 and No. 3. Phagocytic activity was studied by the number of granulocytes that absorbed heat-killed FITC-labeled S. aureus cells. The expression of Toll-like receptors (TLRs) and the subpopulation structure of mouse spleen lymphocytes were investigated after staining with FITC/PE-labeled monoclonal antibodies using flow cytometry. Statistical analysis of materials was carried out using parametric and non-parametric methods using the software package «Statistica for Windows», ver. 7.0 (Stat Soft, Inc). Results. The protective effect of FR upon infection with virulent strains of homologous (6B No. 1121) and heterologous serotypes (3 No. 3) was established; S/N protected mice when infected with strain 3 No. 3. All the studied drugs led to an increase in the number of phagocytic cells (the greatest effect was observed upon immunization with FR and S/N) and stimulated the expression of TLR2 and TLR4 positive cells (there was an increase in the number of TLR2-expressing cells during immunization with FR compared with A/E). When studying the immunophenotype of mouse lymphocytes, it was noted that the preparations induced the expression of effectors of innate and adaptive immunity. Conclusions. As a result of the studies, it was shown that the protective surface protein-containing fraction with MM 30-100 kDa is from tested experimental preparations the most active stimulator of innate and adaptive immunity, and requires further study to determine the possibility of using the serotype-independent pneumococcal vaccine in the development.

Relevance. Vaccines based on capsular polysaccharides of pneumococci are not active against serotypes that are not included in the vaccine, non-capsulated strains and do not protect against carriage caused by other serotypes. Their use leads to the replacement of dominant serotypes of pneumococci, the appearance of highly virulent strains, changes in the microbial landscape of mucous membranes due to the appearance of other etiologically significant pathogens of respiratory tract diseases. This requires the creation of intraspecific anti-pneumococcal immunity, which will be facilitated by the development of serotype-dependent drugs, which will include protein-containing antigens of pneumococci. Objective. Study of serotype-independent activity of protein-containing antigenic components obtained from freshly isolated and archival strains of S. pneumoniae. Materials and methods. Strains of three serotypes of S. pneumoniae were used: archival strains of serotypes 6B N296, 19F N 298 and 10A N297 and freshly isolated serotypes 6B N 1121, 19F N 1055 and serogroup 10 N 1193 (from the cerebrospinal fluid of patients with purulent meningitis).. In the experimental protein-containing preparations EPCP obtained, the protein content was determined. Protective activity of EPCP and virulence of strains were determined in the model of intraperitoneal immunization and infection of BALB/c mice; LD50 was calculated using the generally accepted modified Kerber formula. The immunophenotype of lymphocytes previously isolated from donor-mice whole blood was studied by flow cytometry. Statistical analysis of the materials was carried out using parametric and nonparametric methods using the application package «Statistica for Windows», ver. 7.0 (Stat Soft, Inc); in statistical analysis, the significance level of p was assumed to be < 0.05. Results and discussion. During cultivation there was the analysis of growth dynamics showed intensive accumulation of biomass of the archival strain N296 with low virulence, and lower - by virulent strain N 1121 isolated from the patient's cerebrospinal fluid. The protein content of drugs from serotype 6B strains did not differ. The strains of other serotypes isolated during the generalized infectious process were also more virulent than the archival strain. The effect on the immunophenotype of human lymphocytes of fractions of 50-100 kDa isolated from the initial preparations obtained by culturing serotype 6B, significantly increased only under the influence of the preparation from the archival strain. In the study of protective activity of the initial preparations from strains of serotype 6B and fractions with MM 50-100 kDa only triple immunization with the initial preparation from strain N 296, at a dose of 20 micrograms of protein per mouse, led to significantly greater survival of immunized mice from infection with the newly isolated virulent strain N 1121 of homologous serotype. A fraction of 30-100 kDa provided protection of mice twice immunized with 50 mkg of protein per mouse, with a high efficacy index of 8.9, even after infection with a freshly isolated strain of heterologous S. pneumoniae serotype 3 N 10196. Conclusion. The protein-containing fraction with MM 30-100 kDa obtained from a low virulent archival strain of S. pneumoniae serotype 6B N296 possessed protective activity against a newly isolated virulent strain of heterologous serotype after double immunization. Under the action of the studied protein-containing fractions, activation of the cellular component of immune system with the involvement of innate immunity effectors and T-lymphocytes is shown. These data can be considered as a evidence for further study of EPCP to assess the possibility of their use in the design of anti-pneumococcal drug with serotype-independent protective activity.

Relevance. Vaccines based on capsular polysaccharides of pneumococci are not active against serotypes that are not included in the vaccine, non-capsulated strains and do not protect against carriage caused by other serotypes. Their use leads to the replacement of dominant serotypes of pneumococci, the appearance of highly virulent strains, changes in the microbial landscape of mucous membranes due to the appearance of other etiologically significant pathogens of respiratory tract diseases. This requires the creation of intraspecific anti-pneumococcal immunity, which will be facilitated by the development of serotype-dependent drugs, which will include protein-containing antigens of pneumococci.Objective. Study of serotype-independent activity of protein-containing antigenic components obtained from freshly isolated and archival strains of S. pneumoniae.Materials and methods. Strains of three serotypes of S. pneumoniae were used: archival strains of serotypes 6B N296, 19F N 298 and 10A N297 and freshly isolated serotypes 6B N 1121, 19F N 1055 and serogroup 10 N 1193 (from the cerebrospinal fluid of patients with purulent meningitis).. In the experimental protein-containing preparations EPCP obtained, the protein content was determined. Protective activity of EPCP and virulence of strains were determined in the model of intraperitoneal immunization and infection of BALB/c mice; LD50 was calculated using the generally accepted modified Kerber formula. The immunophenotype of lymphocytes previously isolated from donor-mice whole blood was studied by flow cytometry. Statistical analysis of the materials was carried out using parametric and nonparametric methods using the application package «Statistica for Windows», ver. 7.0 (Stat Soft, Inc); in statistical analysis, the significance level of p was assumed to be < 0.05.Results and discussion. During cultivation there was the analysis of growth dynamics showed intensive accumulation of biomass of the archival strain N296 with low virulence, and lower - by virulent strain N 1121 isolated from the patient's cerebrospinal fluid. The protein content of drugs from serotype 6B strains did not differ. The strains of other serotypes isolated during the generalized infectious process were also more virulent than the archival strain. The effect on the immunophenotype of human lymphocytes of fractions of 50-100 kDa isolated from the initial preparations obtained by culturing serotype 6B, significantly increased only under the influence of the preparation from the archival strain. In the study of protective activity of the initial preparations from strains of serotype 6B and fractions with MM 50-100 kDa only triple immunization with the initial preparation from strain N 296, at a dose of 20 micrograms of protein per mouse, led to significantly greater survival of immunized mice from infection with the newly isolated virulent strain N 1121 of homologous serotype. A fraction of 30-100 kDa provided protection of mice twice immunized with 50 mkg of protein per mouse, with a high efficacy index of 8.9, even after infection with a freshly isolated strain of heterologous S. pneumoniae serotype 3 N 10196.Conclusion. The protein-containing fraction with MM 30-100 kDa obtained from a low virulent archival strain of S. pneumoniae serotype 6B N296 possessed protective activity against a newly isolated virulent strain of heterologous serotype after double immunization. Under the action of the studied protein-containing fractions, activation of the cellular component of immune system with the involvement of innate immunity effectors and T-lymphocytes is shown. These data can be considered as a evidence for further study of EPCP to assess the possibility of their use in the design of anti-pneumococcal drug with serotype-independent protective activity.

Aim. Comparative study of immunobiological properties of cell wall surface antigens and extracellular protein-containing antigens of Staphylococcus aureus. Materials and methods. Preparations: surface antigens of the cell wall (peptidoglycan, teichoic acids, protein antigens) of the strains of S. aureus containing in the staphylococcal vaccine «Staphylovac» (SV) and extracellular protein-containing antigens of S. aureus (EPCA). The parameters of innate immunity were evaluated by the effect of preparations on the immunophenotype of mononuclear leukocytes (ML) of the spleen of mice, expression of Toll-like receptors (using flow cytometry), phagocytic activity of macrophages of peritoneal exudate of mice after the introduction of SV and EPCA; the protective activity of preparations was studied in experiments of active protection of BALB/c mice. Results. To isolate EPCA, we used the virulent strain of S. aureus №6, and for obtaining surface antigens of the cell wall, 4 strains were selected, the most immunogenic of which was the low virulent strain of S. aureus №1991. Both preparations increased the number of TLR2 and MHC II expressing cells; CV administration caused an increase in the number of cells with CD25 marker, reflecting the early activation of immunocompetent cells, and EPCA immunization — led to a shorter expression of this marker. On the other hand, an increased number of CD19 positive cells were detected for a longer period of time during EPCA immunization. The longest activation of phagocytosis under the action of SV was established. High protective activity of bo-th types of the studied preparations was noted. Conclusion. The antigens of the cell wall and extracellular protein-containing experimental drugs possessed comparable immunological properties, however, the surface antigens to a greater extent activate innate immunity, and extracellular — adaptive immunity.