Recombinant Pneumolysin of Pneumococci Induces TLR4 Expression and Maturation of Dendritic Cells In Vitro.

Pneumolysin (Ply) is a target for the development of serotype-independent pneumococcal vaccines, an important condition for the efficacy of which is their ability to activate innate immunity with the subsequent formation of adaptive immunity. In this study, the ability of recombinant full-length Ply (rPly) of pneumococci to induce TLR expression and maturation of dendritic cells generated from mouse bone marrow was evaluated. It was shown that rPly in vitro increased the number of dendritic cells expressing Toll-like receptor 4 (TLR4) on the membrane. rPly caused maturation of dendritic cells generated from mouse bone marrow, which manifested in a decrease in the number of progenitor cells (CD34), an increase in the number of cells expressing the adhesion molecule CD38, costimulatory molecules CD80 and CD86, molecules of terminal differentiation of dendritic cells CD83, as well as molecules of antigenic presentation of the major histocompatibility complex class II.

[STUDY OF PROTECTIVE ACTIVITY OF PROTEIN-CONTAINING ANTIGENS OF STREPTOCOCCUS PNEUMONIAE IN A HETEROLOGOUS SYSTEM].

AIM: Study protective activity of protein-containing antigens of pneumococcus, obtained from serotypes 6B, 10A, 14, 19F, 23F and 36R, against infection with heterologous strains of S. pneumoniae. MATERIALS AND METHODS: S. pneumoniae strains of serotypes 3, 6B, 10A, 14, 19F, 23F and 36R, obtained from the collection of pneumococcus strains of Mechnikov RIVS, were used in the study. Protein-containing antigens of S. pneumoniae were isolated by acetone precipitations of supernatant fraction of culture medium. Protective activity of preparations of protein-containing antigens of pneumococcus as studied in experiments of active protection of BALb/c line mice. RESULTS: The data obtained give evidence, that protein-containing antigens of pneumococcus, isolated from serotypes 6B, 10A, 14, 19F and 23F, effectively protect animals from subsequent infection with a heterologous S. pneumoniae strain of serotype 3 No. 11/56. Protection was noted at a level from 80 to 100% (p ≤ 0.05). Similar protective effect was detected in another experiment in a group of mice, immunized with preparations of protein-containing antigens of pneumococcus, obtained from serotypes 6B and 36R, against infection with a heterologous S. pneumoniae strain of serotype 3 No. 11/56. Protection was noted at a level of 90% (p ≤ 0.05). CONCLUSION: The results of the experiments carried out allow to assume, that the main role in formation of cross-protection in experiments in animals is played by pneumococcus, proteins, that are a part of the studied preparations, and not polysaccharide antigens.