[Effect of strain-producer and cultivation medium on cross antigenic activity of Streptococcus pneumoniae water soluble antigens].

ABSTRACT

AIM: Production of water soluble protein-containing antigens from various strains of S. pneumoniae during cultivation in complete and semi-synthetic culture media as well as selection of strains with cross antigenic activity. MATERIALS AND METHODS: S. pneumoniae 3, 6A, 6B, 14, 10A, 18A, 19A, 19F, 23F serotype strains were cultivated in brain-heart broth and semi-synthetic medium with addition of aminopeptide for 24 hours at 37 degrees C for the production of water soluble antigens. The antigens were obtained by a method of triple water extraction from acetone dried microbial cells. Chemical composition of preparations, electrophoresis mobility of protein-containing components of preparations and cross antigenic activity in gel immune diffusion reaction by using rabbit hyperimmune sera were studied. RESULTS: In studies of 10 pneumococcus strains from various serotypes a method of microbial cell inactivation by acetone was selected that allows to produce preparations with high protein content (25.5 - 53.1%). Electrophoretic separation of the preparations revealed difference in the preparations obtained from various pneumococcus strains in the layout of major protein lines in the 8 - 95 kDa range. The most virulent and immunogenic S. pneumoniae strain that during cultivation in semi-synthetic medium was characterized by intraspecies cross antigenic activity and in gel immune diffusion reacted with all the studied sera against 3, 14, 18C, 23F serotype strains was selected. CONCLUSION: The study resulted in the selection of a technologically simple method of production of pneumococcus antigens with high protein content and showed that only 1 of the studied preparations produced from a virulent strain with poorly expressed S. pneumoniae capsule during cultivation in semi-synthetic medium has the highest cross antigenic activity.