[Study of cross-activity of Streptococcus pneumoniae antigen preparations]

Study cross-activity of S. pneumoniae antigen preparations.

Antigen preparations were obtained by ultrasound disintegration (from bacteria in R-form), extraction with water (from serotype 3 bacteria), cetavlon and trichloroacetic acid (from serotype 6A bacteria). Chemical composition and immunochemic properties of preparations were studied by contemporary methods as well as in experiments with direct and cross-protection of mice from infection.

3 of 4 preparations (except ultrasound disintegrate) had approximately 30% of protein. In immunodiffusion reaction they interacted with hyper immune rabbit sera obtained against 12 various pneumococcus serotypes--1, 3, 4, 6A, 6B, 9V, 9N, 14, 18C, 19A, 19F and 23F. In animal experiments 30 - 70% of mice were protected from subsequent infection with knowingly high dose of homologous and 3 heterologous pneumococcus strains. In immunoblotting the highest number of components serologically active with heterologous sera was formed by cetavlon extract (12 - 23). Addition of capsule polysaccharides to the preparation increased its cross-protective activity.

By data set and the highest yield, water extract is reasonable for isolation of cross-reactive proteins of pneumococcus. Development of another method of extraction from cultural fluid is necessary for obtaining extracellular protein antigens. Generation of vaccines containing cross-reactive proteins of pneumococcus and capsule polysaccharides is a promising direction.