[Biological properties of the antigens isolated from Streptococcus pneumoniae serotype 3].

The protective activity of polysaccharide-containing antigens of Str. pneumoniae, serotype 3, was studied. The protective properties of the preparation were shown to be directly related to the quantitative content of carbohydrate substances, and the preparation was shown to be capable of inducing specific resistance. The study revealed that the resistance of mice to infection with the virulent strain of Str. pneumoniae, serotype 3, did not ensure the rapid elimination of the infective agent from the body. The antimicrobial effect of the preparation was due to the presence of protein, not subjected to deproteinization.