[Chemical and immunogenic properties of the capsular antigen of Staphylococcus aureus. III. Protective activity of capsular antigen in experiments on mice].

Experiments were conducted on 1500 albino mice; protective activity of 7 batches of S. aureus capsular antigen isolated from 5 strains was studied. The animals were immunized subcutaneously with different doses of the preparation (from 0.001 to 10000 microgram) once, twice, and thrice, and infected intraperitoneally with 6 encapsulated cultures. Capsular antigen proved to possess weak protective properties. The following regularities were revealed: 1) high antigen doses (over 5 microgram) increased mouse sensitivity to staphylococcus infection; 2) the greatest protective activity was shown by doses within 0.01-1 microgram; 3) there was no distinct "dose-effect" dependence; 4) single immunization was less effective than double and triple; 5) antigenic specificity of the capsular material was not connected with its protective properties.