C-polysaccharide in a pneumococcal vaccine.

The 14-valent pneumococcal vaccine, Pneumovax, was found to contain approximately 25o micrograms per ml of the cell-wall antigen, C-polysaccharide (C-Ps), in addition to 100 micrograms per ml of each of the 14 capsular polysaccharides. Rabbit anti-C-Ps antiserum recognized four components of this C-Ps with different antigenic determinants, corresponding to four fragments with different molecular sizes. By lectin affinity chromatography it was demonstrated that some of the C-Ps in the vaccine contained cell-wall residues. The methods used in this study can also be used for the characterization of other polysaccharide preparations.