An attempt to localize the vaccinating power of Klebsiella pneumoniae ribosomal preparations using saccharose-gradient ultracentrifugation.

The study of the vaccinating power of ribosomal vaccines against Klebsiella pneumoniae led us to define the chemical nature which supports this protective activity. We tried to separate this support and the ribosomes by sucrose gradient ultracentrifugation. We isolated high protective membrane vesicles by this technique applied to salt-washed ribosomal preparations. When the ribosomal preparations were exposed to SDS, the protective activity was conserved all along the gradient, with no correlation with the ribosome concentration. The addition of bovine serum albumin to the ribosomal preparation focused the protective activity on the ribosomal peak. No correlation was observed between the response to capsular polysaccharide and the vaccinating power of the fractions.