Immunologic Paralysis Produced in Mice by Klebsiella Pneumoniae Type 2 Polysaccharide

This is the authors' abstract. We don't add key points for this paper.

Summary Mice injected with varying amounts of Klebsiella pneumoniae type 2 polysaccharide were subsequently challenged with living homologous organisms after varying intervals of time. Of three preparations of polysaccharide, one was essentially nontoxic and nonimmunizing; the other two were approximately equal in antigenicity. In the groups of animals receiving 2.5 µg of these latter preparations, there was a greater proportion of survivors than in groups given 750 µg. Passively protective antibodies were detected within 5 days in the serum of mice given 2.5 µg, whereas in the serum of animals given 750 µg of polysaccharide such antibodies were not evident before 60 days—a time when the degree of active protection in comparable animals was waning.