Prevention of fatal experimental burn-wound sepsis due to Klebsiella pneumoniae KP1-O by immunization with homologous capsular polysaccharide.

The immunogenicity and protective capacity of highly purified Klebsiella pneumoniae KP1-O capsular polysaccharide was evaluated. Polysaccharide antigen from K. pneumoniae KP1-O was isolated, purified, and characterized. The final preparation consisted primarily of carbohydrate and was of high molecular weight (greater than or equal to 5 X 10(6]. The polysaccharide antigen was found to be immunogenic in mice in a dose-dependent fashion, as determined by ELISA. Prior immunization of mice with low doses of K. pneumoniae KP1-O polysaccharide provided highly significant protection (P less than .01) against fatal burn wound sepsis with the homologous strain. The level of protection correlated with IgG ELISA titers and was dependent upon prevention of bacteremia following challenge.