PROTECTION AGAINST FATAL PSEUDOMONAS-AERUGINOSA BURN WOUND SEPSIS BY IMMUNIZATION WITH LIPOPOLYSACCHARIDE AND HIGH-MOLECULAR-WEIGHT POLYSACCHARIDE

A murine burn wound model was employed to evaluate the relative efficacy of purified P. aeruginosa lipopolysaccharide (LPS) and high-MW polysaccharide as protective immunogens. LPS was highly immunogenic and protective; three 0.001 .mu.g doses elicited good IgM and IgG titers and increased the mean lethal dose > 1000-fold. The level of protection against a live challenge correlated with antibody titers and was serotype specific. An immunizing regimen which evoked only an IgM response still offered substantial protection. Immunization with a high-MW polysaccharide was also protective; .apprx. 1000-fold more high-MW polysaccharide, as compared with LPS, was needed to protect mice to an equivalent degree. Immunization with LPS promoted bacterial clearance and prevented establishment of bacteremia. A multivalent LPS vaccine conferred high levels of protection (110- to 53,000-fold) against 8 different challenge strains of various serotypes.