Protective properties and haemagglutinins in serum from humans and in serum from mice injected with a new polyvalent Pseudomonas vaccine.

Mice given single injections of a polyvalent pseudomonas vaccine produced anti-pseudomonas haemagglutinins against the 16 component immunogens of the multivalent vaccine. Mice passively immunized with sera from vaccinated mice were protected against lethal challenge by 8/10 strains of Ps. aeruginosa of homologous serotype. Protection by the serum was inversely proportional to the virulence of the challenge strains. Anti-pseudomonas haemagglutinins were always present in sera which passively protected mice against pseudomonas infection. Low levels of anti-pseudomonas haemagglutinins were present in some sera which failed to passively immunize mice against pseudomonas infection. Anti-pseudomonas haemagglutinins and antibodies involved in passive protection were mainly in the IgM fractions of mouse serum. Control human sera contained anti-pseudomonas haemagglutinins against most serotypes of Ps. aeruginosa. Sera from patients with burns contained high levels of anti-pseudomonas haemagglutinins against some but not all serotypes of Ps. aeruginosa. Sera from both controls and patients with burns passively protected mice against pseudomonas infection.