Type-specific vs. cross-protective vaccination for gram-negative bacterial pneumonia.

Groups of guinea pigs received four injections intramuscularly of lipopolysaccharide vaccine derived from Pseudomonas aeruginosa, cross-protective core glycolipid vaccine derived from the J-5 mutant of Escherichia coli O111, or saline during a two-week period. Titers of passive hemagglutinating antibody to vaccine antigens in serum routinely increased fourfold or more. Experimental hemorrhagic pseudomonas pneumonia was then induced, from which the rates of survival were 15% among animals receiving saline, 81% among animals receiving pseudomonas vaccine (P less than 0.001), and 42% among animals receiving J-5 vaccine. Thus, only weak cross-protection against pseudomonas pneumonia was detected in the recipients of J-5 vaccine. Further studies revealed no protection against pneumonia due to either E. coli or Klebsiella in animals receiving J-5 vaccine. From these data, species-specific vaccination appears to be superior to vaccination with cross-protective antigen against experimental pseudomonas pneumonia.