[An antigenic analysis and the protective properties of the R-form lipopolysaccharides of gram-negative bacteria].

The antigenic and immunogenic properties of the R-form lipopolysaccharides (R-LPS) of Pseudomonas aeruginosa, Salmonella minnesota, Escherichia coli and Shigella were studied. The results of the study revealed the existence of antigenic relationship between P.aeruginosa R-LPS and R-LPS Escherichia and Shigella. In serological tests no antigenic relationship between P. aeruginosa R-LPS and Salmonella R-LPS was revealed, but as shown in earlier experiments of the protection of mice, Re-glycolipid stimulated protective immunity against Pseudomonas infection in the animals. On the basis of R-LPS obtained from selected P. aeruginosa and Salmonella strains a vaccine was prepared which proved to be effective against infection caused by P. aeruginosa S-strain in experiments on mice. The vaccine induced protection in 40-100% of immunized mice, depending on the scheme of immunization. The vaccine may probably be effective against infections caused by other gram-negative bacteria.