Infection protective property of the common antigen (OEP) of Pseudomonas aeruginosa and its chemical composition.

The protein moiety (OEP) of the endotoxin of Pseudomonas aeruginosa is a proteinaceous compound composed of possessing 77% protein and a small amount of lipid and sugar. The antigen has been proved to possess a common protective property against P. aeruginosa infections regardless of serotype and also to possess an antigen common to all the serotype strains of P. aeruginosa. When OEP was subjected to protease digestion, (protease-treated OEP) the protein content was reduced to 17% without a change in the lipid and sugar composition. The protease-treated OEP was no longer found to possess a serologically common antigen and was also found to have lost the common protective property against infections due to all the serotypes of P. aeruginosa. In conclusion, a serologically common antigen (OEP) as well as a common infection protective property was found to reside in a protein portion of the antigen.