Osmotic shock fluids from salmonella R-mutants. Chemical composition and protective capacity against S. typhimurium infection in mice.

Salmonella R-mutants of different chemotype were subjected to osmotic shock treatment according to the method of Willis et al. (18). Chemical composition (protein, LPS, palmitic acid and nucleic acids) as well as the polypeptide patterns of the shock fluid and hypertonic fluid (in which the cells were suspended before shock treatment) were determined and compared with material extracted by urea treatment carried out to get protein from the cell surface. The results indicate that even components from the cell surface have been released by shock treatment. All the extracts mentioned above showed protective activity in mouse against infection.