Detoxified bacterial endotoxins. I. Preparation and biological properties of an acetylated crude endotoxin from Salmonella typhimurium.

Martin, William J. (University of Utah, Salt Lake City), and Stanley Marcus. Detoxified bacterial endotoxins. I. Preparation and biological properties of an acetylated crude endotoxin from Salmonella typhimurium. J. Bacteriol. 91:1453-1459. 1966.-Acetylation of a crude endotoxin prepared by the Roschka-Edwards (RE) procedure from a strain of Salmonella typhimurium yields a product with reduced pyrogenicity in rabbits as well as one which is nontoxic in mice. A reduction in pyrogenicity of approximately 100 times was noted with this acetylated crude endotoxin when compared with the parent RE preparation. A comparison was made of immunogenicity with mice of Boivin, RE, and acetylated Roschka-Edwards (Acet-RE) preparations with a heat-killed, phenol-preserved (HP) vaccine prepared from the same strain of S. typhimurium. Less than pyrogenic doses of all vaccines were not protective. The least pyrogenic preparation (Acet-RE) was immunogenically effective in about five times the minimal pyrogenic dose. The data suggest that the Acet-RE preparation should be considered further in the search for enteric fever vaccines with lowered potential for undesirable systemic responses.