Reaction of Escherichia coli Endotoxin with Lithium Aluminum Hydride

Summary

Treatment of Boivin-type endotoxin from E. coli with LiAlH₄ according to the method of Noll and Braude yielded a small amount (about 10%) of an essentially pure nonphosphorylated polysaccharide which was nontoxic and nonpyrogenic. In contrast to their RE fraction this product did not stimulate the production of antibodies in rabbits, precipitate antibody nor produce tolerance to endotoxin. The bulk of the product resulting from treatment with LiAlH₄ consisted of biologically unaltered endotoxin. It was isolated as a rapidly soluble, lipid-containing aluminum citrate-endotoxin complex, the infrared spectrum of which was nearly identical to that of an RE fraction with 100-fold reduced pyrogenicity. No correlation was found between fatty acid ester content, as estimated from infrared spectra, and toxic and pyrogenic properties of the endotoxin.