Reaction of Endotoxin and Surfactants

Dissociation of Salmonella enteritidis endotoxin into nonpyrogenic subunits of low molecular weight with sodium deoxycholate resulted in reduction of its antigenic and adjuvant properties. Removal of the surfactant by dialysis, permitting reaggregation of the subunits into larger pyrogenic particles, restored antigenic activity. Quantitative precipitation curves confirmed that the molecular species of endotoxin formed after removal of the sodium deoxycholate were much smaller than the original, in the case of phenol-extracted endotoxins, and the same as the original with aqueous ether-extracted endotoxins.