Restoration of Endotoxin Activity following Alteration by Plasma

ENDOTOXINS from Gram-negative bacteria, when added to human plasma or certain fractions of human plasma and incubated at 37° C for several hours, show reduced immunological reactivity, pyrogenicity, and toxicity 1 . Physical changes occur in such altered endotoxins, as manifested by a more rapid diffusion rate 2,3 and a lowered ability to be sedimented in a high-speed centrifuge 2,4 when compared with native endotoxin. The kinetics of the inactivation of endotoxin by plasma or its fractions suggested that the endotoxin was being degraded by a plasma enzyme. However, germane to the proof of such a tenet should be the isolation and identification of products which have come from a previously undergraded endotoxin. Examination of the literature revealed a paucity of such data.