CHARACTERIZATION OF A CR51-LABELED ENDOTOXIN AND ITS IDENTIFICATION IN PLASMA AND URINE AFTER PARENTERAL ADMINISTRATION

Abstract

The incubation of endotoxin with Na₂Cr⁵¹O₄ yielded a product which was well labeled. That the label was fixed on the endotoxin itself was shown by autoradiography on specific lines of precipitation formed in agar. Ultracentrifugation at 40,000 RPM sedimented 80 per cent of the total weight of the starting Boivin preparation. Agar diffusion patterns with subsequent autoradiographs demonstrated that the chromium tag was associated only with the heavy fractions of the pellet. The supernatant contained precipitable, but unlabeled endotoxin. Toxicity measurements showed that more than 99 per cent of the total toxicity resided in the pellet fractions.