Properties of US Standard Endotoxin (EC-5) in human male volunteers

Abstract

There has been a great interest in endotoxin testing using both Limulus amebocyte lysate (LAL) and the rabbit pyrogen test. It is often difficult to relate the results to the actual biological potency of endotoxin in man. There is a need to have the US Standard Endotoxin (Lot EC-5) tested in human volunteers so that rabbit and human data can be compared.

Human male volunteers were divided randomly into 5 groups of 12. Each group was given an intravenous injection of Lot EC-5 at a level of either 0, 2, 4, 8, or 16 endotoxin units (EU) per kg of body weight. The oral temperature was taken and recorded every 15 min for 8 h. The pyrogenic properties of the US Standard Endotoxin in humans over the test period were determined. The results indicated that there is a direct correlation between EU/kg administered and temperature rise. The threshold pyrogenic dose (≥ 1.0°F rise in 50% of volunteers) in this study is approximately 4.1 EU/kg.

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