Difference in clearance of exogenously administered smooth-form LPS following host responses among normal,sensitized and LPS-tolerant mice

Abstract

Clearance of exogenously administered Salmonella abortus equi LPS from the circulation following induction of host responses, e.g. release of soluble CD14 (sCD14) and TNFα production, were investigated. The endotoxin unit of administered LPS in plasma was monitored by a combined method. After 1 h, more than 80% of injected LPS disappeared from the circulation of normal mice at all doses except a 100 μg dose, but sCD14 in plasma could not yet be detected by Western blotting. Release of sCD14 reached a peak 9 h after LPS injection. According to pretreatment with either Propionibacterium acnes or silver nitrate, the clearance rates of exogenously added LPS from the circulation were accelerated in comparison with the rate in normal mice, but plasma TNF levels were the opposite. In LPS-tolerant mice, LPS clearance and production of TNF and sCD14 was reduced. Pretreatment with anti-CD14 mAb reduced LPS-induced TNF production but did not influence the clearance rates. Taken together, in vivo, sCD14 may not play a critical role for early LPS clearance.