DIFFERENCE IN CLEARANCE OF EXOGENOUSLY ADMINISTERED SMOOTH-FORM LPS FOLLOWING HOST RESPONSES AMONG NORMAL, SENSITIZED AND LPS-TOLERANT MICE

Clearance of exogenously administered Salmonella abortus equi LPS from the circulation following induction of host responses, e.g. release o f soluble CD14 (sCD14) and TNF alpha production, were investigated. Th e endotoxin unit of administered LPS in plasma was monitored by a comb ined method. After 1 h, more than 80% of injected LPS disappeared from the circulation of normal mice at all doses except a 100 mu g dose, b ut sCD14 in plasma could not yet be detected by Western blotting. Rele ase of sCD14 reached a peak 9 h after LPS injection. According to pret reatment with either Propionibacterium acnes or silver nitrate, the cl earance rates of exogenously added LPS from the circulation were accel erated in comparison with the rate in normal mice, but plasma TNF leve ls were the opposite. In LPS-tolerant mice, LPS clearance and producti on of TNF and sCD14 was reduced. Pretreatment with anti-CD14 mAb reduc ed LPS-induced TNF production but did not influence the clearance rate s. Taken together, in vivo, sCD14 may not play a critical role for ear ly LPS clearance.