E. coli Lipopolysaccharide: acute oral toxicity study in mice.

A single dose of endotoxin (lipopolysaccharide) from a common laboratory cloning and expression strain (Escherichia coli BL21[DE3]) was administered to groups of male and female CD-1 mice (n=5/group) at doses up to 1,000,000 endotoxin units (EU) per mouse by oral gavage. The mice were observed for mortality, body weight effects, and clinical signs for 14 days after which they were sacrificed for gross organ necropsy. All mice survived until the scheduled sacrifice, no clinical signs of toxicity were observed, no test substance-related body weight losses occurred and no gross lesions were present at necropsy. Under the conditions of this study, oral administration of E. coli BL21(DE3) endotoxin to mice at a dose of up to 1,000,000 EU/mouse produced no evidence of toxicity.