Evaluation of Cross Protection Conferred by Human Antisera against Septic Shock Caused by Endotoxins

ObjectivesTo evaluate the cross protection conferred by pooled anti-lipopolysaccharide antibodies in human sera against a challenge with a specific lipopolysaccharide (LPS) endotoxin.MethodsThree groups, each comprising of fifteen weight and sex matched Tuck-ordinary (T.O) mice were passively immunized intraperitoneally with 0.25 ml of 0.15M sterile PBS saline, 0.25 ml of high titer J5 (mutant E.coli 0111:B4) LPS antiserum, and 0.25 ml of high titer concoction LPS antiserum containing a mixture of antibodies against four different endotoxins. After one hour all mice received intraperitoneal injection of 5 μg (LD-100) LPS from Salmonella abortus equii in sterile PBS containing 10 mg D-galactosamine. Survival of mice was assessed at four hourly intervals for 24 hours. Mice surviving 24 hours after administration of LPS were considered as protected.ConclusionConcoction LPS antiserum was able to provide 100% protection since all the mice in that group survived at the end of 24 hours. E.coli J5-LPS antiserum could protect only nine out of fifteen mice (60%), whereas none of the mice survived in the group that received normal saline (p< 0.0001, χ2 =30.53).