In vitro cytotoxicity of lipopolysaccharides for chinese hamster ovary cells

From our survey of various lipopolysaccharide (LPS) preparations, we demonstrated that three out of five commercial LPS preparations of Salmonella typhimurium were not cytotoxic for Chinese hamster ovary (CHO) cell monolayers at a concentration of 1000 μg/ml. One commercial LPS preparation produced cellular damage at a concentration of 1000 μg/ml and another at 400 μg/ml. Two S. typhimurium LPS preparations made in our laboratory were also cytotoxic at a concentration of 1000 μg/ml but not at lower concentrations. Cell-free sonic lysates of S. typhimurium TML R66 were cytotoxic when tested undiluted and up to a dilution of 1:20. Based on the 2-Keto-3-deoxyoctonate (KDO) content of all preparations, sonic lysateas were cytotoxic at KDO concentrations of 0.42 μg/ml while the KDO content of the most cytotoxic LPS preparation was 15.2 μg/ml. There was no apparent correlations between KDO content of the LPS preparations and cell detachment, leading to the conclusion that cell detachment activity of Salmonella cell lysates cannot be attributed to their LPS content.