Various factors affect lipopolysaccharide sensitization in cell cultures

Commercially available lipopolysaccharide (LPS) is commonly used in research. Although protocols for its use are well established, we experienced a loss of LPS responsiveness in our cell cultures despite no obvious experimental changes. Our cell lines were stimulated with LPS and the media quantified for LPS responsiveness via an IL-8 ELISA. We discovered that the major cause of signal loss was differences in fetal bovine serum (FBS) formulation and concentration. One FBS formulation was notably better at eliciting an IL-8 signal than the second FBS, and 10% FBS in media was better at inducing LPS responsiveness than lower concentrations. We urge researchers to be aware of inherent variations in seemingly commonplace reagents as they may be unexpected sources of inconsistencies.