Characterization of lipopolysaccharide-stimulated cytokine expression in macrophages and monocytes.

Objective: In vitro cell culture models are widely used in inflammation research; however, information regarding the time- and dose-dependency of inflammatory responses toward LPS in these cell lines is scattered in the literature.

Material: J774A.1 mouse macrophage and THP-1 human monocyte cell lines.

Treatment: J774A.1 and THP-1 cells were treated with 0-500 ng/mL lipopolysaccharide for 0-24 h.

Methods: SRB and BCA tests were used to measure total protein. Real-time PCR was used to determine gene expression levels, and ELISA was used to assess the protein levels. One-way ANOVA and Tukey's Honestly Significant Difference test were used to test the significance levels.

Results: In J774A.1 and THP-1 cells, cytokines responded in distinct patterns upon LPS stimulation in a time- and dose-dependent manner, and the differential regulation of the response to LPS between J774A.1 and THP-1 cells appeared to correlate with the differential regulation of TLR4 at the mRNA level.

Conclusion: In summary, this study indicated that temporal and dose-dependent responses to LPS need to be controlled for and that extrapolation of data on mechanisms may differ between cell lines of different origin.