Moderate Dose of Lipopolysaccharide Induces Tumor Necrosis Factor-alpha and Interleukin-6 Production by Human Monocyte-derived Macrophages

BACKGROUND: Macrophages have been widely used for in vitro studies. Despite different types and doses of stimulatory agents that have been tested, there is no consensus for the method. AIM: This study was aimed to determine a sufficient dose of lipopolysaccharide (LPS) to stimulate inflammatory response in macrophages. METHODS: Whole blood was collected from four donors after written informed consent. The monocytes were isolated from peripheral blood mononuclear cells and stimulated with macrophage colony-stimulating factor, LPS, and Interferon-gamma for 6 days until differentiated into macrophages. The production of Tumor necrosis factor-alpha (TNF-α) and Interleukin-6 (IL-6) were quantified after 24-h further stimulation with 100 ng/mL and 2 μg/mL of LPS. RESULTS: Both doses increased TNF-α _production compare to their controls, but not statistically different (p > 0.05). There were also no differences in IL-6 production between treatments, 56.55 ± 32.30 pg/mL and 70.96 ± 65.08 pg/mL, respectively. CONCLUSION: A dose of 100 ng/mL of LPS was sufficient to stimulate inflammatory response in human monocyte-derived macrophages. A 24-h duration of macrophage stimulation was sufficient to observed the production TNF-α.