Extracellular S100A9 protein stimulates pro-inflammatory response in macrophages.

<p>Human U937 macrophages were incubated with purified recombinant human S100A9 protein (10 µg/ml) for 6 h and 12 h. The medium supernatant was collected to assess levels of human TNF-α (TNF) (<b>A</b>) and human IL-6 (<b>B</b>) by ELISA. Mouse J774A.1 macrophages were incubated with purified recombinant mouse S100A9 protein (5 µg/ml) for 6 h and 12 h. The medium supernatant was collected to assess levels of mouse TNF (<b>C</b>) and mouse IL-6 (<b>D</b>) by ELISA. The values represent the mean ± standard deviation from three independent experiments performed in triplicate. *p<0.05 using a Student's t test. Vehicle control cells (veh) were incubated with HBSS buffer.