Figure 3.

Endotoxin contaminution dose not contribute to IL-1β induction by SAA/MSU. A. Synovial fibroblasts were pre-treated with SAA (1 μg/ml) or LPS (500 pg/ml) for 12 h. Cells were stimulated with MSU (200 μg/ml) for 24 h. Supernatants were analyzed for IL-1β production by ELISA. Values represent the mean ± SD of two independent experiments. P <0.01 compared to SAA-untreated synovial fibroblasts. B. Synovial fibroblasts were pre-treated with SAA (1 μg/ml) or LPS (500 pg/ml), which were exposed to 100°C (heat) in a water bath for 30 minutes, for 12 h. Cells were stimulated with MSU (200 μg/ml) for 24 h. Supernatants were analyzed for IL-1β production by ELISA. The endotoxin levels were also measured by limulus test using the same supernatants. Values represent the mean ± SD of two independent experiments.