The effect of conditioned media on cytokine release from cells. IL-1β, IL-6, IL-8 and TNFα supernatant levels were measured 24 hours after mesothelial cells were exposed to media from CNT-treated macrophages. A length-dependent increase in concentration was observed for each of the cytokines. The black horizontal lines on the graph indicate the level of cytokine expressed by the THP-1 cells which is still present in the conditioned media. Data expressed as mean ± sem, n = 3. Significance versus vehicle control *** indicates p < 0.001.