PCN increases IL-8 release in PMA-differentiated U937 cells. (A) Different concentrations of PCN (5 μM, 25 μM, or 50 μM) were added to the cell cultures for 24 h. Supernatants were harvested for measuring IL-8 secretion by ELISA. (B) A fixed concentration of PCN (50 μM) was added to the cell cultures for 8, 16 or 24 h. Supernatants were harvested for measuring IL-8 level by ELISA. Values represented are the mean ± SD of four independent experiments in triplicate. **p < 0.01 compared with PMA-differentiated U937 cells. PMA: phorbol 12-myristate 13-acetate.
Chai et al. BMC Microbiology 2014 14:26 doi:10.1186/1471-2180-14-26