FIG 4.

Fh12 reduces production of nitric oxide from macrophages. Monocyte-derived macrophages (MDM) from naive donors were isolated and cultured in triplicate in 96-well plates (10⁶ cells/well) at 37°C with 5% CO₂. Cells were stimulated with LPS (15 μg/ml) or Fh12 (5 μg/ml) prior to or after LPS stimulation for 48 h, after which the supernatants were removed and centrifuged at 1,000 × g. Levels of nitric oxide (NO) measured in the cell supernatant were found to be significantly diminished in cells treated with Fh12. Adherent cells (MDM) were removed with a scraper and analyzed for intracellular arginase activity by a colorimetric method. The arginase activity was found to be significantly increased in cells that were treated with Fh12 prior to or after LPS stimulation. Results represent the means ± SD from a minimum of three experiments, each in triplicate. **, P < 0.005 compared with the PBS control group.