Figure 2. Dose-dependent nitric oxide (NO) production (A) and TNF-α production (C) by HDM extract-stimulated MH-S cells.

MH-S cells were plated at 1x10⁶ cells/mL and challenged with increasing concentrations of HDM extract (0.1, 1 and 10 µg/mL) for 48h. Supernatants were collected and analyzed for NO and TNF-α production. (B) Effect of trypsin-treatment and protease inhibitors on the HDM induced NO production by MH-S cells. HDM extract (10µg/mL) was pre-treated with 5% (w/w) trypsin, 20µM E-64 or 100µM EDTA for 4 hours before addition to MH-S cells for 24 hours. Collected supernatants were assayed for NO production. All samples were analyzed in triplicate. Each bar represents the mean ± SEM from three replicate wells.