Figure 3.

Effect of sweet potato PAP on PA FLA-induced IL-8 secretion in A549 cells. A549 cells were initially seeded onto 96-well plates at a density of 1.5×10⁴ cells per well and cultured to 80% confluency at 37°C in a 5% CO₂ incubator. Various concentrations of FLA (0, 0.1, 1, 10, 100, 1,000 ng/mL) were treated with 1 μL of sweet potato PAP (11.6 μg) for 6 h. Then, enzyme-treated FLA and intact FLA at each concentration were applied to the cells for 12 h. The level of IL-8 was assayed at OD 450 nm using Cymax Human IL-8 ELISA kit. The data were expressed as the mean and standard errors from three experiments. PAP, purple acid phosphatase; PA FLA, Pseudomonas aeruginosa flagellin; IL-8, interleukin-8; OD, optical density; ELISA, enzyme-linked immunosorbent assay. ^a–d Means lacking common letters differ significantly (p<0.05).