Figure 3.

Silica nanoparticles induce TNF-α production in dendritic cells. DC2.4 cells (A) and bone marrow-derived dendritic cells (B, D, and F) were exposed to silica nanoparticles (40 µg/ml) for 24 h. Then, bone marrow-derived cells were cultured with 10 ng/ml of GM-CSF, 10 ng/ml of IL-4, and 10 µg/ml of silica nanoparticles for 7 days (C, E, and G). Cells were harvested for RNA preparation. Transcriptional levels of cytokines were detected using RT-PCR (A~C). The supernatants of BMDCs were collected for 24 h. The levels of TNF-α (D and E) and IL-12p70 (F and G) in culture supernatants were determined by ELISA. Data represent the mean±SD of duplicates. ^*p<0.05, ^**p<0.01 for one-way ANOVA.