OPN mediates maturation from immature DCs to mature DCs OPN mediates maturation from immature DCs to mature DCs. To induce DC maturation, immature DCs were incubated with LPS (1 μg/ml) for another 48 h with or without anti-OPN Ab (1, 3, or 5 μg/ml). OPN mediates maturation from immature DCs to mature DCs. To induce DC maturation, immature DCs were incubated with LPS (1 μg/ml) for another 48 h with or without anti-OPN Ab (1, 3, or 5 μg/ml). (a) Control mature DCs (mDCs) obtained by stimulation with LPS (1 μg/ml) acquired the morphology characteristic of DCs. (b) Maturing DCs treated with anti-OPN (1 μg/ml) Ab also showed dendritic morphology. However, the majority of cells remained in the immature state as judged by morphology. (c) Changes in surface expression of HLA-DR (MHCii), CD83, and CD86 on DCs after maturation. Mature DCs expressed high levels of MHC class II and CD86, whereas maturing DCs treated with anti-OPN Ab expressed lower levels of HLA-DR and CD86, whereas the inhibitory effect of anti-OPN Ab on DC maturation was dose dependent. Results are representative of three independent experiments. Kodai Kawamura et al. Clin. Diagn. Lab. Immunol. 2005; doi:10.1128/CDLI.12.1.206-212.2005