VEGF suppressed the differentiation of immature DCs into mature DCs. Immature DCs were cultured alone or with Tca8113 cells in medium containing GM-CSF, IL-4 and TNF-α for 48 h. (A) The expression of HLA-DR, CD40, CD80, CD83 and CD1a were analyzed by flow cytometry. (B) The expression of HLA-DR, CD40, CD80, CD83 and CD1a decreased when immature DCs were co-cultured with Tca8113 cells for 48 h. (C) The expression of HLA-DR, CD40, CD80, CD83 and CD1a was suppressed in DCs when co-cultured with Tca8113 cells. (D) The expression of HLA-DR, CD40, CD80, CD83 and CD1a increased when immature DCs were co-cultured with VEGFsiRNA-V2-treated Tca8113 cells for 48 h. (E) The expression of HLA-DR, CD40, CD80, CD83 and CD1a was higher on immature DCs when co-cultured with VEGF siRNA-V2-treated Tca8113 cells than with wild-type Tca8113 cells. Data are the mean ± SD of triplicate samples. *P<0.05 versus control. DCs, dendritic cells; VEGF, vascular endothelial growth factor; siRNA, small interfering RNA; GM-CSF, granulocyte macrophage colony-stimulating factor; IL-4, interleukin-4; TNF-α, tumor necrosis factor α.