Effect of interaction between either monocytes or endothelial cells and K562 cells on secretion of IL-8 from endothelial cells. Monocytes (1 × 106 cells/mL) and human umbilical venous cells (VE cells, confluent) were cultured with or without K562 cells (5 × 104 cells/mL) for 2 days, and supernatants were then collected. (A) ELISA system for IL-8 was performed. Columns show the means of three independent experiments. Statistical analysis was performed using the Student’s t-test. (B) When VE cells were cocultured with (right) or without (left) K562 cells, the remaining VE cells, after removal of K562 cells, were collected and expression of intracytoplasmic IL-8 was examined as described in Materials and Methods. Purified mouse Ig G1 was used as a control antibody (CONTROL). The vertical axis indicates the frequency of fluorescence-positive cells. Intracytoplasmic IL-8 density is depicted on the horizontal axis. The representative data from three independent experiments are shown.
