Migration of monocytic THP-1 cells and CD14⁺monocytes.

MCP-1 effect on transwell migration of monocytic THP-1 cells (A) and CD14⁺ monocytes (B). After a 3-hour incubation at 37°C with 5% CO₂, cells that migrated from the upper to lower compartments were collected. The percentage migration was derived from counting cells with the trypan blue dye exclusion method (closed bars). To remove concentration gradient, the cells were incubated for 1 hour at room temperature with the indicated concentrations of MCP-1 before loading onto inserts (open bars).