Novel antigen system for tracking epithelial cell migration in serum-free culture.

We report here a unique system for tracking normal human urothelial cell migration in serum-free culture medium (HMRI-1). The key observation was that urothelial cells deposited red blood cell surface antigen on the culture dish in a remarkable pattern. Scrutiny of this pattern showed that each migrating cell left behind antigen imprints which formed parallel tracks the width of the cell. Hence the previous migratory history of the cells was instantly mapped by simply visualizing the antigen tracks deposited by the cells on the dish. Apart from providing a simple method for tracking urothelial cells, this observation has wider implications for mechanistic studies of epithelial cell movement in general. It also highlights the complicating effects associated with the addition of serum as a traditional culture supplement, since the inclusion of serum in the HMRI-1 medium abolished the above effect by inhibiting cell migration.