Table 3.

Effect of plasminogen and PAI-1 on tunnel formation

	Total motile cells	Cylindrical tunnels	Helical tunnels
No addition	49 (15.4)	11 (3.4)	2 (0.6)
+ plasminogen (0.5 units/ml)	197 (71.9)	46 (16.8)	14 (5.1)
+ plasminogen (0.5 units/ml) + PAI-1 (0.5 μg/ml)	57 (20.9)	21 (7.7)	7 (2.6)

Human keratinocytes were plated on fibrin matrix and cultivated in serum-free medium in the absence of EGF. Plasminogen and PAI-1 were added to the medium at the indicated concentration. After 24 hours, cultures were fixed, and the number of tunnels was counted. Numbers in parentheses are percentage of adherent cells.