Time sequence of PECAM-1 movement on cultured HUVECs during PMN transmigration.

A PMN was transmigrating through a monolayer of living HUVEC specimen that was previously immunostained with anti–PECAM-1 antibody and Alexa Fluor–conjugated secondary antibody. Symbols indicate the momentary moving directions of 2 adjacent PECAM-1 clusters (B-E). This PMN transmigration process was completed in about 80 seconds, and the resealed bicellular boundary was restored almost to its original state (compare panels A and F).