Transendothelial migration of monocytes in rat aorta: distribution of F-actin, alpha-catnin, LFA-1, and PECAM-1.

To determine changes in the distribution of cell adhesion molecules during diapedesis of monocytes in situ, we labeled aortic whole mounts from hypercholesterolemic rats with Texas red-phalloidin and antibodies to LFA-1, PECAM-1, or alpha-catenin, and analyzed them by laser scanning confocal microscopy. Monocytes transmigrated through circular openings (transmigration passages) formed by pseudopodia that penetrated between adjacent endothelial cells. Transmigrating monocytes remained spherical above the endothelium, while spreading beneath it.