HUVECs adherent to various substrata examined by light microscopy. For the adhesion assay, refer to the legend for Fig 4A. Whenever inhibitors were used, HUVECs were preincubated with either LJIb1 or echicetin for 15 minutes on ice before being applied, together with the inhibitors, onto the precoated plate. This figure shows the morphology of HUVECs adherent to different ligands observed under light microscopy. HUVECs adherent to vWF (A), alboaggregin A (B), and alboaggregin B (D) showed extensive cell spreading, whereas cells attached to echicetin (C) showed cell clumping without prominent cell spreading. The presence of 50 μg/mL LJIb1 (E) or 500 nmol/L echicetin (F) demonstrated inhibition of cell adhesion and cell spreading on alboaggregin B.