Loading cells with anti-ICAM nanocarriers does not affect endocytosis and trafficking of dextran. (A) Internalization of a fluid phase marker, fluorescent Texas Red dextran, by either control HUVECs or cells treated with pharmacological inhibitors of internalization by clathrin-coated pits (MDC), caveoli (Filipin = Fil), or macropinocytosis (Amiloride = Amil). Note that TR dextran enters cells via diverse endocytic pathways. (B) HUVECs, either control or preloaded with a saturating dose anti-ICAM/NCs, were incubated with TR dextran and traffic to lysosomes was tested. Yellow color (arrowhead): colocalization of TR dextran with lysosomes labeled in green by FITC–anti–LAMP-1 (control cells) or FITC–anti-ICAM/NCs (particle-loaded cells). Bar = 10 μm. (C) The number of TR dextran-labeled endocytic vesicles per cell and (D) percent of these localizing to lysosomal compartments was determined by fluorescence microscopy. Data are M ± SEM from n > 10 cells.