Expression of Lu/BCAM proteins, integrin α₄β₁, and VCAM-1 in HUVECs. (A) HUVECs and A498 cell-surface proteins were biotinylated, and Lu/BCAM proteins were immunoprecipitated after cell lysis using anti-Lu mAb F241. Immunoprecipitates were run on 8% polyacrylamide gel, and the proteins were revealed using streptavidin–biotinylated HRP. (B) Flow cytometry analysis of Lu/BCAM, integrin α₄, and VCAM-1 expression in HUVECs. VCAM-1 expression was tested in HUVECs before and after stimulation by TNF-α. Solid lines represent cells positive for each protein; dashed lines, cells incubated with isotype-matched control antibodies.