Effects of filipin on LFA-1. (A) EL4 cells and primary T cells were incubated with (+) or without (-) PMA in the presence of the indicated amount of filipin, and their adhesion to immobilized ICAM-1 in the presence (+) or absence (-) of blocking anti–LFA-1 antibody was assessed. Error bars indicate SD. (B) EL4 cells (left panel) and splenic T cells (right panel) were treated with (+) or without (-) 0.4 mg/mL or 0.1 mg/mL filipin, respectively, lysed with 0.05% Triton X-100, subjected to sucrose gradient centrifugation, and indicated molecules in the sucrose gradient were detected by Western blotting. The numbers indicate fractions starting from the low-density fraction.