One of two kinds of inhibitors, cytochalasin B and DMA, which inhibit APC phagocytosis and pinocytosis of antigens, respectively, was added to the culture of macrophages 1 hr prior to the addition of Alexa 488 -OVA-or DQ-OVA-coupled oleoyl liposomes. One hour later, flow cytometric analysis was performed. As shown in Fig. 3 , the effect of cytochalasin B on the antigen uptake and digestion of liposome-coupled OVA by APCs was limited. On the other hand, DMA significantly reduced both antigen uptake and digestion of antigens by macrophages.