Uptake of IntSIIN. DC were incubated for 45 min with inhibitors (a) sodium azide/2-deoxyglucose (10, 1 mm), (b) cytochalasin D (10, 1 μg/ml), (c) amiloride (6, 0·6 μm), (d) filipin III (10, 1 μg/ml), (e) nystatin (50, 10 μg/ml) and (f) dextran sulphate (50, 10 μg/ml), followed by incubation with IntSIIN at 1 μg/ml and added to B3Z T cells for 24 hr. DC were pulsed with SIINFEKL in the presence of the biochemical inhibitor at the maximum dose and were added to B3Z T cells in parallel experiments to ensure no inhibitory effects on the presentation of SIINFEKL CTL epitope. LacZ activity in B3Z T cells was assayed by total culture lysates with LacZ substrate CPRG. The absorbance (560 nm) of culture wells was read after 4 hr incubation at 37°.