Decelerated intracellular traffic of second dose of anti-ICAM nanocarriers. Cells prelabeled with Texas Red dextran were incubated with FITC-labeled anti-ICAM/NCs (A) or nonlabeled anti-ICAM/NCs (B) for 1 hour at 4°C, warmed to 37°C after washing of nonbound materials, incubated for indicated time at 37°C, and counterstained with secondary labeled antibodies, which would stain surface-bound nanocarriers in blue. The first dose was followed by the same dose of FITC-labeled anti-ICAM/NCs at the indicated time (B). The absence of blue staining in panels A and B indicates that both first and second doses are internalized. Yellow color shows colocalization (arrowhead) of anti-ICAM/NCs with red-labeled lysosomes. Bar = 10 μm. (C) Anti-ICAM/NC colocalization with lysosomes is plotted as a function of time after internalization of the corresponding dose. Data are M ± SEM for n > 10 cells from 2 independent experiments. (D) Schema of recurrent intracellular traffic and deceleration of lysosomal delivery of the second dose of anti-ICAM/NCs.