FIG. 3.

Enhanced HIV endocytosis and distinct viral trafficking in mDCs relative to iDCs. DCs were exposed to AT-2-inactivated R5 HIV for 1.5 h, washed thoroughly, fixed, and prepared for electron microscopy. (A, B, and C) Cell surface-bound HIV and internalized viral particles in iDCs. (D, E, and F) HIV internalization is significantly enhanced in mDCs. Arrows indicate DC surface-associated HIV particles or intracellular compartments that trapped intact HIV particles. (G, H, and I) RR labeling of mDC plasma membranes. (I) Higher-magnification image of panel H (a partial area). The open arrows indicate RR-labeled mDC plasma membranes, and the black arrows point to HIV-containing compartments and HIV particles that were not labeled with RR. Scale bars, 0.1 μm (A to F), 0.2 μm (G, I), and 0.5 μm (H).