Internalization of gp120 by MDDCs.

Cells were preincubated with anti-CD4 (Leu3a) to detect CLR-bound gp120 and with mannan to detect CD4-bound gp120 or binding media for total external or internal gp120 for 30 minutes at 4°C. Cells were then incubated with 5 μg/mL b-gp120 for 30 minutes at 4°C, washed twice in binding media, and incubated in culture media for the indicated times and stained to detect extracellular or intracellular gp120 as outlined in “Materials and methods.”