MDMs (1×103cells/well) were pretreated for 30 min at 37°C with Iscove’s modified Dulbecco’s medium (IMDM) alone, 25 μg/ml of anti-CD63 antibody (Invitrogen), 25 μg/ml of anti-CD82 antibody (Invitrogen), or 25 μg/ml of anti-CD4 antibody (BD Sciences) as a positive inhibition control. Thereafter, HIV-1 SX (m.o.i.= 0.02) was added, and incubated for 1 h at 4°C, and unbound virions were removed by washing with cold PBS containing 1% FBS. The cells were trypsinized, and the amount of cell-associated p24 in trypsin was determined with p24 Capture ELISA kit. Controls included cells treated with trypsin only and untreated (no Ab) cells. Experiments were performed in triplicate. **P<0.01, compared with anti-CD82 group.