Role of DC-SIGN and CD4 on HIV-1 exogenous presentation by DCs. Primary immature DCs from 8 different HLA-A2⁺ donors were pretreated with AZT, exposed to the indicated viruses, and an IFNγ Elispot assay was performed using anti-Gag EM71-1 (white symbols) or anti-Pol EM23 (filled symbols) as effectors. Anti–DC-SIGN (8A5 + 1B10), anti-CD4 (Q4120), and IgG isotype control (CTRL) mAbs (at 20 μg/mL) were added 30 minutes before viral exposure. Each symbol corresponds to an individual donor. The 100% values correspond to IFNγ production by effectors when DCs are treated with isotype control mAbs. Inhibition of HIV exogenous presentation by anti-CD4 (P < .01) and anti–DC-SIGN (P < .05) mAbs was statistically significant (Wilcoxon rank sum test).