Figure 5.

The CCR5–02 mAb interferes with R5 HIV-1 replication. (A) CCR5–02 (10 μg/ml) or an isotype-matched control mAb were tested for HIV-1 suppressive activity by using the X4 NL4–3 or the R5 BaL viral strains and activated PBMC target cells. Untreated culture supernatants were used as control (medium). As a control for suppressive activity, 10 nM of SDF-1α for NL4–3, and 10 nM RANTES or MIP-1α for BaL were used. Viral replication was monitored by quantitating gag p24 antigen levels (ng/ml) at day 7 postinfection. Data represent the mean ± SD of triplicate analyses; one representative experiment is shown of three performed (100% control for NL4–3-infected PBMCs = 13 ng/ml p24; for BaL-infected PBMCs = 9.25 ng/ml p24). (B) A dose-response curve of HIV-1 suppressive activity for RANTES and CCR5–02 mAb is shown by using the R5 BaL viral strain and activated PBMC target cells. Viral replication was monitored as in A. Data represent the mean ± SD of triplicate analyses; one representative experiment is shown of three performed. (C) A dose-response curve of HIV-1 suppressive activity for CCR5–02 mAb, using a primary R5 viral strain and activated PBMCs, and the dual-tropic SF2 viral strain and MT2-B7 cells. Viral replication was monitored as in A. (100% control for SF2-infected CCR5-transfected MT2 cells = 0.65 ng/ml p24, 4 days postinfection; for R5 primary isolate-infected PBMCs = 3.15 ng/ml p24, 7 days postinfection.) Data represent the mean ± SD of triplicate analyses; one representative experiment is shown of three performed. (D) SCID mice were reconstituted with 20 × 10⁶ PBMCs and injected with 200 μg mAb before and after HIV-1 infection. Two weeks after infection, plasma concentrations of HIV-1 RNA were determined. Values represent RNA copies/ml of individual animals. Only mice with values above detection level (>300 copies/ml) are shown. Viral infection in mice with undetectable viral plasma levels was assessed by coculture of peritoneal cells with activated PBMCs.