Exogenous IL-8 stimulates HIV-1 replication in PBL. (A) CD8-depleted PBL were treated with the indicated concentrations of IL-8 and infected with HIV-1_BaL (A), HIV-1_BRU (B), or HIV-2_CBL23 (C). Supernatants were collected twice weekly and replenished with fresh medium.

IL-8-expressing cells in lymphoid tissue from HIV-1-infected individuals. IL-8-expressing cells found by intracellular immunohistochemical staining of a lymph node section from an AIDS patient are shown at a magnification of ×200. In the high-power magnification (×630; inset), the intracellular localization of IL-8 protein to the Golgi-endoplasmic reticulum complex can be seen.

Depletion of endogenous IL-8 inhibits HIV-1 replication in MDM and PBL. (A) MDM were treated with either mouse IgG1 or an antibody that neutralizes IL-8 activity (each at 20 μg/ml) and infected with HIV-1_BaL. Medium was collected for the RT assay and replenished twice weekly. (B) Immunodepletion of IL-8 or blocking the IL-8 receptors CXCR1 and CXCR2 suppresses HIV-1 replication in CD8-depleted PBL. CD8-depleted PBL were treated with the indicated antibodies (20 μg/ml) and infected with HIV-1_BRU. Medium was collected and replenished twice weekly. Supernatants were analyzed for RT activity on the indicated number of days after infection. Data shown are representative of four experiments.

Exogenous IL-8 stimulates HIV-1 replication in AM and MDM. (A) AM were cultured for 5 days before infection with HIV-1_BaL and then treated with IL-8 at either 0.5, 5, or 50 ng/ml. Supernatants (25%) were collected twice weekly and replaced with fresh medium. Viral replication was assessed by quantifying the RT activity present in the supernatants at several time points after infection. (B) MDM were treated with IL-8 at the indicated concentrations every 3 days beginning 1 day before infection with HIV-1_BaL. Supernatants were analyzed for RT activity 8 days after infection. The increase observed with IL-8 treatment in the range from 5 to 100 ng/ml was determined to be statistically significant relative to no treatment (P < 0.05, Student's t test). (C) Antibodies to CXCR1 and CXCR2 block the ability of IL-8 and GRO-α (each at 25 ng/ml) to stimulate HIV-1_BaL replication in MDM. Supernatants were analyzed for RT activity 19 days after infection. Data shown are representative of five experiments.

The small-molecule inhibitor SB225002 inhibits HIV-1 replication in macrophages and T lymphocytes. (A) MDM were treated with 0.01% DMSO (the carrier control) or SB225002 at the doses indicated every 3 days beginning 1 day before infection with HIV-1_BaL. The data shown are the mean of the RT activity present in triplicate wells measured on the days indicated. Cellular viability, proliferation, and activation were measured on day 13 by an MTT-based assay and determined to be 0.353 ± 0.036, 0.382 ± 0.040, 0.293 ± 0.022, and 0.276 ± 0.040 for treatment with 0, 25, 100, and 300 nM SB225002, respectively. (B) PHA-activated PBL were treated with DMSO (0.01%) or the indicated doses of SB225002 every 3 days beginning 1 day before infection with HIV-1_BRU. HIV-1 replication was assayed by measuring the amount of RT activity in the supernatants on days 3, 6, and 9 after infection. Cellular viability, proliferation, and activation were measured on day 9 by an MTT-based assay and determined to be 0.052 ± 0.017, 0.031 ± 0.020, 0.023 ± 0.017, and 0.046 ± 0.018 for treatment with 0, 100, 300, and 1,000 nM SB225002, respectively. These experiments are representative of six (A) and three (B) independent experiments performed with cells from different donors.