Digoxin inhibits HIV-1 replication in PBMCs.

<p>(A–B) PHA/IL-2-activated human PBMCs were infected with R5 BaL strain of HIV-1 at a MOI of 10⁻². Following infection, cells were incubated in the presence of indicated doses of digoxin or DMSO (control). Equal concentrations of DMSO were present in each treatment. (A) After 8–10 days, media was harvested for analysis of HIV-1 Gag protein expression by p24^CA ELISA. Peak levels of Gag expression averaged ∼800 pg/ml at ∼8 days post-infection. ELISA results were averaged from ≥4 experiments and displayed as a fraction relative to DMSO (+) control, error bars are SEM, and statistical significant changes of treatments from DMSO control are indicated by asterisks as detailed in “<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003241#s4" target="_blank">Materials & Methods</a>”. (B) Cells were assessed following digoxin treatment for cell viability by Trypan blue exclusion (TB, black diamonds) or XTT assay (grey circles) as indicated. Shown is data averaged from ≥5 and ≥3 experiments, respectively, and displayed as a fraction relative to DMSO (+) control, error bars are SEM, and statistical significance indicated by asterisks as mentioned above. (C–F) CD8⁺-depleted PBMCs from chronically HIV-1-infected patients were activated by treatment with anti-CD3 and anti-CD28 antibodies to induce virus growth in cell culture. Cells were treated with either (C, D) digoxin or (E, F) the NRTI, 3TC. Media was harvested at multiple times points to assess virus replication by p24^CA ELISA of Gag. Shown (C, E) are the viral growth curves from 20 days of cell culture and (D, F) the dose response effects of the indicated drugs after only 14 days of culture. Effect of drugs on cell viability (Cell Viab., grey circles) was also tested in parallel by XTT assay. Note: cell viability data for (C, E) are shown on the y-axis adjacent to Gag levels while (D, F) is displayed in a similar manner but on the same y-axis as Gag expression. Inhibition and viability results shown (C–F) are derived from assays performed on three different patients, expressed relative to DMSO-treated cells, error bars are SEM, and statistical significance indicated by asterisks as described above.