Figure 5

Stimulation of HIV-1 LTR-controlled expression of green fluorescent protein (GFP) by MS-275 and buthionine sulfoximine (BSO), alone or in combination in a Jurkat cell clone (A1). The A1 cell clone, derived from T-lymphoid Jurkat cells, is a model for latent HIV-1 infection. This clone has an integrated GFP/Tat construct under the control of the HIV-1 LTR and displays a basal proportion of cells expressing GFP, which increase following stimuli activating the HIV-1 promoter. A1 cells were incubated for 72 hours with the different treatments, and GFP expression was monitored by standard flow-cytometric techniques and assessed as the percentage of fluorescent cells (indicated for each histogram) beyond the threshold value established using control non-transfected Jurkat cells. One experiment out of three with similar results is shown. The histograms derived from double-drug treatments were found to be significantly different (P < 0.01) from those derived from treatments with a single drug at matched concentrations (Kolmogorov-Smirnoff statistics). Differences between the drug concentrations adopted in this experiment and that in Figure 4A are derived from adjustments due to the different nature of the cell lines adopted.