Effects of the fusion peptides on monocyte viability. (A) Selective killing of monocytes. Peripheral blood mononuclear cells were incubated with the indicated peptides as described in the text, and then they were analyzed by flow cytometry. Cells were also incubated with propidium iodide (PI) to check for membrane integrity. Data are representative of at least three independent experiments. (B) Cytotoxic effects of the fusion peptides. Purified monocytes were cultured in complete medium and then treated for 60 min with various peptide concentrations, incubated with PI and then analyzed by flow cytometry. Data are from three independent experiments. (C) Killing kinetics. Purified CD14+ monocytes or CD4+ T cells were incubated with the tested peptides (10 μM each) and then analyzed by flow cytometry at various time points after PI incubation. Data are from three independent experiments. (D) Induction of apoptosis. After incubation with the peptides for 60 min at 37 °C, monocytes were analyzed by dual-color flow cytometry for annexin V and PI staining. Quantitative data from three independent experiments are shown in (E). * p < 0.05, ** p < 0.01, *** p < 0.001.