As₂O₃or IFN-α + As₂O₃ induced apoptosis in HTLV-1 infected cell lines.

(A) FACS, (B) DAPI staining, or (C) ΔΨm collapse analyses of HTLV-1–infected cells after various treatments. (A) MT-2 cells were treated with buffer control, IFN-α, As₂O₃, or IFN-α + As₂O₃ for 60 hours. Cells were then harvested and washed in PBS without Ca^++/Mg²⁺. They were stained using the Vybrant Apoptosis kit. Annexin V conjugated to fluorescein allowed the identification of apoptotic cells, whereas PI allowed the identification of dead cells. Apoptotic cells were annexin V⁺ and PI⁻. (B) DAPI staining of MT-2 cells after the same treatments. Magnification × 40. (C) ΔΨm Collapse was measured with the Apoalert Mitochondrial Membrane Sensor kit. Results are representative of at least 2 experiments performed with different HTLV-1–transformed cells.