Figure 5.

C7a induces nuclear alterations characteristic of apoptosis. (A) Nuclear condensation. Uninfected HL-60 cells were untreated (1) or treated with 5 μM C7a (2) for 6 h. Alternatively, HL-60 cells were untreated (3) or treated with 2.5 μM C7a (4) for 24 h. After incubation with C7a, cell nuclei were stained with Hoechst 33342. Inserts: Single cell indicated by the arrow, ×25 magnification. The assay was repeated three times, and representative images are shown; (B) DNA fragmentation. HL-60 cells (3 × 10⁶) were treated (lane 3) with 5 μM of C7a or not (lane 2) for 18 h. Lane 1: MW standard. The assay was repeated three times, and a representative gel is shown; (C) Cell cycle analysis. HTLV-1 infected C81 cells were cultured with 1.25 μM C7a (bottom panel) or not (top panel) for 48 h. Cells were stained with propidium iodide (50 μg/mL) and cell cycle analysis was performed by flow cytometry. Percentage of cells in each phase of the cycle is shown.