Cross-linking of PSGL-1 triggered release of AIF. AIF translocation during activated T-cell death induced by TAB4. Activated T cells were incubated with TAB4 for indicated time, 0 hours (A, untreated cells), 3 hours (B), 4 hours (C), and 6 hours (D). Following fixation, cells were stained with anti-AIF antibody and Hoechst 33342. Subcellular localization of AIF (green) and cell nuclei (blue) were visualized by a Leica SP2 confocal microscope. Arrowhead indicates apoptotic body; arrow, AIF translocation to nucleus; scale bar, 5 μm.