TTI-621 (arrow) can be observed at the interface between the Sézary cell and macrophage. Gold-labeled TTI-621 was incubated with Sézary cells and macrophages for 5 minutes before scanning electron microscopy. (A) Sézary cell (SzC) attached to Mϕ (original magnification ×15 000). (B) Gold-labeled TTI-621 at the interface between the Sézary cell and the Mϕ (original magnification ×50 000).