Confocal analysis of GzmB binding to HL-60 cells and human leukocytes. (A) Comparison of TF-Bio (left column) and GzmB-Bio (right column) binding to HL-60 cells. Binding at 4°C occurred exclusively on the cell surface, as demonstrated by the 3-dimensional reconstruction (top row) or the section view (bottom row). (B) Costaining of lymphocytes with anti-CD8 FITC (left; section view) or granulocytes with anti-CD16 FITC (right; 3-dimensional reconstruction) and GzmB-Bio/SA-Cy3. (C) Double staining of monocytes with anti-CD14 FITC and GzmB-Bio/SA-Cy3. Shown is the section view of GzmB-Bio binding (top left) or CD14-FITC (top right) and the overlay of both (bottom). Neutro indicates neutrophil granulocytes. White scale bar = 50 μm.