Visualization of Tag7 and Fas at the cell contact region by confocal microscopy. The larger oval cell in the center is the K562 target, and the smaller cell at the top right is the CD4⁺CD25⁺ lymphocyte (10.0×/1.40 NA oil objective). (A) Decoration with anti-Tag7 antibodies and FITC-labeled anti-IgG. (B) Decoration with phycoerythrin-labeled anti-Fas antibodies. (C) Image superposition.