Confocal analysis of double immunofluorescence assay on EBV-transformed T cells. EBV transformed T cells (NC5) were labeled with the anti-LMP–1 MoAb revealed by a phycoerythrin-ABC complex and by an anti-CD3 MoAb revealed by a fluorescein-goat antimouse immunoglobulin F(ab)′2. Cells labeled with the IgG1 control isotype and the CD3 MoAbs are shown in the bottom left corner as a control. Cells were analyzed with a confocal microscope. The green color represents the fluorescein-labeled CD3 MoAb, the red color represents the phycoerythrin-labeled anti-LMP–1 MoAb, and the yellow color represents the mixture of the two colors as detected by the confocal microscope.