Human peripheral blood cells (PBMCs) were either left unstimulated (left image) or stimulated with 10 ng/mL PMA and 1 ug/mL Ionomycin for four hours. Cells were then stained with CD355 (CRTAM) antibodies, as well as with CD8 antibodies. Flow cytometry was performed with the MACSQuant^® Analyzer. The Tandem Signal Enhancer has been used to increase binding specificity of tandem-dye–conjugated antibodies. Cell debris and dead cells were excluded from the analysis based on scatter signals and propidium iodide fluorescence or 4',6-diamidino-2-phenylindole (DAPI) fluorescence, as in the case of tandem conjugates.