In this example, the T-cell shown is a cytotoxic T cell. A cytotoxic T cell has CD8 antigen, but no CD4 antigen. Consider the possibility that there were three MoAbs used in this tube. The orange labeled MoAbs are specific for the CD3 antigen on T cells, the green labeled MoAbs are specific for the CD4 antigen on T cells and the blue labeled MoAbs are specific for the CD8 antigen on T cells.
A true cytotoxic T cell would emit both orange and blue colors after it passes through the laser as shown in the image to the right. The T-helper cells, as shown on the previous page, would fluoresce orange and green.
MoAbs in any combination can be used in the same staining tube, as long as the fluorochromes can be separated into their respective fluorescent channels for appropriate analyzing.