Comparison of Staining Characteristics of Apoptotic Markers

The tdt-mediated dUTP nick end labeling (TUNEL) assay was used as a standard to compare three antibodies, DNA fragmentation factor, caspase, and Fas, as potential makers in the apoptotic cell pathway. Paraffin sections from normal human, simian, rat and mouse tissues were used consisting of colon, pancreas, and lung for each species. DNA fragmentation factor proved to be a comparable marker to the TUNEL assay but lacked specificity, resulting in the labeling of nonapoptotic cells. Full-length caspase-3 and Fas antibodies did label some apoptotic cells, although neither showed any correlation with TUNEL staining in any tissue types. The ApoTAg TUNEL kit displayed the most consistent and specific apoptotic cell staining with the least amount of background. (The J Histotechnol 28:29, 2005)Submitted: August 12, 2004; Accepted with revisions: December 9, 2004