TYRAMINE AMPLIFICATION TECHNIQUE IN ROUTINE IMMUNOHISTOCHEMISTRY

Signal amplification in immunohistochemistry via binding of biotinylat ed tyramine to proteins near the site of peroxidase-labeled antibodies is a promising new technique, but studies investigating a wide range of markers are lacking, The tyramine amplification technique (TAT) was investigated on 85 antibodies using a simple and fast protocol, and T AT results were compared to those obtained with conventional immunohis tochemistry. Using TAT, most of the markers could be 5- to 50-fold fur ther diluted and still showed identical staining results compared with standard stainings (maximal 500-fold). However, the variable reactivi ty of the different markers with TAT underlines the need for individua l testing of every antibody to determine the optimal dilution. Some an tibodies against cell adhesion molecules could be demonstrated for the first time in archival, formalin-fixed tissue sections. TAT, if caref ully evaluated, offers a revolutionary improvement for modern immunost aining, either to increase sensitivity or primary antibody dilutions ( cost reduction). From a methodological point of view, immunohistochemi stry has not reached its limits by far and TAT is an important progres sive step in this developmental process.