Two-step IHC Polymer-based detection kits
Detection kits for immunohistochemistry (IHC) based on the polymers method are more recent than traditional kits using avidin and biotin conjugates such as ABC kits. Polymer-based kits offer several advantages over ABC kits, especially for multi-staining (multiplex) applications on the same tissue section or where high levels of endogenous biotin may be a problem.
The IHC detection systems based on the polymers method consist of a polymer of an active enzyme linked to a secondary antibody specific for a target primary antibody. This format makes it possible to significantly increase the amount of enzyme present at the site of localization and therefore a greater signal by converting a greater quantity of substrate into precipitate. Moreover, this system allows a one-step protocol instead of two with the ABC system (biotinylated antibody + avidin-enzyme complex).
There are now IHC polymer detection kits of a new generation which allow to amplify the signal with a protocol in 2 steps. The added step may involve an intermediate antibody, a polymer helper or an antibody enhancer. Regardless of the method used, the purpose of this additional step is to increase the amount of polymer at the site of the antigen in order to increase the signal.