Visualization

Detection systems

In order to amplify the signal, indirect labelling techniques are almost always used, with peroxidase as the most common enzyme. Optimized avidin-biotin systems and the polymer conjugate system EnVision are equally sensitive. The major differences between the two are 1) the former are three step methods, while the latter is a two-step method, and 2) in avidin-biotin based systems false positive staining due to endogenous biotin may be a problem which is avoided with polymer conjugate systems. Changing from an older labelled streptavidin-biotin method to the most sensitive avidin-biotin based systems or EnVision in our laboratory gave a three fold enhancement on the average.

References

Vyberg M, Nielsen S. Dextran polymer conjugate two-step visualization system for immunohistochemistry. Appl Immunohistochem 1998; 6:3-10.