Unmasking fluid E, TRIS-buffered EDTA solution, pH 9

Antigen unmasking based on citrate buffer are most frequently used for unmasking hidden epitopes. However for the detection of some antigens or the simultaneous detection of two or more antigens more sophisticated buffers may be required. Unmasking fluid E on Tris/EDTA basis has been used for a number of antigens and is specially useful for the detection of a number of CD markers, P504S, p63 and HMW cytokeratins etc. Aldehyde fixation (Formaldehyde fixation) of tissues generally causes cross-linkage of protein chains and results in masking of antigens present in the treated tissue. This makes the antigen epitopes undetectable for many antibodies applied for immunohistochemistry. Mainly monoclonal antibodies, but also mono-specific polyclonal antibodies will react with reduced binding or no binding at all. Since Formaldehyde fixation is the most important fixation method in routine histology, high temperature unmasking methods for immunohistochemistry, as developed during recent years, are very important tools for cell and tissue research and pathology.