Page "Cell biology" Paragraph 37

* Immunostaining, also known as immunohistochemistry, is a specialized histological method used to localize proteins in cells or tissue slices.

Unlike regular histology, which uses stains to identify cells, cellular components or protein classes, immunostaining requires the reaction of an antibody directed against the protein of interest within the tissue or cell.

Through the use of proper controls and published protocols ( need to add reference links here ), specificity of the antibody-antigen reaction can be achieved.

Once this complex is formed, it is identified via either a " tag " attached directly to the antibody, or added in an additional technical step.

Commonly used " tags " include fluorophores or enzymes.

In the case of the former, detection of the location of the " immuno-stained " protein occurs via fluorescence microscopy.

With an enzymatic tag, such as horse radish peroxidase, a chemical reaction is carried out that results in a dark color in the location of the protein of interest.

This darkened pattern is then detected using light microscopy.