Immunohistochemistry was first described by Coons et al. in the beginning of the 1940s, where the authors used fluorescein-labeled antibodies to visualize bacterial antigens in infected tissues. Today, IHC plays a pivotal role in diagnostics and serves as an essential tool in research.

Immunohistochemistry (IHC) is a powerful microscopy-based technique for visualizing cellular components, for example proteins or other macromolecules in tissue samples. The strength of IHC is the intuitive visual output that reveals the existence and localization of the target-protein in the context of different cell types, biological states, and/or subcellular localization within complex tissues.

The IHC technique was first described by Coons et al. in 1942 where they presented "a method for the detection of antigenic material in tissue cells in which an antibody labelled with fluorescein was employed as a specific histochemical stain". Since then, the IHC method has seen major improvements made in tissue fixation and sectioning methods, antigen retrieval, antibody conjugation and also advancements in microscopy instrumentation. As a result, IHC has become an essential tool in research and is routinely used in healthcare and pathology for e.g. diagnostic purposes and stratification of patients for optimized treatment regimes.

The classical IHC assay involves detection of epitopes expressed by a single protein-target within a tissue sample using a primary antibody capable of binding those epitopes with high specificity. After the epitope-antibody binding event, a secondary antibody high specificity towards the primary antibody is added. The secondary antibody is coupled to a reporter molecule and a chemical substrate is added which reacts with the reporter molecule to produce a colored precipitate at the site of the epitope-antibody complex.

Learn more about the different methods and assays utilized within the Human Protein Atlas here.

References and links

Coons et al (1941). Immunological Properties of an Antibody Containing a Fluorescent Group.
Experimental Biology and Medicine. 47(2), 200-202.
DOI: 10.3181/00379727-47-13084P

Uhlén et al (2005). A human protein atlas for normal and cancer tissues based on antibody proteomics. Mol Cell Proteomics. 4(12):1920-32. PubMed: 16127175 DOI: 10.1074/mcp.M500279-MCP200

Feria Hikmet Noraddin