Immunohistochemistry

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Antibody staining on an embryo of Drosophila melanogaster (black-bellied fruit fly). The antibody recognizes an unknown antigen in the lumen of the tracheal system .

Immunohistochemistry ( IHC , also known as immunohistology ) is a method used in biology and medicine to make proteins or other structures visible with the help of labeled antibodies . If the antibodies are marked with fluorescent dyes , one speaks of immunofluorescence .

The method can be used, for example, to determine in which tissue the protein is present and also in which compartment of the cell it is located. For example, transcription factors that are localized in the cell nucleus can only be stained in the cell nucleus, membrane proteins only in parts of the cell membrane , etc. Fixed tissue is used for antibody staining , which is either from whole animals (embryos of zebrafish , Drosophila melanogaster etc.) or from tissue sections may exist (for example microtome sections of organs of the mouse or humans). Cells from body fluids or punctures u. The like that have been applied to a slide by means of centrifugation or grown on a slide ( cell culture technique) can also be examined immunohistochemically.

In medical histology, IHC is usually used to identify and classify tumor cells that express certain antigens . Tumors that appear morphologically the same but differ in their growth or settlement behavior (aggressiveness, metastases) or in their response to therapy can be assigned. Recent research has shown that certain cell properties can be directly related to the effectiveness of therapeutic molecules (targeted therapy, e.g. Herceptin for certain breast cancer ). Research is working intensively on such "tumor antibodies" that are directed directly against cancer cells.

Principle of immunohistochemical staining

The detection is based on the affinity of antibodies for a certain tissue property ( epitope ) as an antigen-antibody reaction . Ideally, there is a specific and strong bond between the antibody and the epitope. The antibody is coupled to a detection system that makes its presence in the preparation visible. By means of various detection systems, even small amounts of epitopes can be amplified. The goal is to detect a signal at the location of the epitope (and only there) with sufficient strength.

See also

Commons : Immunohistochemistry  - Album with pictures, videos and audio files

Individual evidence

  1. ^ Gudrun Lang: Histotechnology . Springer-Verlag, 2013. ISBN 9783709111901 . P. 271