Immunohistochemistry
Immunohistochemistry or IHC refers to the process of detecting antigens (e.g., proteins) in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues.[1] IHC takes its name from the roots "immuno," in reference to antibodies used in the procedure, and "histo," meaning tissue (compare to immunocytochemistry).
Immunohistochemical staining is widely used in the diagnosis of abnormal cells such as those found in cancerous tumors. A video showing preparation for immunohistochemistry (8 minutes) and then 20 minutes scanning through immunohistochemically stained tissues near colon cancers, shows different degrees of deficiency in three DNA repair proteins (ERCC1, PMS2 and KU86) and one mitochondrial protein (CCOI).[2] Specific molecular markers are characteristic of particular cellular events such as proliferation or cell death (apoptosis). IHC is also widely used in basic research to understand the distribution and localization of biomarkers and differentially expressed proteins in different parts of a biological tissue.
Visualising an antibody-antigen interaction can be accomplished in a number of ways. In the most common instance, an antibody is conjugated to an enzyme, such as peroxidase, that can catalyse a colour-producing reaction(see immunoperoxidase staining). Alternatively, the antibody can also be tagged to a fluorophore, such as fluorescein or rhodamine (see immunofluorescence).
Sample preparation
Preparation of the sample is critical to maintain cell morphology, tissue architecture and the antigenicity of target epitopes. This requires proper tissue collection, fixation and sectioning. A solution of paraformaldehyde is often used to fixate tissue, but other methods may be used. The tissue may then be sliced or used whole, dependant upon the purpose of the experiment or the tissue itself. Sections can be sliced on a variety of instruments, most commonly a microtome or cryostat and are
Immunohistochemical staining is widely used in the diagnosis of abnormal cells such as those found in cancerous tumors. A video showing preparation for immunohistochemistry (8 minutes) and then 20 minutes scanning through immunohistochemically stained tissues near colon cancers, shows different degrees of deficiency in three DNA repair proteins (ERCC1, PMS2 and KU86) and one mitochondrial protein (CCOI).[2] Specific molecular markers are characteristic of particular cellular events such as proliferation or cell death (apoptosis). IHC is also widely used in basic research to understand the distribution and localization of biomarkers and differentially expressed proteins in different parts of a biological tissue.
Visualising an antibody-antigen interaction can be accomplished in a number of ways. In the most common instance, an antibody is conjugated to an enzyme, such as peroxidase, that can catalyse a colour-producing reaction(see immunoperoxidase staining). Alternatively, the antibody can also be tagged to a fluorophore, such as fluorescein or rhodamine (see immunofluorescence).
Sample preparation
Preparation of the sample is critical to maintain cell morphology, tissue architecture and the antigenicity of target epitopes. This requires proper tissue collection, fixation and sectioning. A solution of paraformaldehyde is often used to fixate tissue, but other methods may be used. The tissue may then be sliced or used whole, dependant upon the purpose of the experiment or the tissue itself. Sections can be sliced on a variety of instruments, most commonly a microtome or cryostat and are