Immunocytochemistry

Immunocytochemistry relates to chemicals interacting with immune responses of cells within the host. Immunocytochemistry is a fundamental lab practice which uses antibodies that target antigenic receptors on the cell membranes to determine the presence of certain diseases (e.g., cancers). It differs from immunohistochemistry in that immunocytochemistry uses cells grown within a culture. There are many methods to perform immunological stains on tissues, including the direct method of staining. One method involves the use of an antibody that is bonded directly to the antigen (marker) on a cell with a fluorescent or colored dye bonded directly to the antibody. Another method includes the indirect method where the antigen is stained with a primary antibody which bonds directly to the antigen, followed by a secondary antibody which bounds to the primary antibody. Next, a tertiary reagent is applied, which bounds to the secondary antibody, with an enzymatic end. When the quarternary reagent, or substrate, is applied, the enzymatic end of the tertiary reagent converts the substrate into a pigment and another product, which stains the cell, usually a reddish brown color. Some examples of substrates used , (also known as chromogens) are AEC (3-Amino, 9-Ethyl Carbazole), or DAB (Diaminobenzidine). Presence of one of these reagents after application of chromogen represents a positive stain. Immunocytochemical stains are used mainly when an H&E (Hematoxylin and Eosin)diagnosis cannot be made.

External links

• Immunocytochemistry Staining Protocol