Immunostaining

Immunostaining is a general term in biochemistryin that applies to any use of an antibodyand some colouring agent to detect a specific proteinin a sample. The most common applications are after gel electrophoresisor within tissue slices in immunohistochemical staining.

Antibodiesthat detect the protein of interest are generated by a foreign host species (a polyclonal antibody) or cultured immune cell clones (monoclonal antibodies). After exposure to the foreign protein, the antibodies can be harvested and used as very specific and sensitive detection agents. Antibodies so generated are known as "primary antibodies," as they bind directly to the protein of interest.

Some immunostaining agents can be applied in a single stage, where the primary antibody is directly linked to a colouring agent. Usually this is not the case, and the primary antibody is targeted by a "secondary" antibody, targeting a species-specific part of the structure of the primary antibody.

This alternative is advantageous in many ways. Most importantly, the signal is amplified, as multiple secondary antibodies will bind to a primary antibody. It also allows for a high variety of primary antibodies - researchers can make their own antibodies and not have to conjugate them to a colouring agent themselves. Finally, it means that a variety of colouring agents can be conjugated to any given species of secondary antibody, and are available in ready supply. This has opened the door to "double-labelling" experiments, where several proteins can be co-localised through the use of antibodies for different proteins raised in different species.

See also Western blotand immunohistochemical staining.

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It uses material from the http://en.wikipedia.org/wiki/Immunostaining Wikipedia article Immunostaining.