Precipitin

Precipitin is a type of antibody that reacts with a specific antigen to form a visible precipitate. This reaction is known as the precipitin reaction, and it is used in laboratory tests to determine the presence of specific antigens in a sample.

History

The term "precipitin" was first used by Paul Ehrlich in 1891 to describe the reaction that occurs when an antigen is mixed with its corresponding antibody. This reaction was later used as the basis for the development of various laboratory tests, including the Ouchterlony double diffusion test and the immunodiffusion test.

Mechanism

When a precipitin (antibody) encounters its corresponding antigen, it binds to the antigen to form an antigen-antibody complex. This complex then precipitates out of solution, forming a visible precipitate. The amount of precipitate formed is proportional to the amount of antigen present in the sample, allowing for the quantification of the antigen.

Applications

Precipitin reactions are used in a variety of laboratory tests to detect the presence of specific antigens. These tests include the Ouchterlony double diffusion test, the immunodiffusion test, and the immunoelectrophoresis test. In addition to these tests, precipitin reactions are also used in forensic science to determine the species origin of blood and other body fluids.

See also

• Antibody
• Antigen
• Immunology
• Immunodiffusion
• Ouchterlony double diffusion
• Immunoelectrophoresis