Ouchterlony assay

Ouchterlony Assay

The Ouchterlony assay, also known as the Ouchterlony double diffusion test, is a widely used immunological method for the detection and quantification of antibodies and antigens. It was first developed by the Swedish scientist Örjan Ouchterlony in 1948.

Principle

The Ouchterlony assay is based on the principle of double diffusion in agar or agarose gel. In this method, both the antigen and the antibody are allowed to diffuse freely in the gel medium. When they meet, they form a visible precipitation line, also known as a precipitin line, which indicates the presence of an antigen-antibody complex.

Procedure

The procedure of the Ouchterlony assay involves several steps. First, wells are cut into the agar or agarose gel. The antigen is then placed in the central well, while the antibodies are placed in the surrounding wells. The gel is then incubated at room temperature to allow diffusion. After a certain period of time, the formation of precipitin lines can be observed.

Applications

The Ouchterlony assay has a wide range of applications in various fields of biology and medicine. It is commonly used in diagnostic immunology for the detection of specific antibodies in patient serum, in vaccine development for the quantification of antigens, and in research for the study of antigen-antibody interactions.

Limitations

Despite its usefulness, the Ouchterlony assay has several limitations. It is not suitable for the detection of small amounts of antigens or antibodies, and it cannot provide quantitative results. Moreover, it requires a relatively large amount of sample and is time-consuming compared to other methods.

See also

• Immunodiffusion
• Radial immunodiffusion
• Immunoprecipitation