A Brief Introduction of Immunoprecipitation

A Brief Introduction of Immunoprecipitation

What is Immunoprecipitation?

Protein is always the focus of research for global scientists for it is the most important molecule in living forms. Immunoprecipitation is a classical method to researching interaction different proteins on the basis of specificity between antibody and antigen and it is also regarded as an effective way to recognize the mutual physiological action between two kinds of proteins in cells. It presents that the immune complexes produce protein precipitation in some certain condition after the specific binding between soluble antigen and antibody in liquid or gel. Immunoprecipitation, agglutination, neutralization reaction and the reaction between antigen and antibody are called classical immunological techniques. With the deepening of the protein research, more complicated methods are produced on the basis of combination of immunoprecipitation and other methods. Thus methods of protein analysis become more various and its application area become wider. This technology has a wide application in gene, protein, and their reaction.


Basic strategy of Immunoprecipitation is that utilizing the high affinity in antibody and antigen to test and bind the target molecule of liquids. Immunoprecipitation is advancing with the development of science and technology. In early stage, researchers use gel electrophoresis to test immunoprecipitation protein. They add antigen solution into holes of permeable matrix and add antisera into nearby holes. With the spreading of antigens and antibodies, macromolecular protein complexes separate out as the precipitation line which can be recognized by naked eyes in the solution. The early improvement of immunoprecipitation is to promote polymer reaction to make immune complexes separate out from the solution. Later, researchers found that using secondary antibody and immune complexes’ antibody to build a net can save the step of titration experiments of primary antibody of every antigens. This methods is still in use. In 70s in 20th century, people start use solid phase reaction. They protein A fixed in staphylococcus aureus to adsorbent antibody and bind with certain antigen. With the development of science and technology, it evolves. The microspheres of protein A or G are used to separate antibody complex from antigen complex to test antigen or target protein.