Antigen and antibody purification by immunoadsorption: elimination of non-biospecifically bound proteins

Immunoadsorption is a simple and effective method for purifying antigens and antibodies. The major interfering effect is non-biospecific binding, especially when crude preparations of antibodies or antigens are coupled to the matrix. In this paper various possibilities for eliminating these effects are compared and analysed. It was found that for antigen (AFP) purification pre-elution with a pH 10.0 buffer of high ionic strength (1.0 M) is effective. A major problem in purifying antibodies in the non-biospecific binding of IgG. This can be eliminated by using a non-biospecific immunoadsorbent column, where specific antibodies are not, or only weakly bound and IgG with irrelevant specificity but exhibiting high non-biospecific interaction is retained. This has been applied to preparation of sheep anti-pepsinogen II group protease antibodies.