A one-step purification method for monoclonal antibodies based on salt-promoted adsorption chromatography on a 'thiophilic' adsorbent.

A convenient and fast method for the purification of mouse monoclonal antibodies from the culture media of cloned cells or from ascites fluids by means of salt-promoted chromatography on a 'thiophilic' adsorbent is described. The adsorbent has a capacity to adsorb about 20 mg/ml of immunoglobulins and a broad specificity towards immunoglobulins derived from various animal species irrespective of the type or subclass to which they belong. The recovery of the purified IgG is better than 90% while that for IgM is considerably less, probably due to dissociation occurring during the adsorption-desorption process. This one-step procedure also leads to a considerable concentration of dilute solutions of immunoglobulins. Moreover, the purified Igs are eluted by an essentially salt-free buffer at near neutral pH thus obviating the need for post-treatment of the sample before storage or subsequent conjugation to enzymes for use in immunoassays. This purification method is also well suited for large-scale operations since sample preparation requires only the addition of 0.5 M K2SO4 to the ascited fluid or cell culture medium. The degree of purification obtained is, in certain instances, comparable to that obtained by biospecific affinity chromatography based on antigen-antibody interactions. In contrast to immunosorption and desorption methods, however, there is no risk of contamination of the immunoglobulins purified on the 'thiophilic' adsorbent by foreign proteins.