Immunoaffinity purification of protein antigens

The unique high specificity of antibodies, both polyclonal and monoclonal, makes them extremely valuable tools for rapid, selective purification of antigens. In principle, the antibody immobilized on a column support is used to selectively adsorb antigen from a mixture containing many other proteins (1,2). The other proteins, for which the antibody has no affinity, may be washed away, and the purified antigen then eluted from the immunoadsorbent. In order to dissociate the antigen from its high affinity antibody, the conditions for elution are necessarily extreme (1-3) and thus must be carefully chosen to permit isolation of active protein.