Affinity chromatography: a tool for enzyme immunoassay.

Affinity chromatography has been widely used for enzyme purification and for the preparation of antigen-enzyme conjugates. Most enzyme immunoassay use immunoadsorbent (specific or double insolubilized antibodies) which makes automation difficult as centrifugation and washing steps are necessary. We propose affinity chromatography for rapid separation of antigen-enzyme bound to antibodies from free conjugate and its application in enzyme immunoassay. We describe enzyme immunoassays for human placental lactogen and progesterone which use delta 5,3-ketosteroid isomerase as marker and depend upon retention by specific absorbent of enzyme conjugate not bound to antibodies.