Extraction of circulating gastrointestinal cancer antigen using solid-phase immunoadsorption system of monoclonal antibody-coupled membrane.

An immunoadsorption system of monoclonal antibody immobilized on a polyolefin alloy fiber is described for extraction of serum gastrointestinal cancer antigen (GICA). Continuous circulation or single passage of plasma from gastrointestinal cancer patients through this antibody-fiber matrix resulted in 90% depletion of circulating GICA in 2 h using 0.6 mg immobilized antibody, and 90% depletion in 5 min using 8 mg antibody. Continual circulation resulted in total GICA removal in both cases. Desorption of antibody or of antibody-containing complexes was minimal. This methodology provides a selective and convenient means of removing any targeted substance by monoclonal antibody from the serum, and thus overcomes many of the shortcomings associated with conventional plasmapheresis.