ANALYSIS OF ACTIVE ANTIBODY CONCENTRATION - SEPARATION OF AFFINITY AND CONCENTRATION PARAMETERS

Antibody binding to surfaces with differing amounts of immobilised ant igen was measured in a biosensor system using surface plasmon resonanc e detection. Binding rates obtained during the initial binding phase o n high density antigen surfaces were proportional to antibody concentr ation and independent of antigen-antibody affinity. One antibody calib ration curve covering the range from 0.5 to 160 nM (0.08-25 mu g/ml) a ntibody was valid for IgG antibodies with different antigen specificit ies. To illustrate the use of this methodology active antibody concent rations were analysed in culture media and in rabbit serum.