Methods for measurement of antibody/antigen affinity based on ELISA and RIA

Various enzyme-linked immunosorbent assay or radioimmunoassay methods are currently used to quantify the antibody-antigen interaction. Only those based on indirect competition--enzyme-linked immunosorbent assay or radioimmunoassay--can provide the real thermodynamic affinity of the antibody for its antigen. They can be applied to a variety of experimental situations, some of which are reviewed here.