Crossed immunoelectrophoresis.

Ressler first described in 1960 (1) a form of immunoelectrophoresis now called crossed immunoelectrophoresis (CIE) or two-dimensional immunoelectrophoresis, which was later improved by Laurell (2), Clarke and Freeman (3), and Weeke (4), among others. CIE is superior to the classical immunoelectrophoresis, according to Grabar and Williams (5), particularly in providing better resolution and quantitative capabilities. It combines the electrophoretic separation of the sample proteins in agarose gel with electrophoresis at right angles to the initial separation in an antibody-containing agarose. Each protein separated during the first dimension forms a separate precipitation peak during the second dimension. Moreover, the area under any protein peak is directly proportional to the concentration of that protein in the analyzed sample and inversely proportional to the concentration of antibody to that protein in the antiserum used.