Purification of the antigen specific for amoebiasis.

Two methods used for the purification of specific antigen for amoebiasis were affinity chromatography and agarose gel electrophoresis. The IgG fraction of the serum from a patient with amoebic liver abscess showing a specific band in the IEP test was coupled to CNBr-activated Sepharose 4B. After passage through the immunoadsorbent column of the crude or partially purified extract of Entamoeba histolytica, followed by acid dissociation, specific antigen was obtained. This antigen gave only one band in the IEP test against the serum which gave multiple bands upon testing with the crude antigen. With the agarose gel electrophoresis, fraction 2 from the slit was found to contain specific antigen. Rabbits immunized with the excised agarose strip of this fraction produced antibodies giving 2 precipitating bands in the IEP test, one of which was specific for amoebiasis.