Characterization of sperm agglutinating monoclonal antibody and purification of the human sperm antigen

A monoclonal antibody capable of inducing tail-to-tail agglutination of human sperm was purified by ammonium sulfate fractionation and chromatography on DEAE-cellulose. A 75- to 100-fold purification was achieved. The antibody was of the IgG class and composed of gamma 1 heavy chain and lambda light chains. The purified preparation was effective in inducing sperm agglutination at a minimum concentration of 0.55 microgram/mL and was active after storage at 4 degrees C for over 3 months in the presence of sodium azide. The sperm antigen interacting with this YWK-1 antibody was purified by immunoaffinity chromatography on Sepharose 4B conjugated with YWK-1 antibodies. Two interacting proteins were isolated, with estimated Mr of 84 and 20 kD. The 84 kD protein had an isoelectric point in the range of pH 5.7 to 6.1, and probably lacks carbohydrate moieties. The 20 and 84 kD components may share common antigenic determinants.