PURIFICATION OF HUMAN SEMINAL PLASMA NO-7-ANTIGEN BY IMMUNOAFFINITY CHROMATOGRAPHY ON BOUND MONOCLONAL-ANTIBODY

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  • 1 January 1982
    • journal article
    • research article
    • Vol. 49  (2) , 449-456
Abstract
Human seminal plasma (HSP) No. 7 antigen was purified by immunoaffinity of chromatography on bound 1C4 monoclonal antibody (Moab). The pooled HSP protein was applied to a CNBr-activated Sepharose 4B column of bound 1C4 Moab .gamma.-globulin and the antibody bound fraction (fr) eluted was further purified by rechromatography in the same way. The purified antigen in the antibody bound fr obtained by rechromatography gave a single band on SDS-PAGE [sodium dodecylsulfate-polyacrylamide gel electrophoresis] in a position corresponding to a MW of 15,000 daltons. This preparation was 196.2 times more effective than the original HSP protein in neutralizing the sperm immobilizing activity of 1C4 Moab. The purified HSP No. 7 antigen contained Fe, but was different from lactoferrin and transferrin. It did not show any enzymatic activities, such as those of acid phosphatase, LDH [lactic dehydrogenase] or trypsin inhibitor, and shared antigenicity with human milk protein. It was present in seminal plasma as a molecule with a higher MW, but seemed to be cleaved to a monomer of 15,000 daltons during purification procedures. This antigen is present on spermatozoa as sperm-coating antigen and the corresponding antibody can immobilize spermatozoa with complement.