Purification and characterization of sperm-coating antigen, identified by a monoclonal antibody.

A procedure was designed for purification of a human seminal plasma-specific antigen (HSP-antigen) identified by a monoclonal antibody produced in this laboratory (mAb 4E6). Pooled human seminal plasma was fractionated by consecutively applied methods: affinity chromatography on Lentil lectin sepharose, gel chromatography on Ultrogel AcA 34 and immunoaffinity on mAb 4E6 coupled CNBr-Sepharose 4B. The antigen-containing fraction obtained after this procedure was proved to be homogeneous when analysed by electrophoresis in polyacrylamide gel. After the consecutive purification procedures the degree of purification was 128 times as compared to the starting material. Electrophoretic analysis of the purified 4E6 antigen under reducing conditions showed that it consisted of 3 polypeptide subunits with molecular weight 70 kDa, 64 kDa and 60 kDa respectively. On the basis of the data obtained from competitive ELISA testing of sera from infertile patients it has been suggested that the identified antigen may be involved in pathogenesis of immunologic infertility.