THE USE OF ANTICLUSTERIN MONOCLONAL-ANTIBODIES FOR THE COMBINED ASSESSMENT OF HUMAN SPERM MORPHOLOGY AND ACROSOME INTEGRITY

Clusterin is an abundant protein in the human male reproductive tract which appears to be produced by the testis, epididymis and the seminal vesicles. Using monoclonal antibodies and an amplified immunoperoxida se technique, we have identified two apparently biochemically distinct forms of clusterin on human spermatozoa. Morphologically abnormal spe rmatozoa have an extensive surface coating of conventional 80 kDa nati ve clusterin, but this form of clusterin is not detectable on normal s permatozoa. Normal spermatozoa, however, contain within the acrosomal cap a different form of clusterin, reactive with an anticlusterin alph a-chain antibody. Agglutinated spermatozoa, most of which are grossly abnormal, were intensely labelled with the antibody against convention al 80 kDa clusterin, suggesting that the 'clustering' properties of th is protein may play a role in the aggregation of abnormal spermatozoa. Anticlusterin monoclonal antibodies may be useful for semen analysis. Staining spermatozoa with anticlusterin monoclonal antibodies is a te chnically simple method which provides a visually obvious means of ass essing spermatozoa morphology and acrosome status simultaneously. The current data also suggest that different functions of clusterin in the reproductive tract may be attributed to different molecular forms of the protein.