Immunohistochemical Localization of Antigens in Human Spermatozoa

A high sensitivity indirect immunohistochemical technique was employ ed to study the development and localization of antigenic sites in human sperm during transport through the male genital tract. The technique involved horseradish peroxidase as label and rabbit antibodies against a human testicular protein preparation and against washed testicular and seminal sperm seminal plasma and serum protein fractions. Through complement fixation antibodies crossreacted with the highest titer occurring with antiseminal plasma and the lowest with antitesticular protein fraction. Antiseminal plasma reacted with the acrosome posterior head cap neck and the intermediate segment of seminal sperm. Only acrosome and on occasion the neck of testicular or epididymal sperm showed reactivity. Sperm antiwashed with saline or water reacted only with the acrosome and the neck of seminal sperm though there was slight staining of the acrosome of testicular and epididymal cells. Antitesticular protein fraction reacted with the acrossome and neck of testicular and epididymal sperm though the reaction was less evident with seminal sperm cells. Antiserum proteins especially albumin and gamma globulin selectively stained the acrosome of seminal sperm though testicular and epididymal sperm cells did not show as definite a reaction. The results tend to support the existence of progressive layers of antigenic proteins covering the head neck and intermediate segment of sperm though the presence of intrinsic antigens cannot be discounted until more sophisticated experimental techniques are available.