Auto- and iso-antibodies to antigens of the human reproductive system. I. Results of an international comparative study.

A group of thirty-six sera—mainly from infertile patients in whom sperm antibodies had already been demonstrated—were distributed to thirty-eight laboratories for testing for antibodies to spermatozoal antigens and other potential antigens related to the reproductive system [antigens in zona pellucida, decidual cells, trophoblast and placenta as well as hormones (hCG, FSH and LH)]. Comparison of the results from different laboratories showed that the gelatin agglutination test, the tray agglutination test and the immobilization and cytotoxicity techniques are reliable and reproducible procedures. Sperm agglutinins in sera from women appeared to be nearly exclusively head-to-headagglutinins, whereas sera from men contained predominantly agglutinins reacting with tailantigens. Analysis of results obtained with the above-mentioned techniques indicated that they determine largely the same antibody specificities, though not with the same sensitivity. Thus the tray agglutination test seems to be a sensitive method for the detection of all known specificities of agglutinins, whereas the gelatin agglutination test was relatively insensitive for detection of head-to-head agglutinins. In contrast, the tube-slide agglutination technique was the most sensitive for head-to-head agglutinins but did not disclose tail-to-tail agglutinins. Both sera with head-to-head and tail-to-tail agglutinins were able to induce immobilization and cytotoxicity in the presence of complement (if being of a complement-fixing immunoglobulin class), but at a lower sensitivity. The various newer approaches cannot yet be finally evaluated, but positive findings wereobtained in most of the test systems, for example in testing for anti-LDH-X activity and forantibodies to zona pellucida.