| Abstract: | The existence of natural sperm antibodies in fertile subjects requires the application of additional methods in certain cases of significant, but near to the borderline agglutinating titers, in order to distinguish between pathological and natural sperm antibodies. We applied the sperm immobilization test (SIT) of Isojima and an enzyme-linked immunosorbent assay (ELISA) with sera from infertile patients (n = 66) that have been positive in at least one of the agglutination methods of Kibrick and Friberg. The data were compared with the results for a control group of blood donors (n = 50). It was demonstrated that the positive, but low-titer sera in the test of Friberg were often highly positive in ELISA, while the high-titer sera displayed lower OD values. No such correlation was established by SIT. Probably, it would be practical to use ELISA in cases, where no convincing laboratory data exists for immunity against spermatozoa--relevant, but low agglutinating titers, which can be found in fertile subjects. Besides, SIT and ELISA can recognize antigen-antibody systems different from those identified by the agglutinating tests. |
