SPERM IMMOBILIZATION ANTIBODIES IN INFERTILE MALE SERA DECREASE THE ACROSOME REACTION - A POSSIBLE MECHANISM FOR IMMUNOLOGICAL INFERTILITY

Objective: To study the effect of sperm-immobilizing antibodies from m ale sera on spontaneous and A23187-induced acrosome reactions (AR). De sign: Swim-up spermatozoa obtained from three fertile donors were incu bated with 13 sera with sperm-immobilizing antibodies obtained from in fertile men and three control sera obtained from healthy fertile males , Sperm acrosomes were examined by staining with pisum sativum aggluti nin labeled with fluorescein isothiocyanate (30 mu g/ml; Sigma Chemica l Co., St. Louis, MO) as spontaneous and A23187 (used at a final conce ntration of 10 mu M; Sigma Chemical Co.) induced. Results: The inciden ce of spontaneous AR of spermatozoa incubated with antisperm antibody positive male sera (6.2 +/- 0.7) was significantly (P < 0.001) lower t han that of spermatozoa incubated with control sera (10.7 +/- 0.5). An d the incidence of A23187-induced and -inducible (incidence of induced minus spontaneous) ARs of spermatozoa incubated with sperm antibody-p ositive male sera (12.4 +/- 1.9 and 6.2 +/- 1.9) was significantly low er (P < 0.001) than that of spermatozoa incubated with control sera (3 1.0 +/- 0.5 and 20.3 +/- 0.9). Sperm-immobilizing antibody-positive se ra decreased spontaneous, A23187-induced, and inducible ARs. Conclusio ns: Sperm-immobilizing antibodies from male sera interfere with fertil ization by inhibiting the AR.