Testicular origin of immunobead-reacting antigens in human sperm

Objective: To investigate, by means of immunobinding technique, the antigenic surface expression of human vasa efferentia sperm as compared with that of ejaculated sperm. Design: Briefly, vasa efferentia sperm, retrieved microsurgically, and donors' ejaculated sperm controls) were used. Patients, Participants: Men with congenital absence of the vas deferens, undergoing sperm aspiration as part of their infertility treatment, and controls who were donors of our sperm bank were first assayed by direct immunobead test and, if found negative, were exposed to sera containing known high titers of antisperm antibodies and then retested by indirect immunobead test. Results: The data showed no difference in binding titers and class of immunoglobulins between vasa efferentia and ejaculated sperm. Conclusions: These findings suggest that, in humans, sperm acquire those surface antigens commonly detected by immunobinding test within the testes before their transit through the epididymis.