Effects of antibodies to sperm surface fertilization antigen-1 on human sperm-zona pellucida interaction.

OBJECTIVE

To investigate the effects of antibodies to well-defined sperm surface antigens (the fertilization antigen [FA-1] and germ-cell antigen [GA-1]) and nuclear antigen (protamine) on human sperm-zona interaction.

DESIGN

Number of total and acrosome-reacted human sperm bound to the human zona pellucida and the sperm movement characteristics assessed by computer-aided sperm analysis were evaluated after incubation of sperm with the antibodies.

SETTING

Academic research environment approved by the Institute Review Board.

PATIENTS

Human oocytes were obtained from ovaries removed at surgery. Semen from fertile donors was used in all assays.

INTERVENTIONS

Human oocytes were stored in salt solution at -80 degrees C until used. Spermatozoa were treated with the antibodies to various sperm antigens.

MAIN OUTCOME MEASURES

Total and acrosome-reacted sperm bound to zona pellucida and sperm movement characteristics were evaluated after 3 to 5 hours of incubation of the antibodies with human sperm.

RESULTS

Anti-FA-1 antibodies significantly reduced human sperm fusion with zona-free hamster oocytes and sperm binding to the human zona pellucida but did not affect binding of acrosome-reacted sperm and sperm movement characteristics. Anti-GA-1 and antiprotamine antibodies did not affect sperm-oocyte interaction, acrosomal reaction, or sperm motility.

CONCLUSIONS

Antibodies to FA-1 but not to GA-1 and protamine inhibit human sperm-zona interaction.