Solubilized human zona pellucida competes with a fucosylated neoglycoprotein for binding sites on the human sperm surface.

OBJECTIVE

To evaluate the implication of fucose binding sites on the sperm surface in the sperm-zona pellucida (ZP) binding by examining the ability of a fucosylated neoglycoprotein to compete with solubilized zona proteins for sperm binding.

DESIGN

The binding of a fucosylated neoglycoprotein to spermatozoa was analyzed in relation to sperm capacitation and the actual acrosomal status. The effect of solubilized ZP material on the binding was examined.

SETTING

Private hospital, public research center, and university department.

PATIENTS, PARTICIPANTS: Healthy volunteers with normal sperm parameters.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Fluorescence signal detected by fluorescence-activated cell sorting or fluorescence microscopy on spermatozoa incubated with fluorescein isothiocyanate-labeled fucosylated neoglycoprotein.

RESULTS

There was a small subpopulation of spermatozoa that showed a strong binding activity for the fucosylated neoglycoprotein, and the size of this subpopulation increased with the time of exposure to capacitating conditions. The binding sites were located on the head (mainly on the acrosomal region) of acrosome-intact spermatozoa. The neoglycoprotein binding was competitively inhibited by solubilized ZP.

CONCLUSIONS

The data show that a commercially available fucosylated neoglycoprotein competes with solubilized ZP proteins for binding sites on the sperm surface. Further research into the relationship between the neoglycoprotein binding and zona binding is warranted to evaluate the potential diagnostic usefulness of this neoglycoprotein.