CREATINE-KINASE IMMUNOCYTOCHEMISTRY OF HUMAN SPERM-HEMIZONA COMPLEXES- SELECTIVE BINDING OF SPERM WITH MATURE CREATINE KINASE-STAINING PATTERN

Objective: To examine the clinical significance of the increased sperm cytoplasmic content that is due to a fault of spermatogenesis, we hav e further studied the relationship between increased sperm creatine ki nase (CK) concentrations and diminished fertilizing potential in men. In the present work, we used CK immunocytochemistry of human sperm-hem izona (HZ) complexes to examine whether the distribution of mature (cl ear heads), intermediate (sperm heads with light stippling), and immat ure (heads with heavy stippling or with solid CK staining) spermatozoa bound to the HZ would follow the incidence of these sperm in the samp les tested, or if there is a preferential binding by the mature sperm. Design: Two pairs of HZ were exposed to washed semen and to their swi m-up sperm fractions. The sperm and sperm-HZ complexes were treated wi th a CK antibody followed by horseradish peroxidase immunostaining, an d the sperm were evaluated for maturity. Setting: Men presenting for f ertility evaluation were studied in two university-based andrology lab oratories. Results: The binding of the HZ was selective for mature spe rm as indicated by the incidence of intermediate and immature sperm in washed semen versus bound to the HZ (intermediate: 20.0% versus 1.4%; immature: 7.6% versus 0.5% [mean +/- SEM]) or in swim-up sperm fracti ons versus the HZ (intermediate: 18.7% versus 3.4%; immature: 2.5% ver sus 0.2%). The binding was almost exclusive to normal sperm (96.4% to 98.1%) whether the HZ were exposed to washed semen or swim-up fraction s in spite of the five to ten times higher incidence of intermediate a nd immature sperm. Conclusions: Mature sperm selectively bind to the z ona. We suggest that spermatozoa with immature CK-staining patterns ar e deficient in the site(s) of oocyte recognition and binding.