The clinical significance of sperm-zona pellucida binding: 17 years later.

The development of homologous functional bio-assays for sperm quality assessment has been a focal point of reproductive biologists in order to provide a scientifically- based diagnosis in cases of fertilization failure. The availability of viable oocytes still remains an important limiting factor for laboratories to embark on the methodology of assays that examine sperm-oocyte interaction. The use of zonae pellucidae obtained from oocytes derived from post mortem tissue and failed in vitro fertilization cycles, enhanced the availability of zona material. Sperm-zona pellucida binding has been illustrated to be an essential requisite during human fertilization. This fundamental biological step can be measured under hemizona assay as well intact-oocyte test conditions. The sensitivity and specificity of sperm-zona binding results indicated the assay to be positively and significantly correlated with in vitro fertilization outcome. Furthermore, highly significant correlations were demonstrated between normal sperm morphology, hyperactivated motility, sperm creatine kinase activity and the zona binding capacity of a given sperm sample. It was concluded that andrology testing remains an ever-growing component in the work-up of the infertile couple. We enter the next millennium with many questions that remain to be answered by the hand of efficacious screening techniques and a new formidable therapy in intracytoplasmic sperm injection.