Binding of human spermatozoa to lectin-coated agarose microbeads

An inability or decreased ability of spermatozoa to bind to the zona pellucida (ZP) may be at the origin of many cases of poorly explained or idiopathic infertility. It would be clinically useful to be able to distinguish this condition from other causes of infertility. A major problem in testing the sperm-ZP binding ability is the paucity of biological ZP. Examination of whether sperm binding to PNA-, UEA-1-, WGA-, Con A-, or PSA-coated agarose microbeads reflected sperm binding to biological ZP and correlated with in vitro fertilization rates showed that only binding to WGA-coated microbeads showed significant positive and negative predictive values when compared to IVF rates in 2 x 2 contingency. Sperm binding to PNA, Con A, and PSA was indiscriminately high, irrespective of IVF rate. Human spermatozoa did not bind to UEA-1-coated agarose microbeads. Furthermore, sperm binding to WGA-coated microbeads correlated with sperm morphology ratings. These results implicate terminal N-acetyl-D-glucosamine and/or sialic acid (specific saccharides for WGA) in sperm-ZP interaction and also suggest that the use of lectin-coated microbeads may represent an initial step in the development of a synthetic sperm binding assay.