Rearrangement of the PH-20 protein on the surface of macaque spermatozoa following exposure to anti-PH-20 antibodies or binding to zona pellucida

• Published in: Molecular reproduction and development 1998-06, Vol.50 (2), p.207-220
• Main Authors: Yudin, Ashley I., Cherr, Gary N., VandeVoort, Catherine A., Overstreet, James W.
• Format: Article
• Language: English
• Subjects: acrosome reaction; Animals; Antibodies; Biological and medical sciences; Cell Adhesion Molecules - immunology; Cell Adhesion Molecules - metabolism; Cell Membrane - metabolism; Female; Fundamental and applied biological sciences. Psychology; Hyaluronoglucosaminidase; Macaca fascicularis; macaque sperm; Male; Mammalian male genital system; Morphology. Physiology; PH-20; Rabbits; Sperm-Ovum Interactions - physiology; Spermatozoa - metabolism; Spermatozoa - physiology; Vertebrates: reproduction; zona pellucida; Zona Pellucida - physiology
• ISSN: 1040-452X; 1098-2795
• DOI: 10.1002/(SICI)1098-2795(199806)50:2<207::AID-MRD12>3.0.CO;2-3

Capacitated cynomolgus macaque sperm have a surface hyaluronidase (PH‐20) that is evenly distributed over the entire head and can be visualized at the ultrastructural level using a secondary antibody labeled with colloidal gold . Exposure of sperm to mono‐specific, bivalent polyclonal antibodies to PH‐20 causes a rapid clustering of PH‐20 . The predominant morphological consequence of PH‐20 redistribution is its aggregation along the lateral edge of the sperm head. Monovalent Fab fragments of the anti‐PH‐20 antibody bound to the sperm head but did not induce a change in PH‐20 distribution. PH‐20 aggregation was observed in almost all sperm following treatment with the polyclonal antibody, but only about 20% of the sperm had morphological acrosome reactions, regardless of the time of exposure or the concentration of antibody. There was morphological evidence of swelling of the acrosomal matrix in over 50% of the sperm following exposure to anti‐PH‐20 antibodies. Anti‐PH‐20 Fab fragments did not induce the acrosome reaction or acrosomal matrix swelling. Sperm bound to macaque zona pellucida also showed aggregation of the PH‐20 protein as soon as 30 sec after sperm‐zona interaction. This aggregation was not observed when macaque sperm were bound to hamster zona pellucida. When macaque sperm were surface‐labeled with biotin and then incubated with anti‐PH‐20 antibodies or macaque zona pellucida, there was no evidence of a global surface protein rearrangement, although PH‐20 protein was aggregated on the surface of the same sperm cells. An increase in levels of internal sperm Ca++ was measured in association with the antibody‐induced PH‐20 aggregation. Fab fragments did not increase Ca++ levels, but when they were crosslinked with anti‐Fab antibody there was a significant Ca++ increase and induction of acrosome reactions. Anti‐PH‐20 Fab fragments did not block macaque sperm binding to macaque zona pellucida or the zona‐induced acrosome reaction. We conclude that PH‐20 on the sperm surface is involved in sperm‐zona pellucida interaction and the zona‐induced acrosome reaction. Mol. Reprod. Dev. 50:207–220, 1998. © 1998 Wiley‐Liss, Inc.