Rearrangement of the PH-20 protein on the surface of macaque spermatozoa following exposure to anti-PH-20 antibodies or binding to zona pellucida.
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.
Yudin
A I
AI
Department of Obstetrics and Gynecology, University of California, Davis 95616, USA.
Cherr
G N
GN
Vandevoort
C A
CA
Overstreet
J W
JW
D000818:Animals; D000906:Antibodies; D015815:Cell Adhesion Molecules / Q000276:immunology / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D005260:Female; D006821:Hyaluronoglucosaminidase; D008252:Macaca fascicularis; D008297:Male; D011817:Rabbits; D013084:Sperm-Ovum Interactions / Q000502:physiology; D013094:Spermatozoa / Q000378:metabolism* / Q000502:physiology; D015044:Zona Pellucida / Q000502:physiology
D000906:Antibodies; D015815:Cell Adhesion Molecules; D006821:Hyaluronoglucosaminidase; C066852:hyaluronidase PH-20