Inhibition of bovine fertilization in vitro by antibodies to SP-10.
The inhibiting effect on fertilization of antibodies to the intra-acrosomal protein SP-10 was studied in a bovine in vitro fertilization model. Indirect immunofluorescence showed that antibodies to human SP-10 localized to the acrosomal region of methanol-fixed, but not live, bovine spermatozoa, confirming the intra-acrosomal localization of bovine SP-10. The presence of the SP-10 protein in bovine spermatozoa was further established by immunoblotting of extracts of bovine spermatozoa with monoclonal antibodies and polyclonal antibodies to human SP-10. The antibodies identified a pattern of immunoreactive peptides similar to human, baboon, monkey and pig SP-10. Fertilization experiments in vitro demonstrated that monoclonal antibodies, as well as polyclonal antibodies, to human SP-10 significantly reduced fertilization rates of bovine oocytes by bovine spermatozoa. SP-10 antibodies exerted their anti-fertilization effect by reducing sperm-zona secondary binding. Consistent with the accessibility of the SP-10 antigen following capacitation, SP-10 antibodies also reduced the ability of capacitated spermatozoa to complete the acrosome reaction. Furthermore, SP-10 antibodies affected the motility of capacitated spermatozoa, while not affecting the motility of noncapacitated spermatozoa.
Coonrod
S A
SA
Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station 77843, USA.
Herr
J C
JC
Westhusin
M E
ME
D000177:Acrosome / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D000941:Antigens; D000954:Antigens, Surface / Q000276:immunology*; D002417:Cattle; D005307:Fertilization in Vitro; D012739:Gonadal Steroid Hormones; D006801:Humans; D008297:Male; D008565:Membrane Proteins; D011506:Proteins / Q000276:immunology*; D013075:Sperm Capacitation; D013081:Sperm Motility
C512729:ACRV1 protein, human; D000911:Antibodies, Monoclonal; D000941:Antigens; D000954:Antigens, Surface; D012739:Gonadal Steroid Hormones; D008565:Membrane Proteins; D011506:Proteins