Inhibition of bovine fertilization in vitro by antibodies to SP-10

J Reprod Fertil. 1996 Jul;107(2):287-97. doi: 10.1530/jrf.0.1070287.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acrosome / immunology*
  • Animals
  • Antibodies, Monoclonal / pharmacology*
  • Antigens*
  • Antigens, Surface / immunology*
  • Cattle
  • Fertilization in Vitro*
  • Gonadal Steroid Hormones*
  • Humans
  • Male
  • Membrane Proteins
  • Proteins / immunology*
  • Sperm Capacitation
  • Sperm Motility


  • ACRV1 protein, human
  • Antibodies, Monoclonal
  • Antigens
  • Antigens, Surface
  • Gonadal Steroid Hormones
  • Membrane Proteins
  • Proteins