Inhibition of mouse in vitro fertilization by an antibody against a unique 18-amino acid domain in the polysulfate-binding domain of proacrosin/acrosin

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Date
2002
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Abstract
Objective: To determine the contribution of the polysulfate-binding domain (PSBD) of acrosin during sperm penetration.
Design: To inhibit the in vitro fertilization of mouse zona-intact oocytes by using a polyclonal antibody raised against an 18-amino acid peptide of proacrosin (anti-PSBD).
Setting: Unit of Reproduction and Development, Faculty of Biological Sciences, Pontifical Catholic University of Chile.
Patient(s): None.
Intervention(s): A polyclonal antibody against the (43)IFMYHNNRRYHTCGGILL(60) peptide was raised in New Zealand female rabbits. The specificity of the antibody was evaluated by an ELISA. Zona-intact mouse oocytes were coincubated with capacitated spermatozoa for 3 hours in the presence of 0.63 mg/mL of the antibody or preimmune serum. As a control, we used zona-free mouse oocytes under the same experimental conditions.
Main Outcome Measure(s): We evaluated the fertilization rate of zona-intact and zona-free mouse oocytes by phase-contrast microscopy. An oocyte was considered fertilized when at least one decondensed sperm head was found within the egg cytoplasm. We evaluated 50-60 mouse oocytes in each group in three independent experiments.
Result(s): The anti-PSBD antibody inhibited the fertilization of zona-intact, but not zona-free, mouse oocytes, by capacitated spermatozoa. In addition, the binding of the anti-PSBD to proacrosin/acrosin in a solid-phase assay was inhibited in the presence of polysulfates (fucoidan).
Conclusion(s): The anti-PSBD directed against the PSBD of proacrosin/acrosin inhibited the penetration of capacitated mouse spermatozoa through the zona pellucida. This antibody may be a useful tool to define the roles of the different domains of proacrosin/acrosin during gamete interaction. (C) 2002 by American Society for Reproductive Medicine.
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fertilization, acrosin, acrosome, zona pellucida, sperm
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