Mapping of Epitopes Relevant for Induction of Acrosome Reaction on Human Zona Pellucida Glycoprotein-4 Using Monoclonal Antibodies

Authors


  • Satish K. Gupta and Jian Wang are joint corresponding authors.

Correspondence

Jian Wang, Department of Reproductive Biology, Shanghai Institute of Planned Parenthood Research, Shanghai-200032, China.

E-mail: wangjiansippr@126.com

Satish K. Gupta, Reproductive Cell Biology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India.

E-mail: skgupta@nii.ac.in

Abstract

Problem

To decipher structural and functional aspects of human zona pellucida glycoprotein-4 (ZP4), the epitopes recognized by monoclonal antibodies (MAbs) have been mapped.

Method of study

Recombinant human ZP4-mediated induction of acrosome reaction in human sperm was studied in the absence and presence of ZP4-specific MAbs. The epitopes of MAbs were mapped using recombinant peptides expressed in Escherichia coli.

Results

Monoclonal antibodies (MA-1662, MA-1671) against human ZP4 showed specific binding to ZP matrix of human eggs in an indirect immunofluorescence assay. Both the antibodies showed significant (P < 0.05) inhibition in the baculovirus-expressed recombinant ZP4-mediated acrosome reaction. MA-1671 recognized N-terminal fragment of ZP4 and minimal epitope mapped to amino acid residues 126–130 (PARDR), whereas MA-1662 reacted to C-terminal fragment and minimal epitope mapped to amino acid residues 256–260 (ENELV).

Conclusions

The epitopes corresponding to both N- and C-terminal parts of human ZP4 may be relevant for its biological activity.

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