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


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


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


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




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.


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).


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