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Identification and characterization of a sperm peptide antigen recognized by a monoclonal antisperm autoantibody
S Nakamura1, Y Tsuji, Y Nakata
1Department of Obstetrics and Gynecology, Hyogo College of Medicine, Nishinomiya, Japan.
Abstract:
A monoclonal autoantibody (MAb) to mouse sperm was established from a vasectomized mouse. The MAb, termed 4A11, reacted exclusively to mouse and rat live sperm tail, without any cross-reaction with sperm of other mammalian species or any somatic organ tissues in the mouse. MAb 4A11 significantly inhibited in vitro fertilization of mouse ova. Western blotting showed a single band of 67 kDa as the corresponding antigen protein of MAb 4A11. By screening a mouse testis cDNA library with MAb 4A11, one positive clone (964bp) was obtained. DNA sequence of the clone showed no homology with any previously reported mammalian genes, but showed 54% homology with a bacterial gene of sucrose-specific phosphotransferase enzyme II. The rabbit antisera raised to the recombinant protein of the 4A11 cDNA gene showed reaction to mouse, rat, hamster and guinea-pig sperm.
Insights
Researchers developed a novel monoclonal autoantibody (MAb) 4A11 that targets mouse sperm. This antibody inhibits fertilization and identifies a unique sperm tail antigen, offering potential for reproductive research.
Area of Science:
- Immunology
- Reproductive Biology
- Molecular Biology
Background:
- Monoclonal autoantibodies (MAbs) are crucial tools in biological research.
- Identifying specific antigens on sperm is important for understanding fertilization and developing contraceptives.
Purpose of the Study:
- To develop and characterize a novel MAb targeting mouse sperm.
- To investigate the MAb's specificity, effect on fertilization, and identify the target antigen.
Main Methods:
- Generation of a monoclonal autoantibody (MAb) 4A11 from a vasectomized mouse.
- Testing MAb 4A11 specificity against various species' sperm and mouse tissues.
- Assessing MAb 4A11's impact on in vitro fertilization (IVF).
- Western blotting to determine the antigen's molecular weight.
- Screening a mouse testis cDNA library to identify the antigen gene.
Main Results:
- MAb 4A11 specifically binds to mouse and rat sperm tails, with no cross-reactivity.
- MAb 4A11 significantly inhibits mouse in vitro fertilization.
- A 67 kDa protein was identified as the antigen for MAb 4A11.
- A cDNA clone with no homology to known mammalian genes was isolated, showing bacterial gene homology.
- Antisera to the recombinant protein reacted with sperm from multiple species.
Conclusions:
- MAb 4A11 is a specific and potent inhibitor of mouse fertilization.
- The identified antigen is a novel protein with potential roles in sperm function.
- This MAb and antigen represent a valuable tool for reproductive immunology and research.