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Updated: Aug 21, 2026
Analysis of Epididymal Protein Synthesis and Secretion
Published on: August 25, 2018
Identification and characterization of an antigen recognized by monoclonal antibody TRA 54 in mouse epididymis and
Kélen F Arrotéia1, Paulo P Joazeiro, Aureo T Yamada
1Laboratory of Cytochemistry and Immunocytochemistry, Department of Histology and Embryology, Institute of Biology, State University of Campinas (UNICAMP), PO Box 6109, 13083-970, Campinas, SP, Brazil.
Abstract:
Spermatozoa in testicular fluid are known to have weak forward motility and cannot fertilize eggs. The epididymis is known to participate in sperm maturation leading fertilization, but little is known about the specific epididymal molecules involved in the modification of sperm. In this study, we characterized the new pattern of expression of an antigen previously identified in testicular germ cells by monoclonal antibody (mAb) TRA 54. This antigen is expressed in epididymal and vas deferens epithelial cells in mice older than 24 days but not during younger developmental stages. Evaluation by immunohistochemistry shows that antigen expression is limited to the cytoplasm of a specific cell population of epithelia along the epididymal regions and vas deferens of adult mice. The molecules synthesized and released by epididymal and vas deferens epithelia into their lumen seem to bind on spermatozoa moving down through the ducts. Immunoblot analysis showed that the molecules recognized by mAb TRA 54 in testis and epididymis were similar and share a common epitope involving carbohydrate domains. Interestingly, the antigens identified in epididymal and vas deferens epithelial cells were expressed independently of testicular germ cells and are produced in an androgen-dependent manner. Finally, the molecules recognized by mAb TRA 54 seem to play an important role in spermatogenesis, as well as in epididymal function related to spermatozoa maturation and ability to fertilize.
Insights
A novel antigen identified by monoclonal antibody (mAb) TRA 54 is expressed in mouse epididymal and vas deferens epithelial cells. This molecule plays a crucial role in sperm maturation and fertilization ability.
Area of Science:
- Reproductive Biology
- Developmental Biology
- Molecular Endocrinology
Background:
- Spermatozoa require maturation in the epididymis to achieve fertilizing capacity.
- Specific epididymal molecules mediating sperm modification remain largely uncharacterized.
Purpose of the Study:
- To investigate the expression pattern and function of an antigen recognized by monoclonal antibody (mAb) TRA 54.
- To elucidate the role of this antigen in sperm maturation and male fertility.
Main Methods:
- Immunohistochemistry to evaluate antigen expression in mouse tissues.
- Immunoblot analysis to characterize the antigen's molecular properties.
- Assessment of androgen-dependency of antigen expression.
Main Results:
- The TRA 54 antigen is expressed in epididymal and vas deferens epithelial cells in mice older than 24 days.
- Expression is cytoplasmic, androgen-dependent, and independent of testicular germ cells.
- Antigens in testis and epididymis share a common carbohydrate epitope.
- Epididymal molecules bind to spermatozoa within the ducts.
Conclusions:
- The TRA 54 antigen is a key molecule involved in sperm maturation within the epididymis.
- This antigen contributes to male fertility by enhancing sperm function.
- Androgen regulation of epididymal epithelial cells is critical for sperm development.
