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Antimicrobial Activity of Human EPPIN, an Androgen-Regulated, Sperm-Bound Protein with a Whey Acidic Protein Motif
The role of epididymal sperm-binding proteins in reproductive tract immunity is now well recognized in addition to their role in sperm maturation. Spermatozoa acquire forward motility and fertilizing ability during their passage through the epididymis, where they acquire a wide variety of proteins b...
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Published in: | Biology of reproduction 2004-11, Vol.71 (5), p.1484-1490 |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | The role of epididymal sperm-binding proteins in reproductive tract immunity is now well recognized in addition to their role
in sperm maturation. Spermatozoa acquire forward motility and fertilizing ability during their passage through the epididymis,
where they acquire a wide variety of proteins belonging to different classes. Previously, we demonstrated that EPPIN ( ep ididymal p rotease in hibitor), an androgen-regulated, sperm-binding protein containing protease-inhibitory motifs, is expressed specifically in
the testis and epididymis. In the present study, we investigated the antibacterial activity of EPPIN against Escherichia coli and the mechanism of antimicrobial action. EPPIN exhibited dose- and time-dependent antibacterial activity that was relatively
insensitive to salt. However, EPPIN lost its antibacterial activity completely on reduction and alkylation of its cysteines,
indicating the importance of disulfide bonds for its activity. EPPIN permeabilized the outer and inner membranes of E. coli , which is consistent with its ability to induce striking morphological alterations of E. coli membranes as shown by scanning electron microscopy. EPPIN did not cause disruption of eukaryotic membranes in the rat erythrocyte
hemolytic assay. The present results indicate that EPPIN has a role in the innate immune system of human epididymis. |
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ISSN: | 0006-3363 1529-7268 |
DOI: | 10.1095/biolreprod.104.031567 |