Up to 15% of male infertility has an immunological origin, either due to repetitive infections or to autoimmune responses mainly affecting the epididymis, prostate, and testis. Clinical observations and epidemiological data clearly contradict the idea that the testis confers immune protection to the whole male genital tract. As a consequence, the epididymis, in which posttesticular spermatozoa mature and are stored, has raised some interest in recent years when it comes to its immune mechanisms. Indeed, sperm cells are produced at puberty, long after the establishment of self-tolerance, and they possess unique surface proteins that cannot be recognized as self. These are potential targets of the immune system, with the risk of inducing autoantibodies and consequently male infertility. Epididymal immunity is based on a finely tuned equilibrium between efficient immune responses to pathogens and strong tolerance to sperm cells. These processes rely on incompletely described molecules and cell types. This review compiles recent studies focusing on the immune cell types populating the epididymis, and proposes hypothetical models of the organization of epididymal immunity with a special emphasis on the immune response, while also discussing important aspects of the epididymal immune regulation such as tolerance and tumour control.
Adaptive Immunity ; Animals ; Epididymis/immunology* ; Fertility/immunology* ; Genital Neoplasms, Male/immunology* ; Humans ; Immunity, Innate ; Infertility, Male/immunology* ; Male ; Spermatozoa/immunology*

The epididymal protease inhibitor (Eppin) has recently been cloned in human and mice, which is specifically expressed in the epididymis and testis. Eppin is a cystine-rich secretory protein which contains signal peptide, WAP and BPTI motifs. Eppin is involved in sperm maturation and fertilization, and in the innate immune system of human epididymis. Immunocontraception with Eppin is effective and reliable, but its safety is to be further proved. This paper summarizes the effects of Eppin of fertilization and immunity, as well as its utilization in immunocontraception.
Animals ; Contraception, Immunologic ; Epididymis ; immunology ; Fertility ; physiology ; Haplorhini ; Male ; Mice ; Proteins ; immunology ; physiology ; Spermatozoa ; physiology

Objective: To prepare a polyclonal antibody against human lysozyme-like protein 4 (LYZL4) expressed in the prokaryotic system and identify the distribution of LYZL4 in the testis. METHODS: The full-length cDNA of LYZL4 was cloned into the pET32a plasmid and the expression of the recombinant LYZL4 (rLYZL4) was induced by IPTG. The rLYZL4 was purified by Ni-NTA and chitin affinity chromatography respectively and its bactericidal activity was observed by bilayer agar plate diffusion assay. The purified rLYZL4 was used as an immunogen to generate the polyclonal antibody, followed by examination of the antibody titer by ELISA and its specificity by Western blot. The distribution of LYZL4 in human tissue, sperm and seminal plasma was identified and its subcellular localization in the testis was determined by immunohistochemistry. RESULTS: rLYZL4 was expressed efficiently in the prokaryotic system and exhibited no bacteriolytic activity against M. lysodeikticus and E. coli. The anti-rLYZL4 polyclonal antibody could bind the recombinant protein with a high sensitivity and specificity. LYZL4 was identified in the testis, epididymis and sperm protein extracts and localized in the acrosomal region of round and elongating spermatids. CONCLUSIONS An anti-rLYZL4 polyclonal antibody was successfully prepared using the prokaryotic expression system. LYZL4 was detected in the acrosomal region of round and elongating spermatids, suggesting an association with the structure and function of the acrosome.
Acrosome ; immunology ; Animals ; Antibodies ; analysis ; Blotting, Western ; DNA, Complementary ; Enzyme-Linked Immunosorbent Assay ; Epididymis ; immunology ; Escherichia coli ; Humans ; Immunohistochemistry ; Male ; Muramidase ; genetics ; immunology ; Plasmids ; Recombinant Proteins ; genetics ; Semen ; immunology ; Spermatozoa ; immunology ; Testis ; immunology

OBJECTIVETo provide materials for the study of the function of ESC42 protein specifically expressed in the human epididymis.

METHODSThe ESC42 gene was amplified from the human epididymis cDNA library by PCR and then cloned into prokaryotic expression vector pGEX-4T-1, expressed and purified by recombinant DNA techniques. The specificity of ESC42 protein was identified by Western blot and MALDI-TOF-MS. The database was searched by Ms-Fit.

RESULTSThe recombinant plasmid expressed a Mr 38 x 10(3) fusion protein in E. coli at a level of 30% of the total protein, and the purity was as high as 99%. The ESC42 protein was identified by ESC42 monoclonal antibody and its molecular weight was 11 978.12, tested by MALDI-TOF-MS. The peptide mass fingerprint analysis showed that the coverage rate of the sequence reached 48% with 100% matching. The motif scan in Prosite database reveal that ESC42 belonged to the beta-defensin family and had antibacterial activity.

CONCLUSIONObtaining high purity of rhESC42 protein may lay a foundation for the study of its functions.

Amino Acid Sequence ; Animals ; Antibodies, Monoclonal ; immunology ; Cloning, Molecular ; Defensins ; biosynthesis ; genetics ; immunology ; Epididymis ; metabolism ; Escherichia coli ; genetics ; Gene Library ; Humans ; Male ; Mice ; Mice, Inbred BALB C ; Plasmids ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; immunology