title: Fas ligand in bull ejaculated spermatozoa:A quantitative immunocytochemical study.
abstract: Apoptosis, or programmed cell death, provides a way to remove redundant cells at the end of their lifespan and thus acts as a homeostatic mechanism, maintaining the correct number of cells in the body by balancing their production and death. In the testis, this process seemed to play a pivotal role in spermatogenesis. It is generally accepted that Sertoli cells control the germ cell population through one of the best-known apoptotic pathways, the Fas/Fas L paracrine signal transduction system, in which a Fas ligand (Fas L) expressed by Sertoli cells induces apoptosis when it binds with its receptor, Fas, expressed by the germ cells. Recently, we demonstrated the presence of Fas antigen in normal ejaculated spermatozoa from fertile bulls and suggested that this molecule might have a non-apoptotic, defensive role against injuries, especially oxidative stress. We have now investigated whether bull mature, fertile spermatozoa express not only the Fas receptor but also its natural ligand Fas L. Our results indicate that the whole sperm population expresses Fas L. We suggest that Fas L in bull spermatozoa, like in murine spermatozoa, might be able to kill activated lymphocytes and protect the male gamete from damage by the self-immune system or the cytotoxic activity of leukocytes in the female genital tract.
authors.affiliation: Istituto di Anatomia degli Animali Domestici, Facoltà di Medicina Veterinaria, Università degli Studi di Milano, Milano, Italy. franca.Porcelli@unimi.it
authors.forename: Franca
authors.initials: F
authors.lastname: Porcelli
authors.forename: Daniela
authors.initials: D
authors.lastname: Meggiolaro
authors.forename: Antino
authors.initials: A
authors.lastname: Carnevali
authors.forename: Bruno
authors.initials: B
authors.lastname: Ferrandi
mesh_terms: D000818:Animals; D017209:Apoptosis; D002417:Cattle; D019610:Cytoprotection / Q000276:immunology; D004542:Ejaculation; D053222:Fas Ligand Protein / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D013094:Spermatozoa / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism
chemical_list: D053222:Fas Ligand Protein