Defects in the regulatory clearance mechanisms favor the breakdown of self-tolerance during spontaneous autoimmune orchitis.
We identified aberrations leading to spontaneous autoimmune orchitis (AIO) in mink, a seasonal breeder and natural model for autoimmunity. This study provides evidence favoring the view that a malfunction of the clearance mechanisms for apoptotic cell debris arising from imbalances in phagocyte receptors or cytokines acting on Sertoli cells constitutes a major factor leading to breakdown of self-tolerance during spontaneous AIO. Serum anti-sperm antibody titers measured by ELISA reflected spermatogenic activity without causing immune inflammatory responses. Orchitic mink showed excess antibody production accompanied by spermatogenic arrest, testicular leukocyte infiltration, and infertility. AIO serum labeled the postacrosomal region, the mid and end piece of mink sperm, whereas normal mink serum did not. Normal serum labeled plasma membranes, whereas AIO serum reacted with germ cell nuclei. Western blot analyses revealed that AIO serum reacted specifically to a 23- and 50-kDa protein. The number of apostain-labeled apoptotic cells was significantly higher in orchitic compared with normal tubules. However, apoptosis levels measured by ELISA in seminiferous tubular fractions (STf) were not significantly different in normal and orchitic tubules. The levels of CD36, TNF-alpha, TNF-alpha RI, IL-6, and Fas but not Fas-ligand (L), and ATP-binding cassette transporter ABCA1 were changed in AIO STf. TNF-alpha and IL-6 serum levels were increased during AIO. Fas localized to germ cells, Sertoli cells, and the lamina propria of the tubules and Fas-L, to germ cells. Fas colocalized with Fas-L in residual bodies in normal testis and in giant cells and infiltrating leukocytes in orchitic tubules.
Pelletier
R-Marc
RM
Département de pathologie et biologie cellulaire, Université de Montréal, QC,Canada. marc.pelletier@umontreal.ca
Yoon
Suk Ran
SR
Akpovi
Casimir D
CD
Silvas
Emil
E
Vitale
María Leiza
ML
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001323:Autoantibodies / Q000096:biosynthesis / Q000276:immunology; D001327:Autoimmune Diseases / Q000378:metabolism* / Q000662:veterinary*; D001814:Blood-Testis Barrier / Q000502:physiology; D018955:CD36 Antigens / Q000096:biosynthesis; D007124:Immunoenzyme Techniques; D007202:Indicators and Reagents; D015850:Interleukin-6 / Q000096:biosynthesis; D007962:Leukocytes / Q000276:immunology; D008297:Male; D008854:Microscopy, Electron; D008907:Mink / Q000502:physiology*; D009707:Nucleosomes / Q000276:immunology / Q000648:ultrastructure; D009920:Orchitis / Q000378:metabolism* / Q000473:pathology / Q000662:veterinary*; D017634:Self Tolerance / Q000276:immunology*; D012671:Seminiferous Tubules / Q000502:physiology; D012708:Sertoli Cells / Q000276:immunology / Q000502:physiology; D013094:Spermatozoa / Q000276:immunology; D013739:Testosterone / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D019014:fas Receptor / Q000276:immunology
D001323:Autoantibodies; D018955:CD36 Antigens; D007202:Indicators and Reagents; D015850:Interleukin-6; D009707:Nucleosomes; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D013739:Testosterone