Recent studies have demonstrated that testicular inflammatory disorders leading to impairment of spermatogenesis are an important cause for male infertility, and autoimmune orchitis is noticed as one of main reasons161718. Experimental autoimmune orchitis (EAO) is a model of chronic testicular inflammation resulting in male infertility3419202122. The pathological condition is characterized by T-cell-dependent lymphocytic inflammation and damage to the seminiferous tubules involving the shedding and apoptosis of germ cells3419202122232425262728. In rats and mice, EAO is classically induced by immunization with testicular homogenate (TH) plus complete Freund’s adjuvant (CFA) and Bordetella pertussis (BP); it is thought that treatment with the two adjuvants is required to enhance immune responses, resulting in the breakdown of testicular immune privilege272930. We have recently reported that CFA and BP treatment alone augments autoimmune reactions against some testicular autoantigens31. These results indicate that the treatment with adjuvants alone can evoke autoimmune reactions against some AIs irrespectively with exposure to TH31. We have previously established another EAO model induced in both A/J and C3H/He mice with a very high incidence by two subcutaneous injections of viable syngeneic TGC without using any adjuvant21. Our EAO model is unique because serum autoantibodies are only against acrosomal regions of sperm and spermatids, but not Sertoli cells, Leydig cells and seminiferous tubular basement membrane3252632. This model showed that the immunologically privileged state of the testis is easily overcome using only two TGC injections.