A new murine model of autoimmune orchitis induced by immunization with viable syngeneic testicular germ cells alone. I. Immunological and histological studies.

Experimental autoimmune orchitis (EAO) was produced in C3H/He mice with as high as 100% incidence by two or three s.c. injections of 1 x 10(7) viable syngeneic testicular germ cells (TC) without resorting to adjuvants, Bordetella pertussis vaccine, or other immunological manipulations. On day 40 after the first injection of TC, the lesions induced were characterized by interstitial infiltration of inflammatory cells and severe hypospermatogenesis in the testis with resulting whole organ atrophy and, in contrast, by a complete lack of epididymitis. Immunological studies revealed that this form of immunization caused both delayed-type hypersensitivity and humoral antibody responses to syngeneic TC. We compared the susceptibilities to the induction of this type of EAO among six different strains of inbred mice comprising A/J, AKR, BALB/c, C3H/He, C57BL/6 and DBA/2 mice. All strains except for DBA/2 mice developed lesions of EAO to a greater or lesser extent, and severe disease was induced with high frequency in two strains, C3H/He and A/J. As this murine model of EAO can be induced without the use of Freund's complete adjuvant and B. pertussis vaccine, it is simply 'autoimmune' in nature and may provide new ways for further investigation into the immunological mechanisms which regulate deleterious autoimmune reactions to germ cell antigens leading to the male infertility.