Immunization of mice with viable syngeneic testicular germ cells (TGC) alone can induce autoimmune responses against
autoantigens of both round and elongating spermatids, resulting in the development of experimental autoimmune
orchitis (EAO). Histological lesions in this EAO model without an adjuvant are characterized by lymphocytic infiltration into the testes, spermatogenic disturbance, and a complete lack of
epididymitis. In this study, we investigated the effects of
vasectomy (
Vx) on TGC-induced EAO expecting that
Vx augments the severity of testicular
inflammation in A/J mice. The results showed that mice receiving
Vx alone exhibited no significant inflammatory cell response in either the testes or epididymides, and mice receiving shamVx+TGC immunization had EAO with no
epididymitis. In sharp contrast, no EAO was found in the testes of any mice receiving Vx+TGC immunization. Instead, caput
epididymitis involving CD4+T cells, CD8+T cells, B cells, and macrophages were induced in them with striking elevation of the tissue levels of both
IL6 and
IL10 mRNA. Furthermore, serum
autoantibodies induced by shamVx+TGC immunization were reactive with both round (immature) and elongating (mature) spermatids; however, those induced by Vx+TGC immunization were specific to acrosomes of mature spermatids and spermatozoa. These unexpected results indicate that
Vx may induce the mode by which autoreactive lymphocytes gain access to TGC
autoantigens in the epididymides, leading to autoimmune responses against the
autoantigens of mature rather than immature spermatids.