Mode of inflammatory cell infiltration in testes of mice injected with syngeneic testicular germ cells without adjuvant.

We previously established an experimental model for autoimmune inflammation of the testis in mice by active immunisation with viable syngeneic testicular germ cells without the use of adjuvants. In the present study, the mode of spread of the inflammation was investigated histologically to determine vulnerable sites for the inflammatory cell infiltration. The results showed that lymphocytic infiltration first appeared in the tunica albuginea adjacent to the tubuli recti and the rete testis. In the next stage, infiltration with lymphocytes, macrophages, polymorphonuclear leucocytes and plasma cells occurred around the tubuli recti and subsequently a mixture of these cells spread centrifugally to the peripheral interstitium of the testis with persistent involvement of the region of the tubuli recti and the tunica albuginea. In the final stage, the inflammatory cells invaded the tubules. However, even in cases with the most severe testicular inflammation, the interstitium in the rete testis region showed only slight inflammatory changes, and no inflammation was seen in the ductuli efferentes, the epididymis or the vas deferens.