The presence of intra-tubular lymphocytes in normal testis of the mouse.

Spermatoza contain various autoimmunogenic materials, which are recognized as foreign by the self immune system. Therefore, the blood-tesits-barrier (BTB) formed by Sertoli cells, basal lamina and myoid cells protects autoimmunogeneic spermatozoa from attack by the self immune system. However, the BTB at the tubuli recti (TR) and the rete testis (RT) is known to be incomplete against humoral substances. We investigated here whether the BTB is physiologically penetrated by lymphocytes in mice. We performed light and electron microscopical observation of the seminiferous tubules (ST), the TR and the RT in normal C3H/IHe mice. Although no lymphocytes were observed inside the ST, a very few lymphocytes could be found beyond the basal lamina of the TR and the RT. These lymphocytes were close to testicular spermatozoa in the TR lumen. These findings provide a possibility that lymphocytes may gain access to autoantigens of spermatozoa inside the TR and RT under physiological conditions in mice.