Chronological changes of delayed-type hypersensitivity in mice immunised with testicular germ cells alone.

Experimental autoimmune orchitis (EAO), comprising a breakdown of the testicular immune privilege, is one of the models of immunological male infertility. EAO is characterised by CD4 + T-cell-dependent lymphocytic inflammation and augmented delayed-type hypersensitivity (DTH) against testicular antigens. We previously established an EAO model in mice by immunisation with viable syngeneic testicular germ cells (TGC) alone. However, the sequential change of DTH during development of this EAO has not been analysed yet. In this study, the DTH response during TGC-induced EAO was investigated by the injection of syngeneic TGC protein into the ears of mice. The results showed that a significant DTH response was observed on injection of 20 μg TGC protein, but not on that of 0.2 or 2 μg TGC protein. Also, the level of the DTH response to 20 μg TGC protein was highly relevant to the pathology of EAO development. These results indicate that the DTH response on injection of 20 μg TGC protein into the ears of mice is effective for predicting the pathology of EAO development.