Partial inhibition of cell-mediated immunity (CMI) by niridazole: effect upon development of autoimmune aspermatogenic orchitis (AIAO) in guinea pigs.

The effects of Niridazole upon the development of autoimmune aspermatogenic orchitis (AIAO) was studied in guinea pigs. Niridazole administration before, during, or three days after alloimmunization with sperm cells emulsified in Freund's complete adjuvant (FCA) produced slight changes in some correlates of cell-mediated immunity. No significant changes in humoral immunity or testicular histopathology can be observed at these periods. When Niridazole was administered ten days after alloimmunization, a significant inhibition of all manifestations of cell-mediated immunity against spermatozoa was observed. Thirty days after alloimmunization, half of the animals studied failed to develop significant histopathological changes in testis or epididymis. However, the titer of cytotoxic antibodies to testicular cells increased from threefold to fourfold, when compared to those of alloimmunized animals not receiving Niridazole. The critical period for cell interactions concerned with the full expression of AIAO was found to be between ten and fifteen days after alloimmunization.