SUPPRESSIVE EFFECT OF CYCLOSPORINE-A ON DELAYED-TYPE HYPERSENSITIVITYTO SYNGENEIC TESTICULAR CELLS

We have investigated the immunosuppressive effect of cyclosporin A (Cs A) on delayed-type hypersensitivity (DTH) to syngeneic testicular cell s (TC). DTH to syngeneic TC was induced by subcutaneous (sc) immunizat ion with viable syngeneic TC and was augmented by a high dose of cyclo phosphamide (CY)-pretreatment. DTH was suppressed by administration of CsA in a dose-dependent manner. When the mice were immunized alone or with 100 mg/kg of CY-pretreatment, 30 mg/kg or more of CsA suppressed DTH to TC. In mice immunized with 200 mg/kg of CY-pretreatment, 50 mg /kg of CsA was needed to suppress DTH. DTH is thought to play a key ro le in the induction and/or maintenance of experimental autoimmune orch itis (EAO). Our data show that DTH to syngeneic TC induced by immuniza tion is suppressed by administration of CsA. Pretreatment of mice with immunization and administration of CsA suppressed DTH significantly w hen the mice were challenged with immunization with CY-pretreatment. H owever, DTH was rather enhanced significantly in mice pretreated with administration of CsA alone without preimmunization. Therefore, even t hough administration of CsA with immunization suppresses DTH, administ ration of CsA alone might rather eliminate suppressive mechanism resul ting in augmentation of DTH.